No small torque.

[Mikkel]

'Torque' allows you to drive out of a corner faster. You then carry more speed down the straights. This is turn, allows you to produce better lap times. Better lap times than the people you're racing allows you to win said race.

For a given engine operating at a certain speed (RPM) the following is true: More torque -> more power.

I hope we can at least agree on that!

The only way to produce more power without more torque is by moving up the redline.

If all that mattered was torque I believe we should see more singles in the motoGP and superbike fields.

For roadracing, engines are engineered and tuned for maximum power. True enough, to achieve this you have to maximise this you'll have to match your torque curve so that you have your peak torque in upper part of the RPM range. If this was not the case you would see quite different engines with quite different stroke/bore ratios!

And there you have it. F1 cars (as you've mentioned) used to be turbo charged. They got too fast.

Indeed they got so fast that they became too dangerous for the organisation to stomach... But turbos increase power by increasing torque. HINT: I'm not arguing that more torque is a bad thing - only that it's not the torque figure that is important, it's the power output that matters. However, you can not have power without torque. (Did you read that bit or did you just quote it?)

100% BULLSHIT.

Finally a good argument, could you provide any references?

In my opinion, what Mikkel said is 0% bullshit.

Perhaps if you could be more specific about what you disagree with we could get somewhere?

Thanks mate, but I doubt KB is the right forum for a sober debate on just about anything...

Be that as it may - A road bike with lower power and more torque is better than a road bike with big power and low torque.

No, it's a slower road bike that requires less work to ride. It's not a race bike though.

Of course a torque vs rpm and an HP vs rpm graph contain exactly the same info. They're both relative, and are both showing when and where max output occures in the rev range.

Well, there's supposedly a scale on the y-axis of said graphs. As such you should hopefully be able to extract some quantitative information from said graphs - they are not relative...

Torque is the derivative of power with regards to engine speed. As such the torque curve will tell you where the power increase as you increase your engine speed is the highest. Or where you'll accelerate the fastest when you crank the throttle.

We don't care too much about the torque since we use gearing to adjust it up or down as is convenient. We can not adjust the power in the same way - what is there is all we have to work with, no matter how fast we are moving.

What I said was 'torque' wins races, HP claims are wank fuel.

Have you not ever noticed how the guys riding the GP bikes all want better 'drive' out of the corners?

Why? So they can do better lap times. TORQUE.

True enough, there's a lot of wanking going on about power figures. However, the reasons for the factories to stop publishing power figures is that a power figure can lie - having the highest peak power does not make for the most enjoyable bike. Indeed if the peak is too narrow it won't even be a fast bike (as in acceleration).

However, the argument that you present above is rather flawed. Saying that torque gives better lap times because it gives more drive out of the corners without reference is hardly debating the subject.

Let me put this question to you then, consider:
Engine A - redlines at 5,000 RPM puts out a massive 400 Nm at 2,500 RPM and maintains that torque until redline.
Engine B - redlines at 20,000 RPM, puts out 100 Nm at 10,000 RPM and maintains that torque until redline.
Which engine is faster?

Nope - banned or not developed in the right areas is how i feel about diesels.
They were told they couldn't race in the BTCC.
Bikes only got non-performance diesels.
Trucks and BF-vehicles get some of the high horsepower stuff.
Saying the diesels are non-performance clappers is like saying the only good 2-strokes are in vespas.
2-stroke turbo diesels are nuts, make turbine engines feel like they are a waste of time....

That's a bloody shame really! I wonder why they have made that call...

[madandy]

Wow! escalated into another HP v's Torque 'debate' it did.
I love HP you CANNOT get high HP with out having high TORQUE at high RPM. Relative to the actual figures that is.
in 2005 an aussie car mag tested a 2L TDI mk5 Golf v's a 2L FSI petrol mk5 Golf. the gas car had 110kw @ about 5000 rpm and 200NM @ about 3000rpm the Diesel 103Kw at about 3500rpm and 320Nm @ 1800rpm.
The diesel car, despite being 40 odd kg heavier than its petrol powered sibling, trounced the petrol car in feats of accelleration 0-100, 0-400m, 80-120, every where... More torque and slightly less HPwon that race. Hmmm.

A mate has a mid '90's ZX6R and riding up a hill in top or even a gear down my bike destroys his. By the time he finds 3rd and gets his low(er) torque at high(er) rpm engine into its best rpm range I am long gone.
Now if you ride around in a low gear at 7-8000rpm you have all the engine performance at your disposal...and you're also gonna meet Bubba in the showers real soon.
Sure that ZX6R will kill my Duke in outright pace but it'll have to be wrung out to do that and I see plenty of evidence to suggest that experienced, mature and responsible riders tend to prefer loads of mid range torque over absolute HP...
GSXR1000 (for example) has loads of torque and can keep making =strong torque opnce the rpm goes into double digits...bikes like that are a great balance of torque and power - for those responsible enough.

I think some here are only looking at the peak figures rather than the area 'under the curve' and also talkin absolutes where some here are talking real world and that's where most of the confusion or failure to agree stems from...are we arguing semantics?

HP is great, but the greatest rush comes from high torque and an engine that can keep on making high torque as the tacho winds round into the FUN ZONE
Whatever you ride, it's torque that turns ya wheels
hp is a number calculated from measure torque at x rpm and relates to an engines' cylinder heads ability to breathe at increasing rpm...you're clever, you know the equation

[Badjelly]

Of course a torque vs rpm and an HP vs rpm graph contain exactly the same info. They're both relative, and are both showing when and where max output occurs in the rev range.

F**k this is frustrating. You're a rider and a racer and you know that "torquey" engines get you out of corners. I don't disagree with that (and neither, I think, does Troy Bayliss). But Mikkel and I have a background in science and engineering--geeks, basically--and are trying to get across something about the technical meaning of the word torque.

Let me put it this way: Imagine two hypothetical engines, both weigh the same, both develop the same maximum power and both have power curves of exactly the same shape. But one has max power at 6000 rpm (call this a petrol engine, if you like) and the other has max power at 3000 rpm (call this a diesel engine if you like). Now, the maximum torque of the second (diesel) engine will be twice the maximum torque of the first (petrol). Assume that when you put these engines in a vehicle you give the diesel engine gear ratios that are taller by a factor of exactly 2. And this will exactly compensate for its higher torque. The result is that in any gear at any speed, the maximum force the engine can exert on the road will be the same. So the two engines will have the same performance and will feel equally "torquey".

So what I'm suggesting is that the word "torque" has two meanings. One is the technical one and the other is the popular one and it really means "flexible power delivery". There's endless scope for confusing the two. (And manufacturers of diesel engines like to exploit this confusion.)

[Badjelly]

Thanks, madandy. No I'm not arguing semantics, I'm trying to clarify semantics to short-circuit the argument.

[imdying]

I love HP you CANNOT get high HP with out having high TORQUE at high RPM.

Of course you can... whatever you've got in mind, half the torque and double the RPM. Same high HP figure that you were thinking of, from 'low' torque.

[madandy]

F**k this is frustrating. You're a rider and a racer and you know that "torquey" engines get you out of corners. I don't disagree with that (and neither, I think, does Troy Bayliss). But Mikkel and I have a background in science and engineering--geeks, basically--and are trying to get across something about the technical meaning of the word torque.

Let me put it this way: Imagine two hypothetical engines, both weigh the same, both develop the same maximum power and both have power curves of exactly the same shape. But one has max power at 6000 rpm (call this a petrol engine, if you like) and the other has max power at 3000 rpm (call this a diesel engine if you like). Now, the maximum torque of the second (diesel) engine will be twice the maximum torque of the first (petrol). Assume that when you put these engines in a vehicle you give the diesel engine gear ratios that are taller by a factor of exactly 2. And this will exactly compensate for its higher torque. The result is that in any gear at any speed, the maximum force the engine can exert on the road will be the same. So the two engines will have the same performance and will feel equally "torquey".

So what I'm suggesting is that the word "torque" has two meanings. One is the technical one and the other is the popular one and it really means "flexible power delivery". There's endless scope for confusing the two. (And manufacturers of diesel engines like to exploit this confusion.)

So you read my post? ABout the diesel golf thrashing the petrol golf?
You technical guys are always right - like teachers.
We know what torque is...I don't beleive anyone was arguing the precise, intellectual, factual deffinition of torque. Rather that a 'torquey' bike is sooo much cooler than some screaming fucking banshee wailing it's way around the tacho, bent over the tank trying to get past the top gear rolling hill destroying grunt machine ridden by the guy with a great big grin on his face

haha

[Big Dave]

No, it's a slower road bike that requires less work to ride. It's not a race bike though.

What part of 'a road bike' did you miss?

[Badjelly]

Torque is the derivative of power with regards to engine speed.

Er, no. It's the power divided by the engine speed. The same units, but not the same thing.

[Badjelly]

So you read my post? About the diesel golf thrashing the petrol golf?

Yes, but only after I wrote my post.

My hypothetical diesel has exactly the same-shaped power curve as my hypothetical petrol engine. I'm not sure that this applies to your Golfs.

[imdying]

I don't beleive anyone was arguing the precise, intellectual, factual deffinition of torque. Rather that a 'torquey' bike is sooo much cooler than some screaming fucking banshee wailing it's way around the tacho, bent over the tank trying to get past the top gear rolling hill destroying grunt machine ridden by the guy with a great big grin on his face

You can't argue that... it's subjective tripe.

I've got two bikes, one a screaming banshee, and the other a vtwin thou... which one is better and gives better grins depends on:
- The weather
- What mood I'm in
- Who I'm riding with
- The direction of the wind
- What time the moon rises
- etc etc etc

Neither is 'better' or 'gives a bigger grin'. They're both good, and both give big grins. Anyone that thinks only a motorcycle with large amounts of torque low torque can give big grins is deluded.

[Badjelly]

You technical guys are always right - like teachers.

Thank you

[madandy]

Of course you can... whatever you've got in mind, half the torque and double the RPM. Same high HP figure that you were thinking of, from 'low' torque.

You ommitted the second sentence: "Relative to the actual figures that is."
I'm well aware of the rpm factor
Just sold my banshee GSXR750 and have the Duke...gixxer aint half the road bike the twin is but I agree with yuo wholeheartedly than in certain situations the banshee is one hell of a ride - when you're in total HOON mode

[madandy]

Yes, but only after I wrote my post.

My hypothetical diesel has exactly the same-shaped power curve as my hypothetical petrol engine. I'm not sure that this applies to your Golfs.

Fair enough.
Which real world engines would it apply to?

[Big Dave]

You can't argue that... it's subjective tripe.

Bike A: a ROAD bike with 100hp and 50 ft lbs (just pretend numbers for eg)

Bike B: 160 hp and 50 ft lbs

I'm taking the bike A every time.

I know where bike B develops that power and at what speed and know I won't be using it long. It turns to a whole mess of red and blue.

Torque is much better.

[Mikkel]

What part of 'a road bike' did you miss?

If you re-read it you'll see I didn't miss it at all. I just pointed out that it wasn't a racebike, and the reason for me doing so, was that when we start talking perfomance figures we'll inevitably edge towards racing as well.

Er, no. It's the power divided by the engine speed. The same units, but not the same thing.

Pardon the technobabble - ignore the following unless you appreciate such things, please.

Define k as the constant that makes the following equation

P = T*R/k

specify the relationship between power, P, torque, T, and angular frequency, R - for a given set of units. Then the following is true:

dP/dR = T/k

Choose your units so k = 1 and torque is indeed the derivative of power with regards to engine speed.

Would you not agree?


And the diesel golf vs. the petrol golf is irrelevant... VWs are crap!