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Old 06-20-2006, 02:45 PM   #39
blue2000s
Porscheectomy
 
Join Date: Mar 2006
Location: Seattle Area
Posts: 3,011
Quote:
Originally Posted by insite
blue, this is not true. force means nothing without MOTION. force that causes motion is WORK. work performed quickly is POWER.

Example: you have 2 identical cars w/ different torque curves. both cars are currently making 300 ft-lb of torque.

Car A: Torque = 300 ft-lb, RPM = 8000, HP = 457
Car B: Torque = 300 ft-lb, RPM = 4000, HP = 228

now, as you stated earlier, because these cars are making equal torque, they are accelerating at equal rates. BUT, assuming 1:1 final drive: car A is doing this from 91 mph while car B is doing this from 45 mph. even though they are gaining speed at the same rates, car A is travelling MUCH faster because it is performing WORK at twice the rate (double the POWER).

it is a common misconception that shifting just above peak torque will yield fastest acceleration times. gearing allows us to take advantage of power, though, and the object is to do the WORK (i.e. move 3000 lb of car 1/4 mile) as quickly as possible. work / time = power.

I wouldn't argue against that at all. but the acceleration of the vehicle still comes from torque doesn't it? That's all I've been saying.

What you are saying is that there is an advantage to acceleration in extended speed, this is certainly true, but this is still due to the conversion of that speed to torque at the wheels through gearing. It all comes back to torque. READ THE BOOK!

Last edited by blue2000s; 06-20-2006 at 02:49 PM.
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