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zanick is offline
Mar27-09, 12:34 AM
P: 49
Well, at least I have the effects on the road correct. :) thanks for that. thats most important, but just want to get the terminology right.

I think its coming into a philosophical debate now, which came first, the force or the power that created it. I think I understand, that even if the power creates the force, its the force that is causing the acceleration, even though the power of the act is known at the same time. (how is that for a compromise?).

So, how do we address the hp curve and the progressive time spent at different rpm as the engine accelerates over a given vehicle speed range when comparing different shaped HP curves of two engines, in the same car, with the same max HP?


Quote Quote by xxChrisxx View Post
But this thinking in horsepower is giving you a false sense of what is going on. The force on the rollers (that contributes to their acceleration) can be defined as a wheel torque.

As Torque = Force * distance.

So in this case the inertia and mass of the drum is known. The change in the speed of the drum in the amount of time is the acceleration. from this the force is known. From the size of the wheel the torque at the wheel is known.

So you see the torque is really still the measured 'thing'.

After the run up, the clutch is dipped and the run down lets you know the losses through the transmission. This will give you the torque at the flywheel. The revs are found from a tachometer iirc.

Well you werent 100% wrong, sorry for saying that. What i meant was, your reading of what was going on was wrong. Yours knowledge of how the rolling road works is spot on.