Torque/hp philosophy (infinant gear ratio)

  • Automotive
  • Thread starter hondaman520
  • Start date
  • #1

Main Question or Discussion Point

I am still trying to visualize horsepower and torque seen on the racetrack, and its hard. Obviously torque is a component of horsepower. Without enough torque, a car would take forever to reach its power-band. With a lot of torque, but merely no horsepower, a car would have a very steady acceleration curve, however, it would be slow.

so far correct?

I hear the car guys talking about how torque wins the races, (which annoys the **** out of me) when in reality, the truth to that is that smaller engine cars have a shorter powerband, and it takes longer to approach that powerband, when compared to muscle cars, correct?

Proposal:

What if in a completely theoretical situation, car had an infinitely variable gear ratio (such as a cvt), calibrated in a manner that kept the engine speed at its optimum powerband, regardless of the vehicle speed. So Im saying from a complete stop to a half mile, a vehicle goes full throttle while the computer adjusts the engine speed to remain at a constant rate.

Would torque be utterly useless in this fairytale situation? Obviously with no torque, it would be theoretically impossible to get something moving. But with negligible torque, could a small sized combustion engine with a significant amount of horsepower be used to tug a tractor, just as well as a larger sized diesel engine with the same hp output? (taking vehicle weight out of the equation)

This helps someone visualize that torque rating (on dyno sheets) is only useful for having a steady powerband for a duration of acceleration before changing gears. Which obviously on most production sports cars, is highly sought after.

This theoretical situation could shut up the torque enthusiasts, right? Obviously its only theoretical, but if you want a real life application of this, its called a race transmission. Many top end race cars have transmissions geared so close that they are merely in there powerband 100% of the time. Rendering bottom end torque not that important.


I MUST STRESS that I am only speaking relatively here. Its obvious with todays technology, performance cars need a good amount of torque to compensate for gear changes, ect. But consider the future, if we could design a continuously variable transmission strong enough to withstand lots of horsepower, and able to keep an engine at its optimum power band merely 100% of the time.

Please correct me if i'm wrong, and I would love discussing this, further.
 
Last edited:

Answers and Replies

  • #2
Another person from a similar thread said something that I thought was interesting:

Given a conventional geared transmission, supposedly best momentary acceleration is at peak wheel torque. This comes from F=MA, arranged as A=F/M. Acceleration is highest when force (torque) is highest.

Based on this viewpoint, optimal average acceleration would happen if an infinitely-variable, lossless continuously variable transmission kept the engine at torque peak throughout the acceleration run.


So to further reinforce my point, the optimal engine speed set by the theoretical governor would be set at the engines highest torque output, usually around 6-8000rpm in a smaller sized engine.

So it doesn't matter WHAT the peak torque is, as long as you have enormous amounts of horsepower, and you can stay in that range between max torque and max hp, your vehicle puts out a steady and vicious acceleration.

Acceleration is what racers want, as long as they have lots and lots of horsepower, and they can stay in their optimum engine powerband (at max torque output), engine torque is negligible.
 
  • #3
2,017
85
My god, not this again.

Why do you keep making threads waffling on about the same topic? This is exactly the same as the last two topics you've opened.

You set up a the single scenario where you can disregard torque output, and then try to extrapolate that to all situations. You also keep discussing torque and power as though they are in no way linked.



If you have a question, why can't you just ask it simply. So it can be answered and then you can stop asking repeat questions.
 
Last edited:
  • #4
My god, not this again.

Why do you keep making threads waffling on about the same topic? This is exactly the same as the last two topics you've opened.

You set up a the single scenario where you can disregard torque output, and then try to extrapolate that to all situations. You also keep discussing torque and power as though they are in no way linked.
Thats only because Im trying to come to a consensus among people.

I think I made 1 or 2 other threads about this, and that was several months ago, do you really loaf around the forums that much to give a f***? Cmon.
 
  • #5
2,017
85
Thats only because Im trying to come to a consensus among people.

I think I made 1 or 2 other threads about this, and that was several months ago, do you really loaf around the forums that much to give a f***? Cmon.
The threads are virtually identical. Just from a 'forum cleanliness' perspective, it may be better to bump the existing thread. That way you don't get the same thing posted over and over, as people can follow the discussion and progress can be made.

A new thread hits the reset button.
 
  • #6
2,017
85
When people re-quote 'power sells cars, torque wins races' and apply that to 'power is meaningless' most are misunderstanding a simple, but very eloquent phrase.
The phrase actually means, peak values are largely meaningless. It's how the engine operates throughout it's range.

Further to this, what you appear to discuss is engine operating range.
 
  • #7
The threads are virtually identical. Just from a 'forum cleanliness' perspective, it may be better to bump the existing thread. That way you don't get the same thing posted over and over, as people can follow the discussion and progress can be made.

A new thread hits the reset button.
ok ok ill give you that one, not a bad idea ill admit.

When people re-quote 'power sells cars, torque wins races' and apply that to 'power is meaningless' most are misunderstanding a simple, but very eloquent phrase.
The phrase actually means, peak values are largely meaningless. It's how the engine operates throughout it's range.

Further to this, what you appear to discuss is engine operating range.
I don't think they always misunderstand the meaning, but they limit their experience to traditionally geared transmissions, where nowadays aftermarket transmission suppliers are involving larger varieties of gearing/clutch setups. You can only argue torque theory so much, at least until someone shows up with a smaller engine that pulls harder primarily because of the high final drive and close geared transmission. While its certainly less common on the track, its still proving american muscle heads wrong.
 
  • #8
Evo
Mentor
23,104
2,450
Closed pending moderation.
 

Related Threads for: Torque/hp philosophy (infinant gear ratio)

  • Last Post
Replies
2
Views
5K
  • Last Post
Replies
6
Views
262
Replies
3
Views
2K
Replies
47
Views
3K
  • Last Post
2
Replies
29
Views
9K
Replies
4
Views
563
  • Last Post
Replies
14
Views
1K
  • Last Post
Replies
2
Views
1K
Top