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Originally Posted by swamp2
That is not a problem with the statement. A limitation perhaps but fairly minor. Just abstract one level further and realize that we are talking about ANY speed. You can also imagine the rule being applied to two cars both beginning at the same speed - a basic rolling drag race. The one with that can develop the most power (well best power to weight actually) will initially out accelerate the other. Once the speeds become appreciably different you can't use the exact same rule/formula. For this you need a full dynamic time domain simulation.
Absolutely, should have stated the first assumption on traction. Sort of felt it was obvious/implied but it wasn't. Also as far as friction you mean losses right? I am talking about dissipation in the tire itself from its cyclic deformation. Some of that mechanism is certainly frictional but we are not talking about tire on road friction.
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Correct. If that was the intent of the statement then I agree. However, I fear people may read it and think that peak power for a set speed can be manipulated without changing gear ratios.
I think a more accurate statement would be "Peak acceleration occurs at the point where a given powerplant produces peak power (torque) while utilizing the shortest (numerically highest) possible gear ratio"
Speed is an afterthought in this discussion since it is a simple byproduct of engine rpm and gear ratios.
Quote:
Originally Posted by Wall$treet
Swamp I have read your great informative posts on this topic on other threads as well and its good stuff. However I think you need to be more specific when you say the word torque. Most people just look at engine torque and neglect WHEEL torque as the force which accelerates the car. As I have mentioned before a real easy conceptual way to understand things is that engine torque and RPM's both create power from the engine. The gearing transfers that power to the wheel in multiples based on gears and that creates wheel torque to accelerate the car.
At lower RPM's, the engine torque is more important since RPM's are not high enough to create power. That is why the m3 is a bit slower off the line. At high revs it is a combo of engine torque and RPM's. Even though engine torque declines after 7k, the increasing RPM's more than make up for that and overall net power continues to increase until 8300. Then after that the car is at the limits of its camshafts and setup, thus you do nto make infinite hp with higher revs. The peak HP is when the wheels of the car are turning with the most torque force and acceleration
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you were right until you got to the second paragraph.