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      12-06-2007, 08:58 PM   #178
lucid
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Drives: E30 M3; Expedition
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Quote:
Originally Posted by enigma View Post
Yes,

If you know engine HP at any given time, you can calculate acceleration as long as you also have weight.

If you know engine TQ, well, you cannot calculate jack without knowing a lot of additional information beyond weight.

Or put another way, knowing just a cars power to weight is an execellent approximation of acceleration. TQ/weight won't tell you a thing unless you also start talking about gearing and RPM at which point you know HP and could have just used it to start.
I agree with max Hp being the "correlate" for average acceleration since the max Hp figure contains information about the redline rpm. However, Tq will give you the instantaneous acceleration since F=ma at any time t. So it is Tq that allows you to make the instantaneous acceleration calculation not Hp since Tq=F x d. Instantaneous acceleration will follow the torque curve.

Quote:
Originally Posted by enigma View Post
But by all means continue to worship at the alter of engine TQ.
Not sure where this coming from? My point is the Tq vs. Hp distinction is not particularly meaningful since they are directly coupled. On the other hand, max Tq vs. max Hp distinction is meaningful.

Going back to Bruce's original statement: so how come the redline does not matter?
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