Re: OT: Digital camera opinions

[Colin Irvine]

On Thu, 6 Jan 2005 22:25:44 +0000,
chateauSPAMKILL.murray@dsl.pipex.com (The Older Gentleman) squeezed
out the following:

>I have to admit that you're absolutely right.
>
>The number of road (ie: not racers) riders I can think of, who can use
>more than, say 80bhp to its absolute full, on public roads, is....
>
><counts fingers>
>
>Zero.

I take it you're excluding overtakes up steep hills two-up with
luggage?

--
Colin Irvine
YZF1000R BOF#33 BONY#34 COFF#06 BHaLC#5
http://www.colin.irvine.dsl.pipex.com/

[Ace]

On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
<Colin.Irvine@spamcop.net> wrote:

>On Thu, 6 Jan 2005 22:25:44 +0000,
>chateauSPAMKILL.murray@dsl.pipex.com (The Older Gentleman) squeezed
>out the following:
>
>>I have to admit that you're absolutely right.
>>
>>The number of road (ie: not racers) riders I can think of, who can use
>>more than, say 80bhp to its absolute full, on public roads, is....
>>
>><counts fingers>
>>
>>Zero.
>
>I take it you're excluding overtakes up steep hills two-up with
>luggage?

But that's about torque, not power.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Champ]

On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:

>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
><Colin.Irvine@spamcop.net> wrote:
>
>>On Thu, 6 Jan 2005 22:25:44 +0000,
>>chateauSPAMKILL.murray@dsl.pipex.com (The Older Gentleman) squeezed
>>out the following:
>>
>>>I have to admit that you're absolutely right.
>>>
>>>The number of road (ie: not racers) riders I can think of, who can use
>>>more than, say 80bhp to its absolute full, on public roads, is....
>>>
>>><counts fingers>
>>>
>>>Zero.
>>
>>I take it you're excluding overtakes up steep hills two-up with
>>luggage?
>
>But that's about torque, not power.

Oh bollox is it. Everyone seems to think torque is about grunt, and
power is about revs, which while having some basis in truth, is far
from the full story.

It should be compulsory for everyone to read this article
http://vettenet.org/torquehp.html before discussing power and torque.
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[Ace]

On Mon, 10 Jan 2005 11:17:55 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>><Colin.Irvine@spamcop.net> wrote:

>>>I take it you're excluding overtakes up steep hills two-up with
>>>luggage?
>>
>>But that's about torque, not power.
>
>Oh bollox is it.

Err, yes, it is. Torque is what you need to accelerate - outright
power with low torque (i.e. only available at high revs) will not
accelrate a vehicle anything like as fast as higher torque but lower
power.

For example, back in t'old days, my XT500 would make mincemeat of a
400/4 in the traffic light grand prix, despite a similar weight (yes,
really - that exhaust weighed a ton) and the Honda making some 25%
more power.

>Everyone seems to think torque is about grunt, and
>power is about revs, which while having some basis in truth, is far
>from the full story.
>
>It should be compulsory for everyone to read this article
>http://vettenet.org/torquehp.html before discussing power and torque.

Indeed you should.

"Torque is the only thing that a driver feels, and horsepower is just
sort of an esoteric measurement in that context. 300 foot pounds of
torque will accelerate you just as hard at 2000 rpm as it would if you
were making that torque at 4000 rpm in the same gear, yet, per the
formula, the horsepower would be *double* at 4000 rpm. Therefore,
horsepower isn't particularly meaningful from a driver's perspective"

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[steve auvache]

Champ wrote
>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>><Colin.Irvine@spamcop.net> wrote:
>>
>>>On Thu, 6 Jan 2005 22:25:44 +0000,
>>>chateauSPAMKILL.murray@dsl.pipex.com (The Older Gentleman) squeezed
>>>out the following:
>>>
>>>>I have to admit that you're absolutely right.
>>>>
>>>>The number of road (ie: not racers) riders I can think of, who can use
>>>>more than, say 80bhp to its absolute full, on public roads, is....
>>>>
>>>><counts fingers>
>>>>
>>>>Zero.
>>>
>>>I take it you're excluding overtakes up steep hills two-up with
>>>luggage?
>>
>>But that's about torque, not power.
>
>Oh bollox is it. Everyone seems to think torque is about grunt, and
>power is about revs, which while having some basis in truth, is far
>from the full story.
>
>It should be compulsory for everyone to read this article
>http://vettenet.org/torquehp.html before discussing power and torque.

Oh please sir I have read it, can I join in now?


--
steve auvache
MZ TS150: for sale still.
Bandit 600

[Champ]

On Mon, 10 Jan 2005 13:01:13 +0100, Ace <b.rogers@virgin.net> wrote:

>On Mon, 10 Jan 2005 11:17:55 +0000, Champ <neal@champ.org.uk> wrote:
>
>>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>>
>>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>>><Colin.Irvine@spamcop.net> wrote:
>
>>>>I take it you're excluding overtakes up steep hills two-up with
>>>>luggage?
>>>
>>>But that's about torque, not power.
>>
>>Oh bollox is it.
>
>Err, yes, it is. Torque is what you need to accelerate - outright
>power with low torque (i.e. only available at high revs) will not
>accelrate a vehicle anything like as fast as higher torque but lower
>power.

Power is the rate at which you can do work (torque). So, there isn't
really such an animal as a high power, low torque engine.

>>It should be compulsory for everyone to read this article
>>http://vettenet.org/torquehp.html before discussing power and torque.
>
>Indeed you should.
>
>"Torque is the only thing that a driver feels, and horsepower is just
>sort of an esoteric measurement in that context. 300 foot pounds of
>torque will accelerate you just as hard at 2000 rpm as it would if you
>were making that torque at 4000 rpm in the same gear, yet, per the
>formula, the horsepower would be *double* at 4000 rpm. Therefore,
>horsepower isn't particularly meaningful from a driver's perspective"

Ok, to go back to the original point - "overtaking up steep hills two
up with luggage". A minimum amount of torque is required to get you
up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
work/time you need power.
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[Champ]

On Mon, 10 Jan 2005 12:07:16 +0000, steve auvache
<dont_spam@thecow.me.uk> wrote:

>Champ wrote

>>It should be compulsory for everyone to read this article
>>http://vettenet.org/torquehp.html before discussing power and torque.
>
>Oh please sir I have read it, can I join in now?

<makes mark on register>

OK, you're cleared.
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[steve auvache]

Champ wrote
>On Mon, 10 Jan 2005 12:07:16 +0000, steve auvache
><dont_spam@thecow.me.uk> wrote:
>
>>Champ wrote
>
>>>It should be compulsory for everyone to read this article
>>>http://vettenet.org/torquehp.html before discussing power and torque.
>>
>>Oh please sir I have read it, can I join in now?
>
><makes mark on register>
>
>OK, you're cleared.

Torque rocks. Horse Power is a meaningless marketing ploy.

In either case there is no substitute for cubes.
--
steve auvache
MZ TS150: for sale still.
Bandit 600

[Champ]

On Mon, 10 Jan 2005 13:08:52 +0000, steve auvache
<dont_spam@thecow.me.uk> wrote:

>Champ wrote
>>On Mon, 10 Jan 2005 12:07:16 +0000, steve auvache
>><dont_spam@thecow.me.uk> wrote:
>>
>>>Champ wrote
>>
>>>>It should be compulsory for everyone to read this article
>>>>http://vettenet.org/torquehp.html before discussing power and torque.
>>>
>>>Oh please sir I have read it, can I join in now?
>>
>><makes mark on register>
>>
>>OK, you're cleared.
>
>Torque rocks. Horse Power is a meaningless marketing ploy.

<looks over spectacles> You sure you read the article?

>In either case there is no substitute for cubes.

As a turbo afficiando, I'm afraid I cannot concur.
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[steve auvache]

Champ wrote
>On Mon, 10 Jan 2005 13:08:52 +0000, steve auvache
><dont_spam@thecow.me.uk> wrote:
>
>>Champ wrote
>>>On Mon, 10 Jan 2005 12:07:16 +0000, steve auvache
>>><dont_spam@thecow.me.uk> wrote:
>>>
>>>>Champ wrote
>>>
>>>>>It should be compulsory for everyone to read this article
>>>>>http://vettenet.org/torquehp.html before discussing power and torque.
>>>>
>>>>Oh please sir I have read it, can I join in now?
>>>
>>><makes mark on register>
>>>
>>>OK, you're cleared.
>>
>>Torque rocks. Horse Power is a meaningless marketing ploy.
>
><looks over spectacles> You sure you read the article?

Fairly. It was a little while ago now, I could easily have forgotten.
Remind me what it was about.



>a turbo

Poor mans substitute.

--
steve auvache
MZ TS150: for sale still.
Bandit 600

[sweller]

Champ wrote:

> > Torque rocks. Horse Power is a meaningless marketing ploy.
>
> <looks over spectacles> You sure you read the article?

I like kittens

--
Simon

http://www.sweller.co.uk/sob/

[Ace]

On Mon, 10 Jan 2005 12:59:30 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 10 Jan 2005 13:01:13 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>On Mon, 10 Jan 2005 11:17:55 +0000, Champ <neal@champ.org.uk> wrote:
>>
>>>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>>>
>>>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>>>><Colin.Irvine@spamcop.net> wrote:
>>
>>>>>I take it you're excluding overtakes up steep hills two-up with
>>>>>luggage?
>>>>
>>>>But that's about torque, not power.
>>>
>>>Oh bollox is it.
>>
>>Err, yes, it is. Torque is what you need to accelerate - outright
>>power with low torque (i.e. only available at high revs) will not
>>accelrate a vehicle anything like as fast as higher torque but lower
>>power.
>
>Power is the rate at which you can do work (torque). So, there isn't
>really such an animal as a high power, low torque engine.

Oh yes there is, and you've ridden them, I'm sure. Any high-revving
bike will by definition make less torque for the same power (the
equations are in your linked page, so I wont repeat them). So if you
compare a thumper making, say, 50bhp at 5000rpm, with a screamer 125
2T making the same power at 20000rpm, you'll find that the latter
makes just a quarter of the torque for the same power.

It's all in the article you posted.

>>>It should be compulsory for everyone to read this article
>>>http://vettenet.org/torquehp.html before discussing power and torque.

>Ok, to go back to the original point - "overtaking up steep hills two
>up with luggage". A minimum amount of torque is required to get you
>up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
>work/time you need power.

No, sorry. Torque is needed to accelerate. The higher torque, the
higher the acceleration. Indeed, a definition of torque is 'rotational
acceleration'.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Mon, 10 Jan 2005 13:44:04 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 10 Jan 2005 13:08:52 +0000, steve auvache
><dont_spam@thecow.me.uk> wrote:
>

>>Torque rocks. Horse Power is a meaningless marketing ploy.
>
><looks over spectacles> You sure you read the article?

No, _you_ didn't. I think what's causing the confusion is that many
people only look at peak torque, or power, without considering where
it's being made and the shape of the curve. But ultimately the
relationship between them at any given engine speed is fixed.

>>In either case there is no substitute for cubes.
>
>As a turbo afficiando, I'm afraid I cannot concur.

Well yes, there is that.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Colin Irvine]

On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> squeezed
out the following:

>On Mon, 10 Jan 2005 12:59:30 +0000, Champ <neal@champ.org.uk> wrote:

>>Ok, to go back to the original point - "overtaking up steep hills two
>>up with luggage". A minimum amount of torque is required to get you
>>up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
>>work/time you need power.
>
>No, sorry. Torque is needed to accelerate. The higher torque, the
>higher the acceleration. Indeed, a definition of torque is 'rotational
>acceleration'.

Actually you're both right. You need power to climb a hill, and the
more power you have the quicker you can climb it. You need torque to
accelerate, and the more torque you have the quicker you can
accelerate.

I stand by my original point - I could not make the overtakes I make
on the Thunderace if it only made 80 bhp, whatever the revs it made it
at.

--
Colin Irvine
YZF1000R BOF#33 BONY#34 COFF#06 BHaLC#5
http://www.colin.irvine.dsl.pipex.com/

[Mick Whittingham]

In article <m4r4u0ttgo9du08d55j36d77ih1nl04m7k@4ax.com>, Ace
<b.rogers@virgin.net> writes
>On Mon, 10 Jan 2005 11:17:55 +0000, Champ <neal@champ.org.uk> wrote:
>
>>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>>
>>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>>><Colin.Irvine@spamcop.net> wrote:
>
>>>>I take it you're excluding overtakes up steep hills two-up with
>>>>luggage?
>>>
>>>But that's about torque, not power.
>>
>>Oh bollox is it.
>
>Err, yes, it is. Torque is what you need to accelerate - outright
>power with low torque (i.e. only available at high revs) will not
>accelrate a vehicle anything like as fast as higher torque but lower
>power.

Correct, the only way this could be incorrect is if you had a variable
drive so you could sit on max BHP all the time while the variable drive
adjusts the torque fed to the driving wheels.
>
>For example, back in t'old days, my XT500 would make mincemeat of a
>400/4 in the traffic light grand prix, despite a similar weight (yes,
>really - that exhaust weighed a ton) and the Honda making some 25%
>more power.
>
>>Everyone seems to think torque is about grunt, and
>>power is about revs, which while having some basis in truth, is far
>>from the full story.
>>
>>It should be compulsory for everyone to read this article
>>http://vettenet.org/torquehp.html before discussing power and torque.
>
>Indeed you should.
>
>"Torque is the only thing that a driver feels, and horsepower is just
>sort of an esoteric measurement in that context. 300 foot pounds of
>torque will accelerate you just as hard at 2000 rpm as it would if you
>were making that torque at 4000 rpm in the same gear, yet, per the
>formula, the horsepower would be *double* at 4000 rpm. Therefore,
>horsepower isn't particularly meaningful from a driver's perspective"
>
Which is 100% correct then he goes and shoots himself in the foot with:
<Repeat after me. "It is better to make torque at high rpm than at low
rpm, because you can take advantage of *gearing*." :-) >

Which is said by a man who has never really designed a gearbox that
works.

Torque at *only high* RPM is a compromise to produce higher BHP while
sacrificing the ability to use it.

If you have torque at *only high* RPM it will be a narrow peak. To be
able to use it you will have to match the gearing to the torque band. If
you drop out of the usable torque band width while going up the box the
motor will not pull in the next gear and you will slow down until you
change down again. To keep in the torque band if it is a high one you
will have to either have a variable speed gear box or go back to the
days of the 50cc bikes with 15 gears (before they were banned in
competitions.)


--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Mick Whittingham]

In article <04k5u0hvhfngrghn3uqusiuduo3o2mt8kq@4ax.com>, Colin Irvine
<Colin.Irvine@spamcop.net> writes
>On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> squeezed
>out the following:
>
>>On Mon, 10 Jan 2005 12:59:30 +0000, Champ <neal@champ.org.uk> wrote:
>
>>>Ok, to go back to the original point - "overtaking up steep hills two
>>>up with luggage". A minimum amount of torque is required to get you
>>>up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
>>>work/time you need power.
>>
>>No, sorry. Torque is needed to accelerate. The higher torque, the
>>higher the acceleration. Indeed, a definition of torque is 'rotational
>>acceleration'.
>
>Actually you're both right. You need power to climb a hill, and the
>more power you have the quicker you can climb it. You need torque to
>accelerate, and the more torque you have the quicker you can
>accelerate.
>
>I stand by my original point - I could not make the overtakes I make
>on the Thunderace if it only made 80 bhp, whatever the revs it made it
>at.
>

But you are doing just that unless you've grafted a DAF transmission
system to your Thunderace.

Your over take is made at 60-70-80-90-100 BHP as you accelerate.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Christopher Des Clayes]

On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> wrote:


>No, sorry. Torque is needed to accelerate. The higher torque, the
>higher the acceleration. Indeed, a definition of torque is 'rotational
>acceleration'.

Do you get your definitions from the same place as Frag?

The units of torque are force times distance. Dimensional analysis
will demonstrate that this is not the same thing as acceleration.

--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Christopher Des Clayes]

On Mon, 10 Jan 2005 11:17:55 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 10 Jan 2005 11:39:07 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>On Sat, 08 Jan 2005 17:18:35 +0000, Colin Irvine
>><Colin.Irvine@spamcop.net> wrote:
>>
>>>On Thu, 6 Jan 2005 22:25:44 +0000,
>>>chateauSPAMKILL.murray@dsl.pipex.com (The Older Gentleman) squeezed
>>>out the following:
>>>
>>>>I have to admit that you're absolutely right.
>>>>
>>>>The number of road (ie: not racers) riders I can think of, who can use
>>>>more than, say 80bhp to its absolute full, on public roads, is....
>>>>
>>>><counts fingers>
>>>>
>>>>Zero.
>>>
>>>I take it you're excluding overtakes up steep hills two-up with
>>>luggage?
>>
>>But that's about torque, not power.
>
>Oh bollox is it. Everyone seems to think torque is about grunt, and
>power is about revs, which while having some basis in truth, is far
>from the full story.
>
>It should be compulsory for everyone to read this article
>http://vettenet.org/torquehp.html before discussing power and torque.

I read it.

The statement:

"Now, it's important to understand that nobody on the planet ever
actually measures horsepower from a running engine. " is absolute and
total bollocks.

Perhaps the writer only has experience of brake dynamometers.

However, there's a lot of good stuff in there.
--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Colin Irvine]

On Mon, 10 Jan 2005 19:24:35 +0000, Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> squeezed out the following:

>In article <04k5u0hvhfngrghn3uqusiuduo3o2mt8kq@4ax.com>, Colin Irvine
><Colin.Irvine@spamcop.net> writes

>>I stand by my original point - I could not make the overtakes I make
>>on the Thunderace if it only made 80 bhp, whatever the revs it made it
>>at.
>>
>
>But you are doing just that unless you've grafted a DAF transmission
>system to your Thunderace.
>
>Your over take is made at 60-70-80-90-100 BHP as you accelerate.

Probably most of the time, yes - but I still need the higher power
eventually. As it is, I tend to drop a gear or two, in which case you
can add a bit to your figures.

If I'm doing 10-12k rpm (or thereabouts) in second past a bus and a
couple of cars uphill in the Alps, with the throttle wide open and
Pat's back hard against the top box, then I'm definitely using a lot
more than 80 bhp. And I wouldn't do that overtake if I couldn't.
That's all I'm saying.

--
Colin Irvine
YZF1000R BOF#33 BONY#34 COFF#06 BHaLC#5
http://www.colin.irvine.dsl.pipex.com/

[Ace]

On Mon, 10 Jan 2005 21:02:47 +0000, Christopher Des Clayes
<Chris@127.0.0.1> wrote:

>On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> wrote:
>
>
>>No, sorry. Torque is needed to accelerate. The higher torque, the
>>higher the acceleration. Indeed, a definition of torque is 'rotational
>>acceleration'.
>
>Do you get your definitions from the same place as Frag?

It wasn't meant to be a scientific definition, hence 'a definition'.
'A' better definition would have been 'rotational force tending to
accelerate.'

>The units of torque are force times distance. Dimensional analysis
>will demonstrate that this is not the same thing as acceleration.

Indeed not. But it takes the place of Force in the normal f=ma
equation, when dealing with rotating masses, hence T=ia(r), i.e. for a
given moment of inertia (==mass) the rotational acceleration is
proportional to the torque applied.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Christopher Des Clayes]

On Tue, 11 Jan 2005 10:41:48 +0100, Ace <b.rogers@virgin.net> wrote:

>On Mon, 10 Jan 2005 21:02:47 +0000, Christopher Des Clayes
><Chris@127.0.0.1> wrote:
>
>>On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> wrote:
>>
>>
>>>No, sorry. Torque is needed to accelerate. The higher torque, the
>>>higher the acceleration. Indeed, a definition of torque is 'rotational
>>>acceleration'.
>>
>>Do you get your definitions from the same place as Frag?
>
>It wasn't meant to be a scientific definition, hence 'a definition'.
>'A' better definition would have been 'rotational force tending to
>accelerate.'
>
>>The units of torque are force times distance. Dimensional analysis
>>will demonstrate that this is not the same thing as acceleration.
>
>Indeed not. But it takes the place of Force in the normal f=ma
>equation, when dealing with rotating masses, hence T=ia(r), i.e. for a
>given moment of inertia (==mass) the rotational acceleration is
>proportional to the torque applied.

No argument with that, just didn't like the sloppy definition above.
--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Richard Wood]

"Ace" <b.rogers@virgin.net> wrote in message news:6d77u01381bi68ul2cci27ge9kubf9islp@4ax.com...
> On Mon, 10 Jan 2005 21:02:47 +0000, Christopher Des Clayes
> <Chris@127.0.0.1> wrote:
>
> >On Mon, 10 Jan 2005 15:30:22 +0100, Ace <b.rogers@virgin.net> wrote:
> >
> >
> >>No, sorry. Torque is needed to accelerate. The higher torque, the
> >>higher the acceleration. Indeed, a definition of torque is 'rotational
> >>acceleration'.
> >
> >Do you get your definitions from the same place as Frag?

<slap>

Thats you off my late xmas card list!

> It wasn't meant to be a scientific definition, hence 'a definition'.
> 'A' better definition would have been 'rotational force tending to
> accelerate.'

Just ignore them all, they're that anally retentive they can't peel themselves
off their collective bike seats without the sound of ripping plastic...



frag

[Simian]

Ace wrote:
>
>>Ok, to go back to the original point - "overtaking up steep hills two
>>up with luggage". A minimum amount of torque is required to get you
>>up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
>>work/time you need power.
>
> No, sorry. Torque is needed to accelerate. The higher torque, the
> higher the acceleration. Indeed, a definition of torque is 'rotational
> acceleration'.

Champ is correct.

Sure, you need torque, but torque is just a by-product of the power
the engine develops.

For example, if I need to increase the torque at the rear wheel of my
bike, I just have to change the gearing, with no modification to the
engine itself.

If bike A makes twice the power of bike B, then bike A will be able
to accellerate at about 1.4 times the rate of bike B, all else being
equal.

--
ZX7RR.

[Ace]

On Thu, 13 Jan 2005 22:39:34 -0000, Simian
<Simian@in_valid.semi-evolved.org> wrote:

>Ace wrote:
>>
>>>Ok, to go back to the original point - "overtaking up steep hills two
>>>up with luggage". A minimum amount of torque is required to get you
>>>up the hill, but to get you up the hill *quickly* (i.e. overtaking) =
>>>work/time you need power.
>>
>> No, sorry. Torque is needed to accelerate. The higher torque, the
>> higher the acceleration. Indeed, a definition of torque is 'rotational
>> acceleration'.
>
>Champ is correct.

So where's you're supporting argument then? C'mon, you can do better
than this.

>Sure, you need torque, but torque is just a by-product of the power
>the engine develops.

Not a by-product at all, just a different way of looking at it. In
fact, one could argue that the opposite is true - power is really
simply the application of torque.

>For example, if I need to increase the torque at the rear wheel of my
>bike, I just have to change the gearing, with no modification to the
>engine itself.

And your point is? By doing so you'll be changing the engine revs and
hence both the power and torque.

>If bike A makes twice the power of bike B, then bike A will be able
>to accellerate at about 1.4 times the rate of bike B, all else being
>equal.

You can't get away from the inherent relationship betwee torque and
power - it's not possible to have one without the other, but the point
in the rev range at which the power is made is hugely significant.

Power developed at high revs, and hence lower torque (remember the
equations - this inverse relationship is true above 5250rpm) will
_not_ accelerate you as quickly.

One only has to ask the question - "what's the best engine speed to
pop a wheelie?" to answer this. It's clearly the point at which the
maximum twisting force (i.e. torque) is available.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Simian]

Ace wrote:
> On Thu, 13 Jan 2005 22:39:34 -0000, Simian
><Simian@in_valid.semi-evolved.org> wrote:
>
>>Champ is correct.
>
> So where's you're supporting argument then? C'mon, you can do better
> than this.

Pushed for time, me.


>>Sure, you need torque, but torque is just a by-product of the power
>>the engine develops.
>
> Not a by-product at all, just a different way of looking at it. In
> fact, one could argue that the opposite is true - power is really
> simply the application of torque.

So petrol contains torque, does it? Don't think so.


It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
75kJ to the bike+rider. A bike with an average power output of 75kJ per
second during the acceleration, will be able to do this in one second.

With an average power of 37kW, it would be able to do it in 2 seconds.

Now, let's equip this bike with a continuously variable gearing, a-la
scooters. It doesn't matter whether it makes that 75kW at 100,000 rpm,
or 100 rpm, the torque at the rear wheel will be exactly the same.

Obvously the torque at the crank will be different, but the torque there
doesn't matter, cos that torque is not touching the road.

Now, where your "power at high revs is crap for accellerating you" comes
from isn't really anything to do with the rpm at which the power is made,
but the width of the power band, and the suitableness of the gearing.

Whoever said "people buy power but ride torque", wasn't really correct,
people buy power, but ride width of powerband. It just happens to be
that a wide spead of power is easier to produce at lower revs than high,
and in order to have any power at lower revs, you need a longer stroke
motor, which will, tan-tan-taaaa, have a higher torque at the crank
(where, of course, it's not important).

--
ZX7RR.

[Mick Whittingham]

In article <10ugeaut7nh996@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Ace wrote:
>> On Thu, 13 Jan 2005 22:39:34 -0000, Simian
>><Simian@in_valid.semi-evolved.org> wrote:
>>
>>>Champ is correct.
>>
>> So where's you're supporting argument then? C'mon, you can do better
>> than this.
>
>Pushed for time, me.
>
>
>>>Sure, you need torque, but torque is just a by-product of the power
>>>the engine develops.
>>
>> Not a by-product at all, just a different way of looking at it. In
>> fact, one could argue that the opposite is true - power is really
>> simply the application of torque.
>
>So petrol contains torque, does it? Don't think so.

Ignited petrol is the source of the pressure on the piston and over the
power stroke, the Mean Effective Pressure is used to calculate the
torque on the crank.
>
>
>It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
>at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
>energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
>75kJ to the bike+rider. A bike with an average power output of 75kJ per
>second during the acceleration, will be able to do this in one second.
>
>With an average power of 37kW, it would be able to do it in 2 seconds.

75kJ is twice 37kW ?

>
>Now, let's equip this bike with a continuously variable gearing, a-la
>scooters. It doesn't matter whether it makes that 75kW at 100,000 rpm,
>or 100 rpm, the torque at the rear wheel will be exactly the same.

William (as did others) once looked to DAF to produce a continuously
variable drive for F1 cars. It meant they could produce high power
sacrificing power & torque band width.
>
>Obvously the torque at the crank will be different, but the torque there
>doesn't matter, cos that torque is not touching the road.
>
>Now, where your "power at high revs is crap for accellerating you" comes
>from isn't really anything to do with the rpm at which the power is made,
>but the width of the power band, and the suitableness of the gearing.

Careful you'll be getting back to torque :-)
>
>Whoever said "people buy power but ride torque", wasn't really correct,
>people buy power, but ride width of powerband.

When torque moves through an angle work is done equal to the product of
the torque and radians turned.
Power is then dependant on the rate at which the angle turns.

Power is therefore a product of torque and the speed of rotation as you
say subject to gearing to alter the torque applied to the road.

>It just happens to be
>that a wide spead of power is easier to produce at lower revs than high,
>and in order to have any power at lower revs, you need a longer stroke
>motor, which will, tan-tan-taaaa, have a higher torque at the crank
>(where, of course, it's not important).
>
Yes but in the real world of engineering it's looked at the other way
around. You compromise obtaining a high horse power by increasing rpm,
which through the inefficiencies of combustion engines has the habit of
reducing the band width of the torque and also the power and bringing
them closer together in actual rpm as the revs increase.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Simian]

Mick Whittingham wrote:
> In article <10ugeaut7nh996@news.supernews.com>, Simian
>>
>>So petrol contains torque, does it? Don't think so.
>
> Ignited petrol is the source of the pressure on the piston and over the
> power stroke, the Mean Effective Pressure is used to calculate the
> torque on the crank.

Yes Mick, I know how it all works.


>>It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
>>at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
>>energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
>>75kJ to the bike+rider. A bike with an average power output of 75kJ per
>>second during the acceleration, will be able to do this in one second.
>>
>>With an average power of 37kW, it would be able to do it in 2 seconds.
>
> 75kJ is twice 37kW ?

Read again: "A bike with an average power output of 75kJ per second"


>>Whoever said "people buy power but ride torque", wasn't really correct,
>>people buy power, but ride width of powerband.
>
> When torque moves through an angle work is done equal to the product of
> the torque and radians turned. Power is then dependant on the rate at
> which the angle turns. Power is therefore a product of torque and the
> speed of rotation as you say subject to gearing to alter the torque
> applied to the road.

You've got it backwards - power comes from burning the petrol at a
certain rate, which is translated to an amount of kinetic energy after
a given time.

Sure, F = MA, and all that, but F /at X mph/ is limited by power. I.e. with
correct gearing, you could give a gc125 the same torque at the rear wheel as
a standard R1, from a standstill, so, very briefly, they would have the same
accelleration.

Try and overtake a 60mph car uphill, and the /power/ of the R1 will make it
possible, and the lack of power of the CG125 will make it impossible.


>>It just happens to be
>>that a wide spead of power is easier to produce at lower revs than high,
>>and in order to have any power at lower revs, you need a longer stroke
>>motor, which will, tan-tan-taaaa, have a higher torque at the crank
>>(where, of course, it's not important).
>>
> Yes but in the real world of engineering it's looked at the other way
> around.

People can look at it any way round they want, if that makes it easier to
think about. It doesn't change the fact that a bike with loads of power,
and gearing to match, will accellerate faster at normal road speeds than
a bike with lower power but a higher peak torque at the crank, no matter
what you do with the gearing of the latter.


--
ZX7RR.

[Richard Wood]

"Simian" <Simian@in_valid.semi-evolved.org> wrote in message news:10ugkc0m576ducb@news.supernews.com...
> Mick Whittingham wrote:
> > In article <10ugeaut7nh996@news.supernews.com>, Simian
> >>
> >>So petrol contains torque, does it? Don't think so.
> >
> > Ignited petrol is the source of the pressure on the piston and over the
> > power stroke, the Mean Effective Pressure is used to calculate the
> > torque on the crank.
>
> Yes Mick, I know how it all works.

<snippity snip>


Can I just say at this moment that I have absolutely no ****in clue what
the difference is between torque and HP apart from torque occurs
lower in the revs and bikes feel good when revving high so I likes
HP more, and the higher the numbers the better...




frag

[Christopher Des Clayes]

On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
wrote:

>"Simian" <Simian@in_valid.semi-evolved.org> wrote in message news:10ugkc0m576ducb@news.supernews.com...
>> Mick Whittingham wrote:
>> > In article <10ugeaut7nh996@news.supernews.com>, Simian
>> >>
>> >>So petrol contains torque, does it? Don't think so.
>> >
>> > Ignited petrol is the source of the pressure on the piston and over the
>> > power stroke, the Mean Effective Pressure is used to calculate the
>> > torque on the crank.
>>
>> Yes Mick, I know how it all works.
>
><snippity snip>
>
>
>Can I just say at this moment that I have absolutely no ****in clue what
>the difference is between torque and HP apart from torque occurs
>lower in the revs and bikes feel good when revving high so I likes
>HP more, and the higher the numbers the better...

The principle is simple. A bit like Ohms Law (Volts = Amps x Ohms).

When you use appropriate matching units (eg the MKS system):

Power = Torque x Revs.



HTH
--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Mick Whittingham]

In article <10ugkc0m576ducb@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Mick Whittingham wrote:
>> In article <10ugeaut7nh996@news.supernews.com>, Simian
>>>
>>>So petrol contains torque, does it? Don't think so.
>>
>> Ignited petrol is the source of the pressure on the piston and over the
>> power stroke, the Mean Effective Pressure is used to calculate the
>> torque on the crank.
>
>Yes Mick, I know how it all works.

?

>
>
>>>It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
>>>at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
>>>energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
>>>75kJ to the bike+rider. A bike with an average power output of 75kJ per
>>>second during the acceleration, will be able to do this in one second.
>>>
>>>With an average power of 37kW, it would be able to do it in 2 seconds.
>>
>> 75kJ is twice 37kW ?
>
>Read again: "A bike with an average power output of 75kJ per second"


1J = 2.7777 times 10 to the -7 kilowatt hours.

>
>
>>>Whoever said "people buy power but ride torque", wasn't really correct,
>>>people buy power, but ride width of powerband.
>>
>> When torque moves through an angle work is done equal to the product of
>> the torque and radians turned. Power is then dependant on the rate at
>> which the angle turns. Power is therefore a product of torque and the
>> speed of rotation as you say subject to gearing to alter the torque
>> applied to the road.
>
>You've got it backwards - power comes from burning the petrol at a
>certain rate, which is translated to an amount of kinetic energy after
>a given time.

?

Actually the basis of every internal or continuous combustion engine is
the amount of air you can pass through it.
The more air passing through that you can heat in an internal combustion
engine the more the MEP is present to do work.
The more MEP the more torque.
Combine that torque with RPM and you have power.

>
>Sure, F = MA, and all that, but F /at X mph/ is limited by power. I.e. with
>correct gearing, you could give a gc125 the same torque at the rear wheel as
>a standard R1, from a standstill, so, very briefly, they would have the same
>accelleration.

Torque without rotation is zero power.
You haven't got any patents on perpetual motion have you? :-)

>
>Try and overtake a 60mph car uphill, and the /power/ of the R1 will make it
>possible, and the lack of power of the CG125 will make it impossible.

The torque and it's ability to deliver it over a usable band width does
it. The CG will have insufficient torque over a wide enough band to
provide the power.
>
>
>>>It just happens to be
>>>that a wide spead of power is easier to produce at lower revs than high,
>>>and in order to have any power at lower revs, you need a longer stroke
>>>motor, which will, tan-tan-taaaa, have a higher torque at the crank
>>>(where, of course, it's not important).
>>>
>> Yes but in the real world of engineering it's looked at the other way
>> around.
>
>People can look at it any way round they want, if that makes it easier to
>think about. It doesn't change the fact that a bike with loads of power,
>and gearing to match, will accellerate faster at normal road speeds than
>a bike with lower power but a higher peak torque at the crank, no matter
>what you do with the gearing of the latter.
>
>
You are comparing eggs with apples as you did above with the CG/R1.
Why not compare two engines with the same maximum HP and one with a
wider lower RPM torque band.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Preston Kemp]

Richard Wood wrote:

> Can I just say at this moment that I have absolutely no ****in clue
> what the difference is between torque and HP apart from torque occurs
> lower in the revs and bikes feel good when revving high so I likes
> HP more, and the higher the numbers the better...

A (very) simplistic explanation. Torque is what makes the wheel turn.
But you can have enough torque to turn a 5000 ton wheel & still not get
anywhere fast unless you turn that wheel at a reasonable rate. For
example container ship engines may have 50,000Nm of torque, but stick
one of those engines in a Class 1 power boat & you ain't gonna win any
races as they rev so slowly.

So what you need to convert all that torque into forward motion is
revolutions - RPM. Combine the two (torque x RPM) & you get 'power'.
The higher the RPM for a given amount of torque, the more power you get.

Except that only holds true up to a certain level. Once you hit that
level, which might be say 8000 RPM for a typical 4 cylinder engine, the
amount of torque being developed starts to drop. However it doesn't
drop as quickly as the RPM increase, so the amount of power being
produced continues to rise.

Eventually the increasing RPM can no longer match the decreasing
torque, so the power starts to drop - time to change gear.

--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[WavyDavy]

"Christopher Des Clayes" <Chris@127.0.0.1> wrote in message
news:ntvhu0h9c6ht372ejc6fovasng2ftovqhf@4ax.com...
> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>

<snip>

>>Can I just say at this moment that I have absolutely no ****in clue what
>>the difference is between torque and HP apart from torque occurs
>>lower in the revs and bikes feel good when revving high so I likes
>>HP more, and the higher the numbers the better...
>
> The principle is simple. A bit like Ohms Law (Volts = Amps x Ohms).
>
> When you use appropriate matching units (eg the MKS system):
>
> Power = Torque x Revs.
>

....divided by 5250

If you don't do the division then, for example, a Triumph Rocket 3 with a
torque figure of 137.6 ftlb-f @ 3200rpm would be producing 440,320bhp at
those revs rather than the actual 83.87bhp it does produce at that point in
the rev range....

Dave

[Christopher Des Clayes]

On Sat, 15 Jan 2005 12:35:03 +0000 (UTC), "WavyDavy"
<dnk.haynes@btinternet.com> wrote:

>
>"Christopher Des Clayes" <Chris@127.0.0.1> wrote in message
>news:ntvhu0h9c6ht372ejc6fovasng2ftovqhf@4ax.com...
>> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
>
><snip>
>
>>>Can I just say at this moment that I have absolutely no ****in clue what
>>>the difference is between torque and HP apart from torque occurs
>>>lower in the revs and bikes feel good when revving high so I likes
>>>HP more, and the higher the numbers the better...
>>
>> The principle is simple. A bit like Ohms Law (Volts = Amps x Ohms).
>>
>> When you use appropriate matching units (eg the MKS system):
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^

Which bit of this didn't you understand?

>>
>> Power = Torque x Revs.
>>
>
>...divided by 5250
>
>If you don't do the division then, for example, a Triumph Rocket 3 with a
>torque figure of 137.6 ftlb-f @ 3200rpm would be producing 440,320bhp at
>those revs rather than the actual 83.87bhp it does produce at that point in
>the rev range....

Inappropriate units, so it becomes P=kTR where in this case k=1/5250.

Satisfied?


--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Christopher Des Clayes]

On Sat, 15 Jan 2005 11:52:41 +0000, Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> wrote:

>The more air passing through that you can heat in an internal combustion
>engine the more the MEP is present to do work.

This would explain a great deal about the European Parliament.

--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Champ]

On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
wrote:

>Can I just say at this moment that I have absolutely no ****in clue what
>the difference is between torque and HP apart from torque occurs
>lower in the revs and bikes feel good when revving high so I likes
>HP more, and the higher the numbers the better...

Everything you know is wrong.

Well, the bit above is.

Most people equate "torque" to "low/mid-range acceleration", and thus
say things like "twins have more torque than fours". Well:

Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
--
Champ

[Verdigris]

On Sat, 15 Jan 2005 11:43:12 +0000, Christopher Des Clayes wrote:

<SNIP>

> The principle is simple. A bit like Ohms Law (Volts = Amps x Ohms).
>
> When you use appropriate matching units (eg the MKS system):
>
> Power = Torque x Revs.

Which just underlines the futility of the whole argument of torque vs
power. Neither one has any particular meaning unless you say at what revs
it occurs, in which case they're directly related and effectively
interchangeable.

The only thing which is of any value is a torque or power curve, and a
power curve is much easier to interpret for most folk because you can
clearly see the increase (and eventual decrease) with revs, which is easy
to relate to the motoring experience.

--
Simon - verdant lineone ne t
Triumph Tiger. Big trailees - you know they make sense.
Z1000 - less sense, more sensation.
MAG BOTAFOT#36 two#22 HLR#pi BONY#62 BHaLC#3

[WavyDavy]

"Christopher Des Clayes" <Chris@127.0.0.1> wrote in message
news:9d4iu0tair8bri8v4jl316pc60kn5ls4a1@4ax.com...
> On Sat, 15 Jan 2005 12:35:03 +0000 (UTC), "WavyDavy"
> <dnk.haynes@btinternet.com> wrote:
>
>>
>>"Christopher Des Clayes" <Chris@127.0.0.1> wrote in message
>>news:ntvhu0h9c6ht372ejc6fovasng2ftovqhf@4ax.com...
>>> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
>>
>><snip>
>>
>>>>Can I just say at this moment that I have absolutely no ****in clue what
>>>>the difference is between torque and HP apart from torque occurs
>>>>lower in the revs and bikes feel good when revving high so I likes
>>>>HP more, and the higher the numbers the better...
>>>
>>> The principle is simple. A bit like Ohms Law (Volts = Amps x Ohms).
>>>
>>> When you use appropriate matching units (eg the MKS system):
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^
>
> Which bit of this didn't you understand?

The bit that describes the 'MKS System', tbh (no underlining necessary).

>>>
>>> Power = Torque x Revs.
>>>
>>
>>...divided by 5250
>>
>>If you don't do the division then, for example, a Triumph Rocket 3 with a
>>torque figure of 137.6 ftlb-f @ 3200rpm would be producing 440,320bhp at
>>those revs rather than the actual 83.87bhp it does produce at that point
>>in
>>the rev range....
>
> Inappropriate units, so it becomes P=kTR where in this case k=1/5250.

Inappropriate poncyness. I just added something to make your equation more
accessible to those of us who talk in plain English.

> Satisfied?

No.

[Simian]

Mick Whittingham wrote:
>>>>It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
>>>>at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
>>>>energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
>>>>75kJ to the bike+rider. A bike with an average power output of 75kJ per
>>>>second during the acceleration, will be able to do this in one second.
>>>>
>>>>With an average power of 37kW, it would be able to do it in 2 seconds.
>>>
>>> 75kJ is twice 37kW ?
>>
>>Read again: "A bike with an average power output of 75kJ per second"
>
>
> 1J = 2.7777 times 10 to the -7 kilowatt hours.

We're talking about power you numpty.

1 joule per second = one watt

By definition.

1kJ produced in one second is 1kW.

75kj/s = 75kW.

One half of 75kj/s = 37.5kj/s = 37.5kW, I just left of the half cos
it wasn't important.

Technically, the equals signs should be equivalences for most of that,
but my keyboard aint got one of those.


>>You've got it backwards - power comes from burning the petrol at a
>>certain rate, which is translated to an amount of kinetic energy after
>>a given time.
>
> ?
>
> Actually the basis of every internal or continuous combustion engine is
> the amount of air you can pass through it.

Yes, you use the air to burn the petrol, for a start.


> The more air passing through that you can heat in an internal combustion
> engine the more the MEP is present to do work.

It takes energy to heat up the air, the more air per second that you want to
heat up, the more energy per second you need to use, i.e. the more power you
need.


> You are comparing eggs with apples as you did above with the CG/R1.
> Why not compare two engines with the same maximum HP and one with a
> wider lower RPM torque band.

I did - give them continuously variable transmission, and there will
be no difference. Take non-perfect gearing into account, and the width
of the power band becomes important.

So, lets take power band width out of the equation. Say the two engines
make the same peak power (lets say 100bhp) and one makes it at 5000rpm,
dropping to 90bhp at 4000rpm, and again dropping to 90 at 6000 rpm, and
the other makes peak at 9000 rpm, and drops to 90bhp at 8000, and again
at 10,000.

Obviously the first bike will produce a lot more torque at the crank than
the first one, but give each bike gearing that drops 2000rpm per change,
and sits them at the bottom of their power band (5000, and 8000rpm respectively)
at the start of the accelleration, they will accellerate at the same rate.

The ability to accelerate from one speed to another is governed by the power
you are able to produce, and the suitability of the gearing to your power
band.

--
ZX7RR.

[Mick Whittingham]

In article <10uj16i8d3e5133@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Mick Whittingham wrote:
>>>>>It's pretty simple really, 75Kg rider, 175Kg bike, 250Kg total, traveling
>>>>>at 20mph, has a kinetic energy of about 25kJ. Traveling at 40mph, a kinetic
>>>>>energy of about 100kJ. To accelerate from 20, to 40mph, you need to add
>>>>>75kJ to the bike+rider. A bike with an average power output of 75kJ per
>>>>>second during the acceleration, will be able to do this in one second.
>>>>>
>>>>>With an average power of 37kW, it would be able to do it in 2 seconds.
>>>>
>>>> 75kJ is twice 37kW ?
>>>
>>>Read again: "A bike with an average power output of 75kJ per second"
>>
>>
>> 1J = 2.7777 times 10 to the -7 kilowatt hours.
>
>We're talking about power you numpty.

I think you referred to 75kJ hence my notation, not
75kJ/s which of course is power.
>
>1 joule per second = one watt
>
>By definition.
>
>1kJ produced in one second is 1kW.
>
>75kj/s = 75kW.
>
>One half of 75kj/s = 37.5kj/s = 37.5kW, I just left of the half cos
>it wasn't important.
>
>Technically, the equals signs should be equivalences for most of that,
>but my keyboard aint got one of those.

Notice you've include the /s in now :-)
>
>
>>>You've got it backwards - power comes from burning the petrol at a
>>>certain rate, which is translated to an amount of kinetic energy after
>>>a given time.
>>
>> ?
>>
>> Actually the basis of every internal or continuous combustion engine is
>> the amount of air you can pass through it.
>
>Yes, you use the air to burn the petrol, for a start.
>
>
>> The more air passing through that you can heat in an internal combustion
>> engine the more the MEP is present to do work.
>
>It takes energy to heat up the air, the more air per second that you want to
>heat up, the more energy per second you need to use, i.e. the more power you
>need.

I think we need to look into the reason behind 4 and 5 valve heads
before you make statements like that.
>
>
>> You are comparing eggs with apples as you did above with the CG/R1.
>> Why not compare two engines with the same maximum HP and one with a
>> wider lower RPM torque band.
>
>I did - give them continuously variable transmission, and there will
>be no difference. Take non-perfect gearing into account, and the width
>of the power band becomes important.
>
>So, lets take power band width out of the equation. Say the two engines
>make the same peak power (lets say 100bhp) and one makes it at 5000rpm,
>dropping to 90bhp at 4000rpm, and again dropping to 90 at 6000 rpm, and
>the other makes peak at 9000 rpm, and drops to 90bhp at 8000, and again
>at 10,000.

????

>
>Obviously the first bike will produce a lot more torque at the crank than
>the first one, but give each bike gearing that drops 2000rpm per change,
>and sits them at the bottom of their power band (5000, and 8000rpm
>respectively)
>at the start of the accelleration, they will accellerate at the same rate.
>

With this bit:
>The ability to accelerate from one speed to another is governed by the power
>you are able to produce, and the suitability of the gearing to your power
>band.
>
I rest may case.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Simian]

Mick Whittingham wrote:
> In article <10uj16i8d3e5133@news.supernews.com>, Simian
>
>>>>>>A bike with an average power output of 75kJ per
>>>>>>second during the acceleration
>>>>>>
>>
>>We're talking about power you numpty.
>
> I think you referred to 75kJ hence my notation, not
> 75kJ/s which of course is power.
> Notice you've include the /s in now :-)

Look at the very first two lines of quoted content above. Notice the 'per second'
Notice that this is equivalent to putting /s in the units. Notice that I pointed
this out in my last post as well.


>>It takes energy to heat up the air, the more air per second that you want to
>>heat up, the more energy per second you need to use, i.e. the more power you
>>need.
>
> I think we need to look into the reason behind 4 and 5 valve heads
> before you make statements like that.

The various designs of head are there to produce optimal power curves
for the intended application, and its charge mass velocity.


> With this bit:
>>The ability to accelerate from one speed to another is governed by the power
>>you are able to produce, and the suitability of the gearing to your power
>>band.
>>
> I rest may case.

But you haven't made one.

Ace was saying that torque was important, not power, all I've said is
is that power and it's spread and gearing is the actual important thing.

The width of the power band doesn't care about torque. You can have 100bhp
across a 1000rpm power band centred on 5000, or 50,000rpm, with a ten-fold
difference in torque (at the crank) and the ability to accellerate is the same,
because you have the same power, and spread, and (you'd hope) apropriateness
of gearing.

Sure, designing a reciprocating internal combustion engine with a wide spread
of power at lower revs is easier than designing one with the same characteristics
at high revs (just make the engine bigger), but one shouldn't get hung up on
the restrictions of designing an affordable motorbike when thinking about what
gives a bike the ability to accellerate.

--
ZX7RR.

[Gunga Dan]

Champ <news@champ.org.uk> wrote

> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
> wrote:
>
>>Can I just say at this moment that I have absolutely no ****in clue what
>>the difference is between torque and HP apart from torque occurs
>>lower in the revs and bikes feel good when revving high so I likes
>>HP more, and the higher the numbers the better...
>
> Everything you know is wrong.
>
> Well, the bit above is.
>
> Most people equate "torque" to "low/mid-range acceleration", and thus
> say things like "twins have more torque than fours". Well:
>
> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm

Yes but how about comparing the torque outputs of two bikes with similar
peak power outputs. I think it's more to do with twins having more torque
relative to the amount of power they produce which makes people describe as
'torquey'.

[Salad Dodger]

On 15 Jan 2005 23:41:45 GMT, Gunga Dan <dedge12858@nothotmail.com>
wrote:

>Champ <news@champ.org.uk> wrote
>
>> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
>> wrote:
>>
>>>Can I just say at this moment that I have absolutely no ****in clue what
>>>the difference is between torque and HP apart from torque occurs
>>>lower in the revs and bikes feel good when revving high so I likes
>>>HP more, and the higher the numbers the better...
>>
>> Everything you know is wrong.
>>
>> Well, the bit above is.
>>
>> Most people equate "torque" to "low/mid-range acceleration", and thus
>> say things like "twins have more torque than fours". Well:
>>
>> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
>
>Yes but how about comparing the torque outputs of two bikes with similar
>peak power outputs. I think it's more to do with twins having more torque
>relative to the amount of power they produce which makes people describe as
>'torquey'.

What about flat sixes, eh?

IDSTR the CB125T I took my test on as being particularly "torquey",
either.

--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SEV/CBR1100XXX/KH500A8/TS250C
|_\_____/_| ..73066../..17485.../..3184./.19406
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4 PM#5
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11 WG*
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17 IbB#4
'^'

[Gunga Dan]

Salad Dodger <salad.dodger@gmail.com> wrote

> On 15 Jan 2005 23:41:45 GMT, Gunga Dan <dedge12858@nothotmail.com>
> wrote:

<twins/fours>

>>Champ <news@champ.org.uk> wrote

>>> Most people equate "torque" to "low/mid-range acceleration", and thus
>>> say things like "twins have more torque than fours". Well:
>>>
>>> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>>> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
>>
>>Yes but how about comparing the torque outputs of two bikes with
>>similar peak power outputs. I think it's more to do with twins having
>>more torque relative to the amount of power they produce which makes
>>people describe as 'torquey'.
>
> What about flat sixes, eh?

You have to rev the tits off them to make them go apparently...

> IDSTR the CB125T I took my test on as being particularly "torquey",
> either.

But it might feel torquier than a '4' with similar power output - if there
is such a thing.

[Mick Whittingham]

In article <10uj776nkg6ipac@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Mick Whittingham wrote:
>> In article <10uj16i8d3e5133@news.supernews.com>, Simian
>>
>>>>>>>A bike with an average power output of 75kJ per
>>>>>>>second during the acceleration
>>>>>>>
>>>
>>>We're talking about power you numpty.
>>
>> I think you referred to 75kJ hence my notation, not
>> 75kJ/s which of course is power.
>> Notice you've include the /s in now :-)
>
>Look at the very first two lines of quoted content above. Notice the
>'per second'
>Notice that this is equivalent to putting /s in the units. Notice that
>I pointed
>this out in my last post as well.

Re-reads post.
OK let you have that one:-)
I'm speed reading this stuff.
>
>
>>>It takes energy to heat up the air, the more air per second that you want to
>>>heat up, the more energy per second you need to use, i.e. the more power you
>>>need.
>>
>> I think we need to look into the reason behind 4 and 5 valve heads
>> before you make statements like that.
>
>The various designs of head are there to produce optimal power curves
>for the intended application, and its charge mass velocity.

Large total valve area and lift mean less restriction to air flow.
ie more air.
>
>
>> With this bit:
>>>The ability to accelerate from one speed to another is governed by the power
>>>you are able to produce, and the suitability of the gearing to your power
>>>band.
>>>
>> I rest may case.
>
>But you haven't made one.
I'm using your case.

>
>Ace was saying that torque was important, not power, all I've said is
>is that power and it's spread and gearing is the actual important thing.

Power is derived from torque.

>
>The width of the power band doesn't care about torque.

But the power curve is derived from the torque times the revs, they are
linked.

>You can have 100bhp
>across a 1000rpm power band centred on 5000, or 50,000rpm, with a ten-fold
>difference in torque (at the crank) and the ability to accellerate is the same,
>because you have the same power, and spread, and (you'd hope) apropriateness
>of gearing.

I've got an engine with an almost flat horizontal torque 'curve', it
makes the power output a straight line.

>
>Sure, designing a reciprocating internal combustion engine with a wide spread
>of power at lower revs is easier than designing one with the same
>characteristics
>at high revs (just make the engine bigger),

This is true.


>but one shouldn't get hung up on
>the restrictions of designing an affordable motorbike when thinking about what
>gives a bike the ability to accellerate.
>
This is something completely different affordability and acceleration.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Steve Uzochukwu]

On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
wildly wibbled thus:

>"Simian" <Simian@in_valid.semi-evolved.org> wrote in message news:10ugkc0m576ducb@news.supernews.com...
>> Mick Whittingham wrote:
>> > In article <10ugeaut7nh996@news.supernews.com>, Simian
>> >>
>> >>So petrol contains torque, does it? Don't think so.
>> >
>> > Ignited petrol is the source of the pressure on the piston and over the
>> > power stroke, the Mean Effective Pressure is used to calculate the
>> > torque on the crank.
>>
>> Yes Mick, I know how it all works.
>
><snippity snip>
>
>
>Can I just say at this moment that I have absolutely no ****in clue what
>the difference is between torque and HP apart from torque occurs
>lower in the revs and bikes feel good when revving high so I likes
>HP more, and the higher the numbers the better...
>

Not the owner of a direct injectrion diesel then?


--
Steve Uzochukwu, Avian Amour and Windtech Quarx.
http://www.steveu.org/
The UKRM FAQ: http://www.ukrm.net/faq/index.html
************************************************** *************

[Preston Kemp]

Champ wrote:

> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
> wrote:
>
> > Can I just say at this moment that I have absolutely no ****in clue
> > what the difference is between torque and HP apart from torque
> > occurs lower in the revs and bikes feel good when revving high so I
> > likes HP more, and the higher the numbers the better...
>
> Everything you know is wrong.
>
> Well, the bit above is.
>
> Most people equate "torque" to "low/mid-range acceleration", and thus
> say things like "twins have more torque than fours". Well:
>
> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm

Those figures only show peak torque though. I bet it's a different
story at say 3000 rpm, where the TL probably does have more torque than
the gixer. The TL's not really a good comparison either as it's tuned
more for outright power rather than the low-down grunt generally
associated with v-twins. I suspect a similar sized cruiser would
thoroughly shame a gixer at 2,500 rpm.

--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Champ]

On Sun, 16 Jan 2005 00:18:47 GMT, "Preston Kemp"
<dontwantany@nowhere.invalid> wrote:

>> Most people equate "torque" to "low/mid-range acceleration", and thus
>> say things like "twins have more torque than fours". Well:
>>
>> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
>
>Those figures only show peak torque though. I bet it's a different
>story at say 3000 rpm, where the TL probably does have more torque than
>the gixer. The TL's not really a good comparison either as it's tuned
>more for outright power rather than the low-down grunt generally
>associated with v-twins. I suspect a similar sized cruiser would
>thoroughly shame a gixer at 2,500 rpm.

I think you've just made my point for me. When people say "torquey",
they mean, "makes more torque than I expected at low revs"
--
Champ

[Verdigris]

On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:

> Champ <news@champ.org.uk> wrote
<SNIP>

>> Most people equate "torque" to "low/mid-range acceleration", and thus
>> say things like "twins have more torque than fours". Well:
>>
>> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm Suzuki GSX-R 1000:
>> 83.3 ft.lbs of torque at 8400 rpm
>
> Yes but how about comparing the torque outputs of two bikes with similar
> peak power outputs. I think it's more to do with twins having more torque
> relative to the amount of power they produce which makes people describe
> as 'torquey'.

No it isn't. You can't have "more torque relative to the amount of power
they produce", because one is directly proportional to the other. Only
the curve is meaningful.

--
Simon - verdant lineone ne t
Triumph Tiger. Big trailees - you know they make sense.
Z1000 - less sense, more sensation.
MAG BOTAFOT#36 two#22 HLR#pi BONY#62 BHaLC#3

[Preston Kemp]

Verdigris wrote:

> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
>
> > Champ <news@champ.org.uk> wrote
> <SNIP>
>
> >> Most people equate "torque" to "low/mid-range acceleration", and
> thus >> say things like "twins have more torque than fours". Well:
> >>
> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm Suzuki GSX-R
> 1000: >> 83.3 ft.lbs of torque at 8400 rpm
> >
> > Yes but how about comparing the torque outputs of two bikes with
> > similar peak power outputs. I think it's more to do with twins
> > having more torque relative to the amount of power they produce
> > which makes people describe as 'torquey'.
>
> No it isn't. You can't have "more torque relative to the amount of
> power they produce", because one is directly proportional to the
> other.

Have to disagree with that. If you've got two bikes both making 120bhp
peak, one at 12000 rpm & one at 8000 rpm, the latter must be making
more torque relative to it's power output.


--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Bear]

In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ says...
> On Sun, 16 Jan 2005 00:18:47 GMT, "Preston Kemp"
> <dontwantany@nowhere.invalid> wrote:
>
> >> Most people equate "torque" to "low/mid-range acceleration", and thus
> >> say things like "twins have more torque than fours". Well:
> >>
> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
> >> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
> >
> >Those figures only show peak torque though. I bet it's a different
> >story at say 3000 rpm, where the TL probably does have more torque than
> >the gixer. The TL's not really a good comparison either as it's tuned
> >more for outright power rather than the low-down grunt generally
> >associated with v-twins. I suspect a similar sized cruiser would
> >thoroughly shame a gixer at 2,500 rpm.
>
> I think you've just made my point for me. When people say "torquey",
> they mean, "makes more torque than I expected at low revs"

Is the "way" in which it's made a factor too?

In other words, twins give you 2 pulses of power/torque per complete
phase, so it *feels* "thunk thunk" like, whereas a four makes 4 smaller
pulses in the same time frame?

Or not.

Oh ... wibbleflipdibbledoo.
--
Bear
"Don't believe the hype"
Today's music: Miles Davis "Kind Of Blue"

[wessie]

Bear emerged from their own little world to say

> In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ says...

>> I think you've just made my point for me. When people say "torquey",
>> they mean, "makes more torque than I expected at low revs"
>
> Is the "way" in which it's made a factor too?
>
> In other words, twins give you 2 pulses of power/torque per complete
> phase, so it *feels* "thunk thunk" like, whereas a four makes 4 smaller
> pulses in the same time frame?

that's the theory behind the big bangbang-uh-bangbang engine isn't it?

> Or not.
>
> Oh ... wibbleflipdibbledoo.

possibly

--
BMW R1150GS

[Verdigris]

On Sun, 16 Jan 2005 01:13:12 +0000, Preston Kemp wrote:

> Verdigris wrote:
>
>> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
>>
>> > Champ <news@champ.org.uk> wrote
>> <SNIP>
>>
>> >> Most people equate "torque" to "low/mid-range acceleration", and
>> thus >> say things like "twins have more torque than fours". Well:
>> >>
>> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm Suzuki GSX-R
>> 1000: >> 83.3 ft.lbs of torque at 8400 rpm
>> >
>> > Yes but how about comparing the torque outputs of two bikes with
>> > similar peak power outputs. I think it's more to do with twins having
>> > more torque relative to the amount of power they produce which makes
>> > people describe as 'torquey'.
>>
>> No it isn't. You can't have "more torque relative to the amount of
>> power they produce", because one is directly proportional to the other.
>
> Have to disagree with that. If you've got two bikes both making 120bhp
> peak, one at 12000 rpm & one at 8000 rpm, the latter must be making more
> torque relative to it's power output.

That's just fiddling with the numbers. Torque and power *are* directly
related to one another.

--
Simon - verdant lineone ne t
Triumph Tiger. Big trailees - you know they make sense.
Z1000 - less sense, more sensation.
MAG BOTAFOT#36 two#22 HLR#pi BONY#62 BHaLC#3

[Preston Kemp]

Bear wrote:

> In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ says...
> >
> > I think you've just made my point for me. When people say
> > "torquey", they mean, "makes more torque than I expected at low
> > revs"
>
> Is the "way" in which it's made a factor too?
>
> In other words, twins give you 2 pulses of power/torque per complete
> phase, so it feels "thunk thunk" like, whereas a four makes 4 smaller
> pulses in the same time frame?

Sheesh, there's enough confusion when just dealing with the facts,
without throwing people's perception into the mix too! It's an
interesting point though. If you're talking about the extra low-down
acceleration from a twin, you'd think a four would feel faster as you
get twice as many power strokes per revolution (leaving 'big bang'
engines out of the equation). So either there is a bit of a "thunk
thunk" feeling going on, or each power stroke on the multi is less than
half the torque of those on the twin. Or something.


--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Bear]

In article <Xns95E010159996123ert@130.133.1.4>, wessie says...
> Bear emerged from their own little world to say
>
> > In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ says...
>
> >> I think you've just made my point for me. When people say "torquey",
> >> they mean, "makes more torque than I expected at low revs"
> >
> > Is the "way" in which it's made a factor too?
> >
> > In other words, twins give you 2 pulses of power/torque per complete
> > phase, so it *feels* "thunk thunk" like, whereas a four makes 4 smaller
> > pulses in the same time frame?
>
> that's the theory behind the big bangbang-uh-bangbang engine isn't it?

I believe so; the way it was expressed to me was that it takes a large
force to start to move an object against friction, but a smaller one to
maintain it, like pushing a heavy box across a carpet (takes a real heft
to start it moving, but it will continue to move with a smaller force if
applied constantly ... as soon as the force abates the box grips again)
.... so the "bang, bang" approach means the tyre has time to grip again
between pulses, whereas a 4 smaller pulse approach means the tyre starts
to slide, then is kept "topped up" for sliding force by the small but
frequent pulses.

None of which really has much to do with any discussion of power or
torque, but it did allow me to trot out the one bit of am-phys I know
.... now I've got that out of the way I can return to a normal life ...

> > Or not.
> >
> > Oh ... wibbleflipdibbledoo.
>
> possibly

I knew what I meant, but sadly had neither the knowledge nor the
conviction to carry it through ... so I'm bailing.
--
Bear
"Don't believe the hype"
Today's music: Miles Davis "Kind Of Blue"

[Preston Kemp]

wessie wrote:

> Bear emerged from their own little world to say
>
> > In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ
> > says...
>
> >> I think you've just made my point for me. When people say
> "torquey", >> they mean, "makes more torque than I expected at low
> revs"
> >
> > Is the "way" in which it's made a factor too?
> >
> > In other words, twins give you 2 pulses of power/torque per
> > complete phase, so it feels "thunk thunk" like, whereas a four
> > makes 4 smaller pulses in the same time frame?
>
> that's the theory behind the big bangbang-uh-bangbang engine isn't it?

Not really, they're designed to give the rear tyre a rest by doubling
the time between power strokes.

--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Preston Kemp]

Verdigris wrote:

> On Sun, 16 Jan 2005 01:13:12 +0000, Preston Kemp wrote:
>
> > Verdigris wrote:
> >
> >> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
> >>
> >> > Yes but how about comparing the torque outputs of two bikes with
> >> > similar peak power outputs. I think it's more to do with twins
> having >> > more torque relative to the amount of power they produce
> which makes >> > people describe as 'torquey'.
> >>
> >> No it isn't. You can't have "more torque relative to the amount of
> >> power they produce", because one is directly proportional to the
> other.
> >
> > Have to disagree with that. If you've got two bikes both making
> > 120bhp peak, one at 12000 rpm & one at 8000 rpm, the latter must be
> > making more torque relative to it's power output.
>
> That's just fiddling with the numbers. Torque and power are directly
> related to one another.

Well yes, but only within the same engine. Gunga Dan's point about the
relative torque between different bikes still holds true.

--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Verdigris]

On Sun, 16 Jan 2005 01:50:32 +0000, Preston Kemp wrote:

> Verdigris wrote:
>
>> On Sun, 16 Jan 2005 01:13:12 +0000, Preston Kemp wrote:
>>
>> > Verdigris wrote:
>> >
>> >> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
>> >>
>> >> > Yes but how about comparing the torque outputs of two bikes with
>> >> > similar peak power outputs. I think it's more to do with twins
>> having >> > more torque relative to the amount of power they produce
>> which makes >> > people describe as 'torquey'.
>> >>
>> >> No it isn't. You can't have "more torque relative to the amount of
>> >> power they produce", because one is directly proportional to the
>> other.
>> >
>> > Have to disagree with that. If you've got two bikes both making 120bhp
>> > peak, one at 12000 rpm & one at 8000 rpm, the latter must be making
>> > more torque relative to it's power output.
>>
>> That's just fiddling with the numbers. Torque and power are directly
>> related to one another.
>
> Well yes, but only within the same engine. Gunga Dan's point about the
> relative torque between different bikes still holds true.

But you might just as usefully talk about power instead, and neither one
is of the slightest use unless you see the full curve over the operating
rev range. And if you want to look at a graph, power against revs is much
more useful than torque against revs.

--
Simon - verdant lineone ne t
Triumph Tiger. Big trailees - you know they make sense.
Z1000 - less sense, more sensation.
MAG BOTAFOT#36 two#22 HLR#pi BONY#62 BHaLC#3

[Richard Wood]

"Champ" <news@champ.org.uk> wrote in message news:lkgiu0lqusio9frbjv88t9oagcms6v5an2@4ax.com...
> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
> wrote:
>
> >Can I just say at this moment that I have absolutely no ****in clue what
> >the difference is between torque and HP apart from torque occurs
> >lower in the revs and bikes feel good when revving high so I likes
> >HP more, and the higher the numbers the better...
>
> Everything you know is wrong.

Been reading through the "Woods 100% complete mind dump"?

> Well, the bit above is.

"feel good", "I likes", they're my opinions, they don't have right or
wrongs.

> Most people equate "torque" to "low/mid-range acceleration", and thus
> say things like "twins have more torque than fours". Well:

The ZZR1100 has a flattish power curve. Yes it pulled well from low revs
but was a tad boring. The ZX9R has a lot more "lumpy"... er "pronounced"
.... err "it went up lots at the end" power curve and was a lot more exciting
bike to ride from a power delivery point of view (and not just because it
weighed a lot less).

I suppose if you're a courier or on a bike for hours every day then
"low/mid-range acceleration" is good. Why do you have a Gixxer Thou?


frag

[Richard Wood]

"Steve Uzochukwu" <randombloke@genie.co.uk> wrote in message news:41e9b236.56947543@News.Individual.NET...
> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
> wildly wibbled thus:
>
> >Can I just say at this moment that I have absolutely no ****in clue what
> >the difference is between torque and HP apart from torque occurs
> >lower in the revs and bikes feel good when revving high so I likes
> >HP more, and the higher the numbers the better...
>
> Not the owner of a direct injectrion diesel then?

I'm with JC on diesels...



frag

[Champ]

On Sun, 16 Jan 2005 01:28:14 -0000, Bear <bastardDOTbear@gmail.com>
wrote:

>> >> Most people equate "torque" to "low/mid-range acceleration", and thus
>> >> say things like "twins have more torque than fours". Well:
>> >>
>> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>> >> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
>> >
>> >Those figures only show peak torque though. I bet it's a different
>> >story at say 3000 rpm, where the TL probably does have more torque than
>> >the gixer. The TL's not really a good comparison either as it's tuned
>> >more for outright power rather than the low-down grunt generally
>> >associated with v-twins. I suspect a similar sized cruiser would
>> >thoroughly shame a gixer at 2,500 rpm.
>>
>> I think you've just made my point for me. When people say "torquey",
>> they mean, "makes more torque than I expected at low revs"
>
>Is the "way" in which it's made a factor too?
>
>In other words, twins give you 2 pulses of power/torque per complete
>phase, so it *feels* "thunk thunk" like, whereas a four makes 4 smaller
>pulses in the same time frame?

Unless you're talking about the "big bang" effect [1], then I don#t
think so - unless the seat of your pants is able to distinguish
between 2 big bangs and four smaller bangs many 1000 times a minute.
5000rpm is 83rpm per second,y'know.

[1] which is about changing the fireing order to allow the rear tyre
to recover between power pulses
--
Champ

[Mick Whittingham]

In article <pan.2005.01.16.01.34.14.862363@deadspam.com>, Verdigris
<verdigris@deadspam.com> writes
>On Sun, 16 Jan 2005 01:13:12 +0000, Preston Kemp wrote:
>
>> Verdigris wrote:
>>
>>> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
>>>
>>> > Champ <news@champ.org.uk> wrote
>>> <SNIP>
>>>
>>> >> Most people equate "torque" to "low/mid-range acceleration", and
>>> thus >> say things like "twins have more torque than fours". Well:
>>> >>
>>> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm Suzuki GSX-R
>>> 1000: >> 83.3 ft.lbs of torque at 8400 rpm
>>> >
>>> > Yes but how about comparing the torque outputs of two bikes with
>>> > similar peak power outputs. I think it's more to do with twins having
>>> > more torque relative to the amount of power they produce which makes
>>> > people describe as 'torquey'.
>>>
>>> No it isn't. You can't have "more torque relative to the amount of
>>> power they produce", because one is directly proportional to the other.
>>
>> Have to disagree with that. If you've got two bikes both making 120bhp
>> peak, one at 12000 rpm & one at 8000 rpm, the latter must be making more
>> torque relative to it's power output.
>
>That's just fiddling with the numbers. Torque and power *are* directly
>related to one another.
>

I think that's what he said.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Mick Whittingham]

In article <MPG.1c53d6f416ffc8fd989b58@News.individual.net>, Bear
<bastardDOTbear@gmail.com> writes
>In article <Xns95E010159996123ert@130.133.1.4>, wessie says...
>> Bear emerged from their own little world to say
>>
>> > In article <s6eju01df245g428o5j169ellp3npfi54a@4ax.com>, Champ says...


>
>I believe so; the way it was expressed to me was that it takes a large
>force to start to move an object against friction, but a smaller one to
>maintain it, like pushing a heavy box across a carpet (takes a real heft
>to start it moving, but it will continue to move with a smaller force if
>applied constantly ... as soon as the force abates the box grips again)
>... so the "bang, bang" approach means the tyre has time to grip again
>between pulses, whereas a 4 smaller pulse approach means the tyre starts
>to slide, then is kept "topped up" for sliding force by the small but
>frequent pulses.
Wot you said plus:
The most successful power combination on a four was developed with a
specific tyre in mind and was the soft big bang.

BANG
2 BANGS together
BANG

All within a narrow angle of crank rotation so the bangs over lapped.
>
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Simian]

Mick Whittingham wrote:
> Re-reads post.
> OK let you have that one:-)
> I'm speed reading this stuff.

That's OK, I'm speed writing it.


>>The various designs of head are there to produce optimal power curves
>>for the intended application, and its charge mass velocity.
>
> Large total valve area and lift mean less restriction to air flow.
> ie more air.

More air to burn more petrol.

In fact that's not really true, because in a normal bike engine,
you're not coping with restricted air flow, but restricted flow
of fuel/air mixture.

You want bigger valves to let more chemical energy into the cylinder,
to power your bike, not to let more torque in, nor to let more 'air'
in.


>>Ace was saying that torque was important, not power, all I've said is
>>is that power and it's spread and gearing is the actual important thing.
>
> Power is derived from torque.

Power is derived from the rate you burn petrol, the amount of power made
by an engine may be measured by the torque it produces at an angular velocity,
if you want, but you can measure it in other ways.


--
ZX7RR.

[Mick Whittingham]

In article <10ukrpdc7cgpo29@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Mick Whittingham wrote:


>> Large total valve area and lift mean less restriction to air flow.
>> ie more air.
>
>More air to burn more petrol.
>
>In fact that's not really true, because in a normal bike engine,
>you're not coping with restricted air flow, but restricted flow
>of fuel/air mixture.

Fuel is a much smaller percentage of the total so the major concern is
getting air moved. Up to 1 part in 17 in a lean burn engine.
>
>You want bigger valves to let more chemical energy into the cylinder,
>to power your bike,
What if you had direct injection. Some believe its the way to go for
higher efficiencies and greater power for engine mass, be it 2 or 4
stroke.

>not to let more torque in,
I never said that did I?

> nor to let more 'air'
>in.

??????????????
>
>
>>>Ace was saying that torque was important, not power, all I've said is
>>>is that power and it's spread and gearing is the actual important thing.
>>
>> Power is derived from torque.
>
>Power is derived from the rate you burn petrol,
No it is not, that totally ignores engine efficiency.

>the amount of power made
>by an engine may be measured by the torque it produces at an angular velocity,
>if you want,
YES, YES, YES (Did you ever see 'When Harry met Sally'?)

>but you can measure it in other ways.
>
>
Go on then you know you want to......................... :-)
--
Best regards
Mick Whittingham

[steve auvache]

Salad Dodger wrote
>IDSTR the CB125T I took my test on as being particularly "torquey",
>either.

Wouldn't that be affected by being at the bottom of a localised gravity
well though? Time dilation effects and stuff?



--
steve auvache
MZ TS150: for sale still.
Bandit 600

[Salad Dodger]

On Sun, 16 Jan 2005 20:16:24 +0000, steve auvache
<dont_spam@thecow.me.uk> wrote:

>Salad Dodger wrote
>>IDSTR the CB125T I took my test on as being particularly "torquey",
>>either.
>
>Wouldn't that be affected by being at the bottom of a localised gravity
>well though? Time dilation effects and stuff?

Sod off. I wozza svelte young thing, I was.

--
| ___ Salad Dodger
|/ \
_/_____\_ GL1500SEV/CBR1100XXX/KH500A8/TS250C
|_\_____/_| ..73066../..17485.../..3184./.19406
(>|_|_|<) TPPFATUICG#7 DIAABTCOD#9 YTC#4 PM#5
|__|_|__| BOTAFOT #70 BOTAFOF #09 two#11 WG*
\ |^| / IbW#0 & KotIbW# BotTOS#6 GP#4
\|^|/ ANORAK#17 IbB#4
'^'

[Simian]

Mick Whittingham wrote:
>>
>>More air to burn more petrol.
>>
>>In fact that's not really true, because in a normal bike engine,
>>you're not coping with restricted air flow, but restricted flow
>>of fuel/air mixture.
>
> Fuel is a much smaller percentage of the total so the major concern is
> getting air moved. Up to 1 part in 17 in a lean burn engine.

1Kg of petrol requres 14.6Kg of air to burn completely. Generally, most
motorbikes run a little rich, 1 part in 12 or 13, rather than perfect
stoichiometric 1:14.6, so they actually have _less_ air in them than
you'd expect. Lean burn is for scooters...

So yes, you need to move air, but only cos it's got bits of petrol in it.


>>Power is derived from the rate you burn petrol,
>
> No it is not, that totally ignores engine efficiency.

So?


>>the amount of power made
>>by an engine may be measured by the torque it produces at an angular velocity,
>>if you want,
> YES, YES, YES (Did you ever see 'When Harry met Sally'?)
>
>>but you can measure it in other ways.
>>
> Go on then you know you want to......................... :-)

Ok then. Accelerate the bike until it hits the rev limiter, measure its
speed every Nth of a second. e.g. 0s, 0.1s, 0.2s, and so on.

Measure the mass of bike and rider, and measure its air resistance coef.

Increase in kinetic energy can be calculated directly from it's mass and the
difference in speed, and energy loss due to friction can be calculated from
integrating the drag function over the run.

Add one to the other, and differentiate wrt time and you have the actual
power output curve of the bike at the rear wheel, in real road conditions,
rather than a dyno's 'corrected' figure. You could even do it in different
gears, if you want.

Actually, you could do the same on a dyno-like thing - measure the rate
of increase in energy of a drum as you accelerate it with the rear wheel,
which would cut out the drag figure, tho it would also lose any ram-air
effect.

--
ZX7RR.

[Gunga Dan]

"Verdigris" <verdigris@deadspam.com> wrote

> On Sun, 16 Jan 2005 01:13:12 +0000, Preston Kemp wrote:
>
>> Verdigris wrote:
>>
>>> On Sat, 15 Jan 2005 23:41:45 +0000, Gunga Dan wrote:
>>>
>>> > Champ <news@champ.org.uk> wrote
>>> <SNIP>
>>>
>>> >> Most people equate "torque" to "low/mid-range acceleration", and
>>> >> thus >> say things like "twins have more torque than fours".
>>> >> Well:
>>> >>
>>> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm Suzuki GSX-R
>>> >> 1000: >> 83.3 ft.lbs of torque at 8400 rpm
>>> >
>>> > Yes but how about comparing the torque outputs of two bikes with
>>> > similar peak power outputs. I think it's more to do with twins
>>> > having more torque relative to the amount of power they produce
>>> > which makes people describe them as 'torquey'.
>>>
>>> No it isn't. You can't have "more torque relative to the amount of
>>> power they produce", because one is directly proportional to the
>>> other.
>>
>> Have to disagree with that. If you've got two bikes both making 120bhp
>> peak, one at 12000 rpm & one at 8000 rpm, the latter must be making
>> more torque relative to it's power output.
>
> That's just fiddling with the numbers. Torque and power *are* directly
> related to one another.

It's not fiddling with figures at all. Take a Harley that makes say 60lbft
of torque it might only make 60BHP, so relative to it's power output, it's
making lots of torque[1] and will to the rider feel 'torquey'. Granted, it's
because that's all there is.

[1] Or if you prefer bugger-all power relative to its maximum torque.

[Ace]

On Sat, 15 Jan 2005 16:23:38 +0000, Champ <news@champ.org.uk> wrote:

>On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
>wrote:
>
>>Can I just say at this moment that I have absolutely no ****in clue what
>>the difference is between torque and HP apart from torque occurs
>>lower in the revs and bikes feel good when revving high so I likes
>>HP more, and the higher the numbers the better...
>
>Everything you know is wrong.
>
>Well, the bit above is.
>
>Most people equate "torque" to "low/mid-range acceleration", and thus
>say things like "twins have more torque than fours". Well:

Indeed, and as such is the source of the confusion to which you
alluded earlier. In general, singles and twins, especially in a low
state of tune, develop their max power ( and torque) much lower in the
rev range, so feel more tractable at such engine speeds, giving the
illusion that they're more 'torquey' than their multi-cylinder
cousins. It also often gives them a wider spread of torque, which
again helps maintain that illusion.

>Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm

Well yes, and as I've said before you could pretty much ride the
gixxer with just a single gear and still have shed-loads of
acceleration available all the way up, as it were. But that's a
relatively recently obtained phenomenon, TBH. Ten years ago the peak
torque would still have been higher but the curve much more peaky.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Sun, 16 Jan 2005 00:18:47 GMT, "Preston Kemp"
<dontwantany@nowhere.invalid> wrote:

>Champ wrote:

>> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
>> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
>
>Those figures only show peak torque though. I bet it's a different
>story at say 3000 rpm, where the TL probably does have more torque than
>the gixer.

Actually, although I haven't studied the curves, I suspect you may be
wrong. The gixxer motor is quite amazing in that respect.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Sat, 15 Jan 2005 22:44:54 -0000, Simian
<Simian@in_valid.semi-evolved.org> wrote:

>Ace was saying that torque was important, not power,

Oi! That's twisting my words. my point was, and is, that it's torque,
not power, that forms as an absolute measure of the amount of
acceleration available. As previously quoted, a=T/I
(acceleration=Torque/Inertia).

>all I've said is
>is that power and it's spread and gearing is the actual important thing.

The rev range over which said torque is available is very important to
_maintain_ that acceleration, of course, and as previously discussed,
there is an inherent relationship between Torque and Power, based
around revs.

But lets's be clear, if you have engine A that produces 50bhp at
10500rpm and engine B that produces 50bhp and 5250rpm, engine B, which
is making twice as much torque, will be able to accelerate a body
twice as fast (at that engine speed) as Engine A.

>The width of the power band doesn't care about torque. You can have 100bhp
>across a 1000rpm power band centred on 5000, or 50,000rpm, with a ten-fold
>difference in torque (at the crank) and the ability to accellerate is the same,

That's a fundamental error, I'm afraid. As shown above, acceleration
is directly proportional to torque and doesn't care about revs or
power at all.


--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Preston Kemp]

Ace wrote:

> On Sun, 16 Jan 2005 00:18:47 GMT, "Preston Kemp"
> <dontwantany@nowhere.invalid> wrote:
>
> > Champ wrote:
>
> >> Suzuki TL 1000: 72.6 ft-lbs of torque at 8250 rpm
> >> Suzuki GSX-R 1000: 83.3 ft.lbs of torque at 8400 rpm
> >
> > Those figures only show peak torque though. I bet it's a different
> > story at say 3000 rpm, where the TL probably does have more torque
> > than the gixer.
>
> Actually, although I haven't studied the curves, I suspect you may be
> wrong. The gixxer motor is quite amazing in that respect.

A quick Google for dyno charts seems to show the TL does beat it, but
only by a few ft-lbs - not that it really means anything unless the
runs are done on the same dyno in similar conditions. It's certainly
closer than I thought it would be though.

I'll have to go searching for MV Tamburini charts now to see how that
compares with its variable-length inlets.

--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Mick Whittingham]

In article <10ulnmape2tm1d0@news.supernews.com>, Simian
<Simian@in_valid.semi-evolved.org> writes
>Mick Whittingham wrote:
>>>


>
>>>Power is derived from the rate you burn petrol,
>>
>> No it is not, that totally ignores engine efficiency.
>
>So?
>
>
>>>the amount of power made
>>>by an engine may be measured by the torque it produces at an angular
>>>velocity,
>>>if you want,
>> YES, YES, YES (Did you ever see 'When Harry met Sally'?)
>>
>>>but you can measure it in other ways.
>>>
>> Go on then you know you want to......................... :-)
>
>Ok then. Accelerate the bike until it hits the rev limiter, measure its
>speed every Nth of a second. e.g. 0s, 0.1s, 0.2s, and so on.
>
>Measure the mass of bike and rider, and measure its air resistance coef.
>
>Increase in kinetic energy can be calculated directly from it's mass and the
>difference in speed, and energy loss due to friction can be calculated from
>integrating the drag function over the run.
>
>Add one to the other, and differentiate wrt time and you have the actual
>power output curve of the bike at the rear wheel, in real road conditions,
>rather than a dyno's 'corrected' figure. You could even do it in different
>gears, if you want.
>
>Actually, you could do the same on a dyno-like thing - measure the rate
>of increase in energy of a drum as you accelerate it with the rear wheel,
>which would cut out the drag figure, tho it would also lose any ram-air
>effect.
>

There! I knew you wanted to!

Interesting point (maybe):

When I was working on a competition saloon car in the late 60's early
70's with the genius in the subject who was preparing it:

A Ford Anglia shape.
Space frame front of the fire wall.
Wish bone suspension with anti dive.
Fiat twin cam engine extensively moded.
5 speed box with selected ratios
etc.

After looking at the torque and power curves off of the dyno he decided
to reduce the 45 DCOE Webers for 40s.
Along with other mods it dropped the max HP a tad but nearly double the
width of the torque curve.
The effect on the track times was a significant reduction.
All to do with matching the engine to the gear box and vice verca plus
what you want to do with it.

--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[TimP]

Ace wrote:

> Oi! That's twisting my words. my point was, and is, that it's torque,
> not power, that forms as an absolute measure of the amount of
> acceleration available. As previously quoted, a=T/I
> (acceleration=Torque/Inertia).

Yebbut... Torque can be changed at a given engine speed by altering the
gearing, whereas a less torquey engine can be made more powerful by
increasing the rev range.

>
> >all I've said is
> >is that power and it's spread and gearing is the actual important
thing.
>
> The rev range over which said torque is available is very important
to
> _maintain_ that acceleration, of course, and as previously discussed,
> there is an inherent relationship between Torque and Power, based
> around revs.

Power is an integral of torque.

>
> But lets's be clear, if you have engine A that produces 50bhp at
> 10500rpm and engine B that produces 50bhp and 5250rpm, engine B,
which
> is making twice as much torque, will be able to accelerate a body
> twice as fast (at that engine speed) as Engine A.

Hmm - but an engine turning at 10,500rpm can be geared twice as highly
as one that's twice as torquey but rotating at half the speed, so you'd
get the same acceleration if geared correctly.

>
> >The width of the power band doesn't care about torque. You can have
100bhp
> >across a 1000rpm power band centred on 5000, or 50,000rpm, with a
ten-fold
> >difference in torque (at the crank) and the ability to accellerate
is the same,
>
> That's a fundamental error, I'm afraid. As shown above, acceleration
> is directly proportional to torque and doesn't care about revs or
> power at all.


Your equation is fine but ignores the way torque is altered by gearing.
TimP

[Ace]

On 17 Jan 2005 04:39:19 -0800, "TimP" <tjpulham@hotmail.com> wrote:

>
>Ace wrote:
>
>> Oi! That's twisting my words. my point was, and is, that it's torque,
>> not power, that forms as an absolute measure of the amount of
>> acceleration available. As previously quoted, a=T/I
>> (acceleration=Torque/Inertia).
>
>Yebbut... Torque can be changed at a given engine speed by altering the
>gearing,

You what? I think you're a little confused. (Max. available) torque at
any given engine speed is constant. (Gearing can be used to better
match this engine speed to the road speed(s) at which it's wanted.
Maybe that's what's causing the confusion here?)

>Power is an integral of torque.

You _are_ confused, aren't you? Power=torque*revs. That's not an
integral.

<big snip>

>Your equation is fine but ignores the way torque is altered by gearing.

It's not. At all. Not even a little bit.

HTH
--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[TimP]

Ace wrote:

> You what? I think you're a little confused. (Max. available) torque
at
> any given engine speed is constant. (Gearing can be used to better
> match this engine speed to the road speed(s) at which it's wanted.
> Maybe that's what's causing the confusion here?)

For instance, an electric screwdriver uses its gearbox to increase the
available torque from feeble -> less feeble. You could stop the motor
with two fingers if it didn't go through the gearbox. The power output
of the motor is unchanged.

>
> >Power is an integral of torque.
>
> You _are_ confused, aren't you? Power=torque*revs. That's not an
> integral.

Conceded (oops).

> >Your equation is fine but ignores the way torque is altered by
gearing.
>
> It's not. At all. Not even a little bit.

So how does my electric screwdriver produce enough torque to drive in
screws from its pathetic (but relatively fast-spinning) motor? Does
your bike accelerate at the same rate regardless of which gear it's in?
What's the point of a massive sprocket at the back wheel and a small
one at the gearbox if it isn't to increase the torque available at the
back wheel?


TimP

[Mick Whittingham]

In article <1105969703.804858.267500@z14g2000cwz.googlegroups. com>, TimP
<tjpulham@hotmail.com> writes
>
>Ace wrote:
>
>
>So how does my electric screwdriver produce enough torque to drive in
>screws from its pathetic (but relatively fast-spinning) motor? Does
>your bike accelerate at the same rate regardless of which gear it's in?
>What's the point of a massive sprocket at the back wheel and a small
>one at the gearbox if it isn't to increase the torque available at the
>back wheel?
>
>


What you need is a steam powered bike.
Maximum torque from zero rpm.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[darsy]

Ace wrote:
> On 17 Jan 2005 04:39:19 -0800, "TimP" <tjpulham@hotmail.com> wrote:
>
> >Yebbut... Torque can be changed at a given engine speed by altering
the
> >gearing,

> You _are_ confused, aren't you? Power=torque*revs. That's not an
> integral.
>
> >Your equation is fine but ignores the way torque is altered by
gearing.
>
> It's not. At all. Not even a little bit.

but if torque /isn't/ altered by gearing, then your equation above is
not true...

--
d.

[Ace]

On 17 Jan 2005 05:48:23 -0800, "TimP" <tjpulham@hotmail.com> wrote:

>
>Ace wrote:
>
>> You what? I think you're a little confused. (Max. available) torque
>at
>> any given engine speed is constant. (Gearing can be used to better
>> match this engine speed to the road speed(s) at which it's wanted.
>> Maybe that's what's causing the confusion here?)
>
>For instance, an electric screwdriver uses its gearbox to increase the
>available torque from feeble -> less feeble. You could stop the motor
>with two fingers if it didn't go through the gearbox.

How do you know? Did you remove all the gearing and try it?

>The power output of the motor is unchanged.

As is the torque.

<snip>

I CBA any more. Go back and read the previous postings.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On 17 Jan 2005 06:02:21 -0800, "darsy" <darsyx@gmail.com> wrote:

>
>Ace wrote:
>> On 17 Jan 2005 04:39:19 -0800, "TimP" <tjpulham@hotmail.com> wrote:
>>
>> >Yebbut... Torque can be changed at a given engine speed by altering
>the
>> >gearing,
>
>> You _are_ confused, aren't you? Power=torque*revs. That's not an
>> integral.
>>
>> >Your equation is fine but ignores the way torque is altered by
>gearing.
>>
>> It's not. At all. Not even a little bit.
>
>but if torque /isn't/ altered by gearing, then your equation above is
>not true...

Eh? (engine)Power=(engine)Torque*(engine)revs. How would gearing
affect this?

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[darsy]

Ace wrote:
> On 17 Jan 2005 06:02:21 -0800, "darsy" <darsyx@gmail.com> wrote:
>
> >but if torque /isn't/ altered by gearing, then your equation above
is
> >not true...
>
> Eh? (engine)Power=(engine)Torque*(engine)revs. How would gearing
> affect this?

OK, let's frame the question differently. Are you saying that torque at
the rear axle is not affected by a change of gearing for a given power?


Work back through the drive, to the front sprocket. Then through the
various gears. You're saying that torque is not affected no matter what
gearing has been selected?

At what point does your power=torque*revs equation miraculously spring
into existance - at the crank only?

--
d.

[mups]

darsy darsyx@gmail.com says...
>
> At what point does your power=torque*revs equation miraculously spring
> into existance - at the crank only?

Power=torque*revs no matter where you measure it. But if you change the
gearing to increase the torque then then revs and hence the power drops.

Methinks Ace is arguing about crank speeds only and everybody else rear
wheel torque/power, which is of course the useful one.

--
Chris
CBR1000FL The Honda Fatblade
Yam RS200 Transcontinental Tourer

[Ace]

On 17 Jan 2005 06:32:12 -0800, "darsy" <darsyx@gmail.com> wrote:

>
>Ace wrote:
>> On 17 Jan 2005 06:02:21 -0800, "darsy" <darsyx@gmail.com> wrote:
>>
>> >but if torque /isn't/ altered by gearing, then your equation above
>is
>> >not true...
>>
>> Eh? (engine)Power=(engine)Torque*(engine)revs. How would gearing
>> affect this?
>
>OK, let's frame the question differently. Are you saying that torque at
>the rear axle is not affected by a change of gearing for a given power?

No. If you change the gearing at an given road speed, then you're also
changing the engine speed and hence both the torque and the power
being delivered.

But if you imagine being at a given engine speed both the power and
torque available would be constant regardless of what gear you were
in. So when you're going up through the gears on your bike, the
accelerating force produced at any given rpm is the same in each gear.

>Work back through the drive, to the front sprocket. Then through the
>various gears. You're saying that torque is not affected no matter what
>gearing has been selected?

Forgetting any loss through the chain, etc. then yes - the torque and
power at the rear wheel are the same as that at the crank, regardless
of gearing.

>At what point does your power=torque*revs equation miraculously spring
>into existance - at the crank only?

It's inherent, but of course it's talking about engine revs, not
sprocket or wheel revs. And it's not my equation, it's a definition.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[darsy]

Ace wrote:
> On 17 Jan 2005 06:32:12 -0800, "darsy" <darsyx@gmail.com> wrote:
>
> >OK, let's frame the question differently. Are you saying that torque
at
> >the rear axle is not affected by a change of gearing for a given
power?
>
> No. If you change the gearing at an given road speed, then you're
also
> changing the engine speed and hence both the torque and the power
> being delivered.

OK, I'm beginning to suspect you're being deliberately and willfully
awkward now.

Would you disagree that /for a given engine speed/ changing the gearing
changes the torque /at the rear wheel/?

Another analogous comparison for you - why is it easier for someone to
lift a heavy object using a rope and multiple-pulleyed block-and-tackle
than it is for that same person to raise the same object using just a
rope and one pulley?

Gearing multiplies the force required. Torque is rotational force.
Gearing multiplies torque.

>From the dictionary definition of torque:

"a measure of the effectiveness of such a force that consists of the
product of the force and the perpendicular distance from the line of
action of the force to the axis of rotation"
gearing changes torque.

QE-****ing-D.

--
d.

[Champ]

On Mon, 17 Jan 2005 15:59:16 +0100, Ace <b.rogers@virgin.net> wrote:

>But if you imagine being at a given engine speed both the power and
>torque available would be constant regardless of what gear you were
>in. So when you're going up through the gears on your bike, the
>accelerating force produced at any given rpm is the same in each gear.

My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
5000rpm. So, you seem to be stating the obvious - that at 5k the
torque and power *at the crank* is the same whatever the transmission
is doing. But that doesn't seem to advance the argument anywhere.

>Forgetting any loss through the chain, etc. then yes - the torque and
>power at the rear wheel are the same as that at the crank, regardless
>of gearing.

oh, you're not stating the obvious.

So, why does my bike accelrate harder in first?


--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[mups]

mups chrisl@NOTREALADDR.COM says...
> darsy darsyx@gmail.com says...
> >
> > At what point does your power=torque*revs equation miraculously spring
> > into existance - at the crank only?
>
> Power=torque*revs no matter where you measure it. But if you change the
> gearing to increase the torque then then revs and hence the power drops.
>
> Methinks Ace is arguing about crank speeds only and everybody else rear
> wheel torque/power, which is of course the useful one.

<bad form and all that...>

Having thought about it. The power at the rear wheel stays constant
irrespective of gearing but the torque changes. Assuming a constant
engine RPM.

--
Chris
CBR1000FL The Honda Fatblade
Yam RS200 Transcontinental Tourer

[TimP]

Ace wrote:

> How do you know? Did you remove all the gearing and try it?

No, no, I haven't; it was an illustration that the driving power - the
torque - can vary greatly by changing the gearing. A quick google gives
the gearing of a screwdriver at 68:1. Yep, you guessed it - 68 times
the torque, 1/68th the rpm.

> >The power output of the motor is unchanged.
>
> As is the torque.


The power output at the back wheel is unchanged. The torque - and thus
the acceleration - at the back wheel does vary with gearing. I don't
understand what's weird about this - you seem to be arguing that the
torque produced at the crank doesn't change when you add a gearbox onto
it, which is a truism. However, the output from the gearbox _must_ have
a different torque if it is rotating at a different speed, because the
power output has to remain the same (excluding frictional loss).


> I CBA any more. Go back and read the previous postings.

Suit yourself. It would seem clear, though, that your statement
"...acceleration is directly proportional to torque and doesn't care
about revs or power at all" isn't true. Acceleration is proportional to
torque *at the back wheel*, and (as you corrected me) torque =
power/revs (or rather is proportional to); so you _must_ be able to
increase the torque by reducing the revs.


TimP

[darsy]

mups wrote:

> Having thought about it. The power at the rear wheel stays constant
> irrespective of gearing but the torque changes. Assuming a constant
> engine RPM.

which is what I said in my first post in this sub-thread, and
re-iterated in my subsequent replies to Ace.
I think he's trolling.

--
d.

[Toby Augh-Nottoby]

"Mick Whittingham" <Mick@whittinghamsite.fsnet.co.uk> wrote in message
news:HfKsXWSJS86BFwvM@whittinghamsite.fsnet.co.uk. ..
> In article <1105969703.804858.267500@z14g2000cwz.googlegroups. com>, TimP
> <tjpulham@hotmail.com> writes
>>
>>Ace wrote:
>>
>>So how does my electric screwdriver produce enough torque to drive in
>>screws from its pathetic (but relatively fast-spinning) motor? Does
>>your bike accelerate at the same rate regardless of which gear it's in?
>>What's the point of a massive sprocket at the back wheel and a small
>>one at the gearbox if it isn't to increase the torque available at the
>>back wheel?
>
> What you need is a steam powered bike.
> Maximum torque from zero rpm.

Perhaps there's a gap in the market for a steam-powered screwdriver!

[mups]

darsy darsyx@gmail.com says...
>
> mups wrote:
>
> > Having thought about it. The power at the rear wheel stays constant
> > irrespective of gearing but the torque changes. Assuming a constant
> > engine RPM.
>
> which is what I said in my first post in this sub-thread, and
> re-iterated in my subsequent replies to Ace.
> I think he's trolling.

Having gone back and read the whole sub-thread I think you may be right.
But OTOH he is blonde...

--
Chris
CBR1000FL The Honda Fatblade
Yam RS200 Transcontinental Tourer

[Ace]

On 17 Jan 2005 07:11:03 -0800, "darsy" <darsyx@gmail.com> wrote:

>OK, I'm beginning to suspect you're being deliberately and willfully
>awkward now.

Not at all. I'm just not sure what you're trying to say.

>Would you disagree that /for a given engine speed/ changing the gearing
>changes the torque /at the rear wheel/?

I would. It doesn't.

>Another analogous comparison for you - why is it easier for someone to
>lift a heavy object using a rope and multiple-pulleyed block-and-tackle
>than it is for that same person to raise the same object using just a
>rope and one pulley?

Mechanical advantage. The same amount of energy is being used in each
case. What's it got to do with torque?

>Gearing multiplies the force required.

Eh? That's news to me. F=Ma applies regardless of gearing, you know.
The force required to accelerate a given mass is constant.

>Torque is rotational force.
>Gearing multiplies torque.

Where do you get this from?

>>From the dictionary definition of torque:
>
>"a measure of the effectiveness of such a force that consists of the
>product of the force and the perpendicular distance from the line of
>action of the force to the axis of rotation"

Yees, I'm aware of that. And your point is?

>gearing changes torque.

How, exactly, do you reach that conclusion? Clearly it's something you
feel is self-evident, but I'd really appreciate it if you could
explain.

And no, I'm not trolling, just struggling to see what you're trying to
get at.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 17 Jan 2005 15:59:16 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>But if you imagine being at a given engine speed both the power and
>>torque available would be constant regardless of what gear you were
>>in. So when you're going up through the gears on your bike, the
>>accelerating force produced at any given rpm is the same in each gear.
>
>My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
>5000rpm.

Only because of drag and frictional resistance.

>So, you seem to be stating the obvious - that at 5k the
>torque and power *at the crank* is the same whatever the transmission
>is doing. But that doesn't seem to advance the argument anywhere.

Oh, well what other argument is there?

>>Forgetting any loss through the chain, etc. then yes - the torque and
>>power at the rear wheel are the same as that at the crank, regardless
>>of gearing.
>
>oh, you're not stating the obvious.
>
>So, why does my bike accelrate harder in first?

"because of drag and frictional resistance."

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[darsy]

Ace wrote:
> On 17 Jan 2005 07:11:03 -0800, "darsy" <darsyx@gmail.com> wrote:

> >Would you disagree that /for a given engine speed/ changing the
gearing
> >changes the torque /at the rear wheel/?
>
> I would. It doesn't.

ah, well, there's little point continuing with the discussion. I, and
apparently mups and Champ thing my statement above is true, you
apparently don't.
"Prove it to me and I still won't believe it".

--
d.

[Champ]

On Mon, 17 Jan 2005 16:55:26 +0100, Ace <b.rogers@virgin.net> wrote:

>On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
>
>>On Mon, 17 Jan 2005 15:59:16 +0100, Ace <b.rogers@virgin.net> wrote:
>>
>>>But if you imagine being at a given engine speed both the power and
>>>torque available would be constant regardless of what gear you were
>>>in. So when you're going up through the gears on your bike, the
>>>accelerating force produced at any given rpm is the same in each gear.
>>
>>My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
>>5000rpm.
>
>Only because of drag and frictional resistance.

You're kidding me? You think the only reason that a bike accerates
slower in top gear is because of the increased wind resistance due to
the higher actual speed?

I'm really looking forward to your apology when it comes :-)
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[darsy]

Champ wrote:
> On Mon, 17 Jan 2005 16:55:26 +0100, Ace <b.rogers@virgin.net> wrote:
>
> >On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
> >
> >>My bike accelrates harder in 1st gear at 5000rpm than in 6th gear
at
> >>5000rpm.
> >
> >Only because of drag and frictional resistance.
>
> You're kidding me? You think the only reason that a bike accerates
> slower in top gear is because of the increased wind resistance due to
> the higher actual speed?
>
> I'm really looking forward to your apology when it comes :-)

for someone who usually comes across as reasonably intelligent and
knowledgeble about a wide range of matters, he's really dropped a
bollock on this one, IYAM.

--
d.

[flash]

"darsy" <darsyx@gmail.com> wrote in message
news:1105978491.631493.12030@c13g2000cwb.googlegro ups.com...
>
> Champ wrote:
> > On Mon, 17 Jan 2005 16:55:26 +0100, Ace <b.rogers@virgin.net> wrote:
> >
> > >On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
> > >
> > >>My bike accelrates harder in 1st gear at 5000rpm than in 6th gear
> at
> > >>5000rpm.
> > >
> > >Only because of drag and frictional resistance.
> >
> > You're kidding me? You think the only reason that a bike accerates
> > slower in top gear is because of the increased wind resistance due to
> > the higher actual speed?
> >
> > I'm really looking forward to your apology when it comes :-)
>
> for someone who usually comes across as reasonably intelligent and
> knowledgeble about a wide range of matters, he's really dropped a
> bollock on this one, IYAM.
>
"Ace high, sense low"

[darsy]

Ace wrote:
> On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
>
> >So, why does my bike accelrate harder in first?
>
> "because of drag and frictional resistance."

OK - why doesn't Champ's bike wheelie as easy in 5th as it does in 1st
for a given engine speed?

After all, you've stated that the torque - the ability of a force to
cause a rotation - isn't changed by gearing, so the ability of the
engine torque to rotate the front of the bike off the ground, against
the - constant - force of gravity is - according to you - identical in
each gear...


--
d.

[Ace]

On Mon, 17 Jan 2005 16:10:20 +0000, Champ <neal@champ.org.uk> wrote:

>On Mon, 17 Jan 2005 16:55:26 +0100, Ace <b.rogers@virgin.net> wrote:
>
>>On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:

>>>My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
>>>5000rpm.
>>
>>Only because of drag and frictional resistance.
>
>You're kidding me? You think the only reason that a bike accerates
>slower in top gear is because of the increased wind resistance due to
>the higher actual speed?

<digs deeper>

Actually, yes. It's all quite simple physics. Force = mass *
acceleration. Your engine's developing a set amount of force at a
given engine speed/throttle setting, right? It's using the chain and
rear wheel to convert that rotational force (Torque) to a forward
force. With me so far?

OK, so the engine Torque is constant, the mass is constant, therefore
the acceleration is constant.

Fighting against this forward acceleration is (mainly) wind
resistance. What's the normally quoted formula? Double the speed,
square the force required? Something like that, anyway.

You and darsy seem to be arguing that changing the gearing somehow
magnifies the amount of force available - I want to know where you
think the extra force comes from.

>I'm really looking forward to your apology when it comes :-)

As long as you're prepared to give what you hope to take.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[WavyDavy]

"mups" <chrisl@NOTREALADDR.COM> wrote in message
news:MPG.1c55e9b0ef19a97098986d@news.newsreader.co m...
> mups chrisl@NOTREALADDR.COM says...
>> darsy darsyx@gmail.com says...
>> >
>> > At what point does your power=torque*revs equation miraculously spring
>> > into existance - at the crank only?
>>
>> Power=torque*revs no matter where you measure it. But if you change the
>> gearing to increase the torque then then revs and hence the power drops.
>>
>> Methinks Ace is arguing about crank speeds only and everybody else rear
>> wheel torque/power, which is of course the useful one.
>
> <bad form and all that...>
>
> Having thought about it. The power at the rear wheel stays constant
> irrespective of gearing but the torque changes. Assuming a constant
> engine RPM.

Or, possibly, what you mean is that power (and, therefore torque) stay they
same, but the amount of *thrust* applied at the rear wheel chnges depending
on gearing....

ISTR John Robinson writing on the subject in PB a year or two before his
death and for a few years PB used to print Power, Torque and Thrust curves
to show why a bike with significantly less power/torque than another could
still feel 'more powerful' through clever use of gearing ratios...

Dave

[Ace]

On 17 Jan 2005 08:18:12 -0800, "darsy" <darsyx@gmail.com> wrote:

>
>Ace wrote:
>> On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
>>
>> >So, why does my bike accelrate harder in first?
>>
>> "because of drag and frictional resistance."
>
>OK - why doesn't Champ's bike wheelie as easy in 5th as it does in 1st
>for a given engine speed?

Because he's fighting much greater wind resistance, which is acting as
a negative accelration, therefore needing positive acceleration to
counter it. If this were not the case we wouldn;t need to hold the
throttle open once we'd reahced a given speed. As a result, the
_extra_ accelration available is much lower than it would be at the
same engine speed in first gear.

>After all, you've stated that the torque - the ability of a force to
>cause a rotation - isn't changed by gearing, so the ability of the
>engine torque to rotate the front of the bike off the ground, against
>the - constant - force of gravity is - according to you - identical in
>each gear...

Yes, in a friction-free vacuum.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Mon, 17 Jan 2005 16:24:54 +0000 (UTC), "WavyDavy"
<dnk.haynes@btinternet.com> wrote:

>
>"mups" <chrisl@NOTREALADDR.COM> wrote in message
>news:MPG.1c55e9b0ef19a97098986d@news.newsreader.co m...
>> mups chrisl@NOTREALADDR.COM says...
>>> darsy darsyx@gmail.com says...
>>> >
>>> > At what point does your power=torque*revs equation miraculously spring
>>> > into existance - at the crank only?
>>>
>>> Power=torque*revs no matter where you measure it. But if you change the
>>> gearing to increase the torque then then revs and hence the power drops.
>>>
>>> Methinks Ace is arguing about crank speeds only and everybody else rear
>>> wheel torque/power, which is of course the useful one.
>>
>> <bad form and all that...>
>>
>> Having thought about it. The power at the rear wheel stays constant
>> irrespective of gearing but the torque changes. Assuming a constant
>> engine RPM.
>
>Or, possibly, what you mean is that power (and, therefore torque) stay they
>same, but the amount of *thrust* applied at the rear wheel chnges depending
>on gearing....

Finally, someone with a clue. And the words to express it, which I've
been failing with.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[TimP]

Ace wrote:

> You and darsy seem to be arguing that changing the gearing somehow
> magnifies the amount of force available - I want to know where you
> think the extra force comes from.

Works in exactly the same way as a lever. You do understand you can
increase a force by using a lever, don't you?

The work done remains the same. Force is increased, and the distance
travelled is decreased.

So by changing the gearing, the bike travels more slowly at a given
engine speed, but accelerates more rapidly as more force (read: torque)
is available at the back wheel.

TimP

[mups]

Ace b.rogers@virgin.net says...
> >
> >You're kidding me? You think the only reason that a bike accerates
> >slower in top gear is because of the increased wind resistance due to
> >the higher actual speed?
>
> <digs deeper>

I'm fairly sure you're trolling here, but...

> Actually, yes. It's all quite simple physics. Force = mass *
> acceleration.

And E=MC^2 so what.

> Your engine's developing a set amount of force at a
> given engine speed/throttle setting, right? It's using the chain and
> rear wheel to convert that rotational force (Torque) to a forward
> force. With me so far?

You've missed the gearbox out.

> OK, so the engine Torque is constant, the mass is constant, therefore
> the acceleration is constant.

Engine torque is constant, but rear wheel torque changes depending on
which gear the gearbox is in.

> Fighting against this forward acceleration is (mainly) wind
> resistance. What's the normally quoted formula? Double the speed,
> square the force required? Something like that, anyway.

Wind resistance has nothing to do with it. My bike accelerates faster
from 20MPH in 1st than it does in 6th.

--
Chris
CBR1000FL The Honda Fatblade
Yam RS200 Transcontinental Tourer

[darsy]

TimP wrote:
> Ace wrote:
>
> > You and darsy seem to be arguing that changing the gearing somehow
> > magnifies the amount of force available - I want to know where you
> > think the extra force comes from.
>
> Works in exactly the same way as a lever. You do understand you can
> increase a force by using a lever, don't you?

I was going to use the lever analogy, but went with block-and-tackle
because it involved rotation. But you're right - a gearbox is analogous
to a selectable set of levers of differing lengths.

I think Ace is confusing force and work. Of course I wouldn't claim
that gearing affects the amount of work done by an engine at a given
engine-speed.


--
d.

[TimP]

darsy wrote:
> I think Ace is confusing force and work.


Absolutely.

TimP

[Ace]

On 17 Jan 2005 08:34:05 -0800, "TimP" <tjpulham@hotmail.com> wrote:

>
>Ace wrote:
>
>> You and darsy seem to be arguing that changing the gearing somehow
>> magnifies the amount of force available - I want to know where you
>> think the extra force comes from.
>
>Works in exactly the same way as a lever. You do understand you can
>increase a force by using a lever, don't you?

Yes, but the Torque remains the same. Imagine a lever three metres
long with the pivot at the 2-metre mark. Now apply a force of 1N to
the long end. The moment, or torque, is therefore 2Nm. The short end
will have a force of 2N acting on it, but it's only 1m away from the
pivot. so the moment, or torque, at that end is 2Nm. Exactly the same,
do you see?

So my use of the word 'Force' was wrong, I grant you. But the original
point was about Torque, which will remain the same however long your
lever is.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On 17 Jan 2005 08:39:23 -0800, "darsy" <darsyx@gmail.com> wrote:

>
>TimP wrote:
>> Ace wrote:
>>
>> > You and darsy seem to be arguing that changing the gearing somehow
>> > magnifies the amount of force available - I want to know where you
>> > think the extra force comes from.
>>
>> Works in exactly the same way as a lever. You do understand you can
>> increase a force by using a lever, don't you?
>
>I was going to use the lever analogy, but went with block-and-tackle
>because it involved rotation.

I wish you'd used levers - it would have been simpler.

>But you're right - a gearbox is analogous
>to a selectable set of levers of differing lengths.
>
>I think Ace is confusing force and work.

Yes, I apologise for that. But let's get back to torque...

>Of course I wouldn't claim
>that gearing affects the amount of work done by an engine at a given
>engine-speed.

Good-oh. Although Tim seems to be doing just that.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[darsy]

Ace wrote:
> On 17 Jan 2005 08:18:12 -0800, "darsy" <darsyx@gmail.com> wrote:
>
> >OK - why doesn't Champ's bike wheelie as easy in 5th as it does in
1st
> >for a given engine speed?
>
> Because he's fighting much greater wind resistance, which is acting
as
> a negative accelration, therefore needing positive acceleration to
> counter it.

<fx: shakes head sadly and walks away>

--
d.

[Champ]

On Mon, 17 Jan 2005 17:28:16 +0100, Ace <b.rogers@virgin.net> wrote:

>On 17 Jan 2005 08:18:12 -0800, "darsy" <darsyx@gmail.com> wrote:
>
>>
>>Ace wrote:
>>> On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
>>>
>>> >So, why does my bike accelrate harder in first?
>>>
>>> "because of drag and frictional resistance."
>>
>>OK - why doesn't Champ's bike wheelie as easy in 5th as it does in 1st
>>for a given engine speed?

Exactly the question I was going to ask.

>Because he's fighting much greater wind resistance, which is acting as
>a negative accelration, therefore needing positive acceleration to
>counter it. If this were not the case we wouldn;t need to hold the
>throttle open once we'd reahced a given speed. As a result, the
>_extra_ accelration available is much lower than it would be at the
>same engine speed in first gear.

This is so, so wrong!

While I can see that you believe that the wind resitance is affecting
the bikes ability to accelerate forwards (which of course, it does,
tho not nearly enough to account for the difference in gearing), it
surely can't have an affect on the bikes tendency to rotate around the
rear wheel spindle.
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[Preston Kemp]

Ace wrote:

> On 17 Jan 2005 08:18:12 -0800, "darsy" <darsyx@gmail.com> wrote:
>
> > OK - why doesn't Champ's bike wheelie as easy in 5th as it does in
> > 1st for a given engine speed?
>
> Because he's fighting much greater wind resistance, which is acting as
> a negative accelration, therefore needing positive acceleration to
> counter it.

If you do really believe that (which I very much doubt), try sticking a
2-teeth smaller front sprocket on your bike & nailing it in 1st gear
the way you usually do. I suggest you wear a back protector though ;-)


--
Preston.

http://www.muddystuff.co.uk
Off-road classifieds

'02 MV Senna '96 Tiger '79 Fantic 250
http://groups.yahoo.com/group/uk_tiger_rides

[Ace]

On Mon, 17 Jan 2005 17:11:56 +0000, Champ <neal@champ.org.uk> wrote:

>While I can see that you believe that the wind resitance is affecting
>the bikes ability to accelerate forwards (which of course, it does,
>tho not nearly enough to account for the difference in gearing), it
>surely can't have an affect on the bikes tendency to rotate around the
>rear wheel spindle.

But but but, if you're already using most of the available torque to
counter the decelleration presented by the wind, there's a very small
amount _extra_ available to cause further rotation.

I really can't understand what's so difficult about this.

OK, a thought experiment. If you had your bike on a rolling road [1]
that allowed the front end to lift, would it wheelie the same in top
as it does in first? If not, please explain to me why this should be
the case. Please.


[1] OK, so there are other factors, like rotational inertia, to deal
with, but they're relatively small fry by comparison.

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Mon, 17 Jan 2005 17:20:25 GMT, "Preston Kemp"
<dontwantany@nowhere.invalid> wrote:

>Ace wrote:
>
>> On 17 Jan 2005 08:18:12 -0800, "darsy" <darsyx@gmail.com> wrote:
>>
>> > OK - why doesn't Champ's bike wheelie as easy in 5th as it does in
>> > 1st for a given engine speed?
>>
>> Because he's fighting much greater wind resistance, which is acting as
>> a negative accelration, therefore needing positive acceleration to
>> counter it.
>
>If you do really believe that (which I very much doubt), try sticking a
>2-teeth smaller front sprocket on your bike & nailing it in 1st gear
>the way you usually do. I suggest you wear a back protector though ;-)

Good point. I'm convinced. All other bets are off.

<fx: sound of crunching baseball cap>
--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Ace]

On Mon, 17 Jan 2005 16:10:20 +0000, Champ <neal@champ.org.uk> wrote:

>I'm really looking forward to your apology when it comes :-)

Sorry, I was wrong.

<FX: dodge's Windy's ghost taking a swing at me.>

--
Ace (brucedotrogers a.t rochedotcom)
GSX-R1000K3
BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Ace <b.rogers@virgin.net> saying
something like:

<widgey screwdrivers>

>>The power output of the motor is unchanged.
>
>As is the torque.

Of course it's changed. The torque at the final output gear is directly
changed by the gearing factor.



--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "TimP" <tjpulham@hotmail.com>
saying something like:

> so you _must_ be able to
>increase the torque by reducing the revs.

Of course you do. There is a drop in available power, because of gearing
losses, but generally the gearing ratio directly affects the torque
available at the final output.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember mups <chrisl@NOTREALADDR.COM>
saying something like:

>Power=torque*revs no matter where you measure it. But if you change the
>gearing to increase the torque then then revs and hence the power drops.

The overall power drops only in response to geartrain losses. It's
nothing to do with the revs being high or low.

100bhp into a gearbox will give you 100bhp out, less the frictional
losses (can be anything between 2 - 10%, depending on design). Assuming
it's a reduction gearbox (as most are) the torque is multiplied by the
same ratio as the gearing.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[TimP]

Ace wrote:

> Yes, but the Torque remains the same. Imagine a lever three metres
> long with the pivot at the 2-metre mark. Now apply a force of 1N to
> the long end. The moment, or torque, is therefore 2Nm. The short end
> will have a force of 2N acting on it, but it's only 1m away from the
> pivot. so the moment, or torque, at that end is 2Nm. Exactly the
same,
> do you see?

All this shows is that for the same torque you can drive different
gears. As you state, the two levers you are moving with your 2Nm torque
now have different forces on them. If you use each of the levers
(gears) to drive a 2m lever (gear), the 1st one produces 2 Nm, and the
second one 4 Nm.


TimP

[Christopher Des Clayes]

On Mon, 17 Jan 2005 13:58:33 +0000, Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> wrote:

>In article <1105969703.804858.267500@z14g2000cwz.googlegroups. com>, TimP
><tjpulham@hotmail.com> writes
>>
>>Ace wrote:
>>
>>
>>So how does my electric screwdriver produce enough torque to drive in
>>screws from its pathetic (but relatively fast-spinning) motor? Does
>>your bike accelerate at the same rate regardless of which gear it's in?
>>What's the point of a massive sprocket at the back wheel and a small
>>one at the gearbox if it isn't to increase the torque available at the
>>back wheel?
>>
>>
>
>
>What you need is a steam powered bike.
>Maximum torque from zero rpm.

May I recommend the Spagthorpe?


--
Chris Des Clayes (Header addresses are munged)
Reply to chris@ffcc.powernet.co.uk, but remove one "f"
VN1500 Drifter (Gertrude) - Twice the fun at half the speed.
Barrel Bikers (Buckingham) MCC (www.barrelbikers.co.uk) UKMC#9

[Simon Atkinson]

Mick Whittingham wrote:

> In article <1105969703.804858.267500@z14g2000cwz.googlegroups. com>,
> TimP <tjpulham@hotmail.com> writes
> >
> > Ace wrote:
> >
> >
> > So how does my electric screwdriver produce enough torque to drive
> > in screws from its pathetic (but relatively fast-spinning) motor?
> > Does your bike accelerate at the same rate regardless of which gear
> > it's in? What's the point of a massive sprocket at the back wheel
> > and a small one at the gearbox if it isn't to increase the torque
> > available at the back wheel?
> >
> >
>
>
> What you need is a steam powered bike.
> Maximum torque from zero rpm.

Isn't it actually maximum torque *at* zero rpm. As long as the piston
and crank-pin are at the optimum position.

[Mick Whittingham]

In article <1105978692.562408.252270@z14g2000cwz.googlegroups. com>,
darsy <darsyx@gmail.com> writes
>
>Ace wrote:
>> On Mon, 17 Jan 2005 15:15:05 +0000, Champ <neal@champ.org.uk> wrote:
>>
>> >So, why does my bike accelrate harder in first?
>>
>> "because of drag and frictional resistance."
>
>OK - why doesn't Champ's bike wheelie as easy in 5th as it does in 1st
>for a given engine speed?
>
I haven't actually notice that Champ has any problems in wheelying in
any gear.

On the other hand the gearbox acts as a torque converter.
Increasing the RPM and reducing the torque.
Thus maintaining the power as constant, less frictional losses in the
transmission.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[TimP]

Ace wrote:

> Good point. I'm convinced. All other bets are off.

I'm confused, eh? Patronising cnut ;)
> <fx: sound of crunching baseball cap>

Good good


TimP

[mups]

Ace b.rogers@virgin.net says...
> On 17 Jan 2005 08:34:05 -0800, "TimP" <tjpulham@hotmail.com> wrote:
>
> >
> >Ace wrote:
> >
> >> You and darsy seem to be arguing that changing the gearing somehow
> >> magnifies the amount of force available - I want to know where you
> >> think the extra force comes from.
> >
> >Works in exactly the same way as a lever. You do understand you can
> >increase a force by using a lever, don't you?
>
> Yes, but the Torque remains the same. Imagine a lever three metres
> long with the pivot at the 2-metre mark. Now apply a force of 1N to
> the long end. The moment, or torque, is therefore 2Nm. The short end
> will have a force of 2N acting on it, but it's only 1m away from the
> pivot. so the moment, or torque, at that end is 2Nm. Exactly the same,
> do you see?

Bzzt, no the torque is doubled, the distance the short end moves is
immaterial to the 'turning force' generated. You're confusing torque
with work.

--
Chris (XChrislX@Xchurchstone.comX) Remove X's for address
CBR1000FL The Honda Fatblade
Yam RS200 Ring-a-Ding

[Mick Whittingham]

In article <xn0dxdd4pauwk000@news.individual.net>, Simon Atkinson
<me9@privacy.net> writes
>Mick Whittingham wrote:
>
>> In article <1105969703.804858.267500@z14g2000cwz.googlegroups. com>,
>> TimP <tjpulham@hotmail.com> writes
>> >
>> > Ace wrote:
>> >
>> >
>> > So how does my electric screwdriver produce enough torque to drive
>> > in screws from its pathetic (but relatively fast-spinning) motor?
>> > Does your bike accelerate at the same rate regardless of which gear
>> > it's in? What's the point of a massive sprocket at the back wheel
>> > and a small one at the gearbox if it isn't to increase the torque
>> > available at the back wheel?
>> >
>> >
>>
>>
>> What you need is a steam powered bike.
>> Maximum torque from zero rpm.
>
>Isn't it actually maximum torque *at* zero rpm. As long as the piston
>and crank-pin are at the optimum position.
But if they are in the right place, voila!

My car produces max torque 36% of max revs and stays at that level to
90% of max revs.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Champ]

On Mon, 17 Jan 2005 18:25:37 +0100, Ace <b.rogers@virgin.net> wrote:

>On Mon, 17 Jan 2005 16:10:20 +0000, Champ <neal@champ.org.uk> wrote:
>
>>I'm really looking forward to your apology when it comes :-)
>
>Sorry, I was wrong.

Hurrah! It was certainly a merry dance you led us all :-)

><FX: dodge's Windy's ghost taking a swing at me.>

Oh, I think even she'd have expected an apology for this one!


--
Champ

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> saying something like:

>On the other hand the gearbox acts as a torque converter.

Uhuh.

>Increasing the RPM and reducing the torque.

Aherm. Been at the Tanglefoot again?

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Steve Uzochukwu]

On Sun, 16 Jan 2005 05:01:26 -0000, "Richard Wood" <news2@ukrm.co.uk>
wildly wibbled thus:

>"Steve Uzochukwu" <randombloke@genie.co.uk> wrote in message news:41e9b236.56947543@News.Individual.NET...
>> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
>> wildly wibbled thus:
>>
>> >Can I just say at this moment that I have absolutely no ****in clue what
>> >the difference is between torque and HP apart from torque occurs
>> >lower in the revs and bikes feel good when revving high so I likes
>> >HP more, and the higher the numbers the better...
>>
>> Not the owner of a direct injection diesel then?
>
>I'm with JC on diesels...
>

but surely, you're nice bloke, and he's a [fill in randon selection of
abusive terms here], as well as being prejudiced and not current.

YMMV.




--
Steve Uzochukwu, Avian Amour and Windtech Quarx.
http://www.steveu.org/
The UKRM FAQ: http://www.ukrm.net/faq/index.html
************************************************** *************

[Verdigris]

On Mon, 17 Jan 2005 15:15:05 +0000, Champ wrote:

<SNIP>

> My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
> 5000rpm.

AT 5000rpm, your bike doesn't accelerate at all in any gear.

[Mick Whittingham]

In article <bgeou0hbcf29n7h7ff1hio9fbnatae0dq4@4ax.com>, Grimly
Curmudgeon <grimlycurmudgeon683@hotmail.com> writes
>It was somewhere around Barstow, on the edge of the desert, when the
>drugs began to take hold. I remember Mick Whittingham
><Mick@whittinghamsite.fsnet.co.uk> saying something like:
>
>>On the other hand the gearbox acts as a torque converter.
>
>Uhuh.

OK stepped torque converter.
>
>>Increasing the RPM and reducing the torque.
>
>Aherm. Been at the Tanglefoot again?
>
You with Ace on this one then?
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Champ]

On Mon, 17 Jan 2005 23:53:40 +0000, "Verdigris"
<verdigris@deadspam.com> wrote:

>On Mon, 17 Jan 2005 15:15:05 +0000, Champ wrote:
>
><SNIP>
>
>> My bike accelrates harder in 1st gear at 5000rpm than in 6th gear at
>> 5000rpm.
>
>AT 5000rpm, your bike doesn't accelerate at all in any gear.

"from"
--
Please add "imo" to above post.
Champ
GSX-R 1000, GPz 750 turbo, ZX7RR Endurance Racer x 2
GYASB#0 BotToS#2 BOTAFO(T|F)#35 WG*#1 DFV#8
Team UKRM Racing : www.team-ukrm.com

[Simon Atkinson]

Mick Whittingham wrote:

> In article <xn0dxdd4pauwk000@news.individual.net>, Simon Atkinson
> <me9@privacy.net> writes
>
> >> What you need is a steam powered bike.
> >> Maximum torque from zero rpm.
> >
> > Isn't it actually maximum torque at zero rpm. As long as the piston
> > and crank-pin are at the optimum position.
> But if they are in the right place, voila!
>
> My car produces max torque 36% of max revs and stays at that level to
> 90% of max revs.

So does my lawn-mower.

[Richard Wood]

"Steve Uzochukwu" <randombloke@genie.co.uk> wrote in message news:41ec52c5.17169310@News.Individual.NET...
> On Sun, 16 Jan 2005 05:01:26 -0000, "Richard Wood" <news2@ukrm.co.uk>
> wildly wibbled thus:
>
> >"Steve Uzochukwu" <randombloke@genie.co.uk> wrote in message news:41e9b236.56947543@News.Individual.NET...
> >> On Sat, 15 Jan 2005 11:02:32 -0000, "Richard Wood" <news2@ukrm.co.uk>
> >> wildly wibbled thus:
> >>
> >> >Can I just say at this moment that I have absolutely no ****in clue what
> >> >the difference is between torque and HP apart from torque occurs
> >> >lower in the revs and bikes feel good when revving high so I likes
> >> >HP more, and the higher the numbers the better...
> >>
> >> Not the owner of a direct injection diesel then?
> >
> >I'm with JC on diesels...
> >
>
> but surely, you're nice bloke, and he's a [fill in randon selection of
> abusive terms here], as well as being prejudiced and not current.

(just to be sure, jeremy clarkson...)

He's funny, doesn't suck up to all the manufacturers who submit cars to
be ridiculed (apart from Ford when he wanted one, and even then it was
piss taking), and IMHO a lot is clever BS to keep people interested.

As to diesel, well, its dirty, smelly, stuff. Euck.


frag

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> saying something like:

>>>On the other hand the gearbox acts as a torque converter.
>>
>>Uhuh.
>
>OK stepped torque converter.
>>
>>>Increasing the RPM and reducing the torque.
>>
>>Aherm. Been at the Tanglefoot again?
>>
>You with Ace on this one then?

Certainly not; the subject is reduction boxes.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Mick Whittingham]

In article <aegqu05h0s08gahos9puadtba42qfck8bg@4ax.com>, Grimly
Curmudgeon <grimlycurmudgeon683@hotmail.com> writes
>It was somewhere around Barstow, on the edge of the desert, when the
>drugs began to take hold. I remember Mick Whittingham
><Mick@whittinghamsite.fsnet.co.uk> saying something like:
>
>>>>On the other hand the gearbox acts as a torque converter.
>>>
>>>Uhuh.
>>
>>OK stepped torque converter.
>>>
>>>>Increasing the RPM and reducing the torque.
>>>
>>>Aherm. Been at the Tanglefoot again?
>>>
>>You with Ace on this one then?
>
>Certainly not; the subject is reduction boxes.
>
OK
After a reduction in RPM which has increased the torque for the same
power (less transmission losses) each gear provides a new ratio to the
torque / RPM value, maintaining that power value (Constant?) available
at that RPM at the crank.
--
Mick Whittingham
'and I will make it a felony to drink small beer.'
William Shakespeare, Henry VI part 2.

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Mick Whittingham
<Mick@whittinghamsite.fsnet.co.uk> saying something like:

>>>>>Increasing the RPM and reducing the torque.
>>>>
>>>>Aherm. Been at the Tanglefoot again?
>>>>
>>>You with Ace on this one then?
>>
>>Certainly not; the subject is reduction boxes.
>>
>OK
>After a reduction in RPM which has increased the torque for the same
>power (less transmission losses) each gear provides a new ratio to the
>torque / RPM value, maintaining that power value (Constant?) available
>at that RPM at the crank.

Yes, yes, yes, but what happened to the crocodile?

This bit 'ere...

>>>>>Increasing the RPM and reducing the torque.

Was more fitted to an (enlargement, expansion, extension, swelling) box.

**** nose what's the antonym of a 'reduction box'.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Simian]

Mick Whittingham wrote:
> When I was working on a competition saloon car in the late 60's early
> 70's with the genius in the subject who was preparing it:
>
> After looking at the torque and power curves off of the dyno he decided
> to reduce the 45 DCOE Webers for 40s.
> Along with other mods it dropped the max HP a tad but nearly double the
> width of the torque curve.
> The effect on the track times was a significant reduction.
> All to do with matching the engine to the gear box and vice verca plus
> what you want to do with it.

Tricky things, engines.

Moving from 39mm CV to 41mm flatslides lost a lot of the low midrange power
from my 7R, but added a wodge-load above 9,000rpm. Below 4000 it's running
fairly rich (so you can start it, what with there being no choke), but from
4000-8000 it's all about how good you are at matching throttle opening to
engine revs... and unfortunately it's me riding it.

Actually, I'm beginning to wonder whether I ought to just program the throttle
to, at most, match the revs, below 8000, but that seems like cheating, and
hard work.

Incidentaly, one of the reasons that McLaren did so badly last season in F1
was because Mercedes removed the per-track engine tuning feature, which
allowed the team to soften the power output at various points in the rev
range that coincided with tricky corners etc.

--
ZX7RR.

[Simian]

Ace wrote:
> On Sat, 15 Jan 2005 22:44:54 -0000, Simian
><Simian@in_valid.semi-evolved.org> wrote:
>
>>Ace was saying that torque was important, not power,
>
> Oi! That's twisting my words. my point was, and is, that it's torque,
> not power, that forms as an absolute measure of the amount of
> acceleration available. As previously quoted, a=T/I
> (acceleration=Torque/Inertia).

Actually, acceleration = power / (mass * speed)

[ Thus:

force = mass x acceleration

and

energy = force x distance

and

power = energy / time

so

force = energy / distance

with

energy = power * time

gives

force = power * time / distance

we all know that speed = distance / time, so

force = power / speed

going back to the beggining

power / speed = mass x acceleration

leads us to

acceleration = power / (mass * speed) ]


Which tells you explicitly, that, independant of wind resistance, the
ability of a bike to accelerate is dependant on how much it weighs,
how fast it is all ready going, and what power the engine can output.

You've been convinced that torque is gearable, so I'll leave it there.



--
ZX7RR.

[sweller]

Simian wrote:

> Incidentaly, one of the reasons that McLaren did so badly last season
> in F1 was because Mercedes removed the per-track engine tuning feature,

Do you know why Mercedes chose to do this?

--
Simon

http://www.sweller.co.uk/sob/

[Grimly Curmudgeon]

It was somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember "Richard Wood" <news2@ukrm.co.uk>
saying something like:

>As to diesel, well, its dirty, smelly, stuff. Euck.

Biodiesel isn't. Got a delightfully light nutty smell with just a whiff
of summer breeze. When you burn it, it smells like the back of a bakery
where doughnuts are being made.

--

Dave

GS 850 x2 / SE 6a
SbS#6 DIAABTCOD#16 APOSTLE#6 FUB#3
FUB KotL OSOS#12? UKRMMA#19 COSOC#10

[Simian]

sweller wrote:
> Simian wrote:
>
>> Incidentaly, one of the reasons that McLaren did so badly last season
>> in F1 was because Mercedes removed the per-track engine tuning feature,
>
> Do you know why Mercedes chose to do this?
>

I can't really remember - I've got a vague recollection of having the
feeling that it sounded like they'd made a bit of a cock up designing
the engine, and ran out of time, and so cut the features they decided
weren't important.

I was fairly drunk at the time...

--
ZX7RR.