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If you consult your latest dyno chart measuring rear-wheel performance, you should find that this equation doesn't accurately describe the torque and power trends you see. The equation is only really applicable to a brake-dyno chart. Quickly stated (because this topic has also been beaten to death on this forum), on a brake dyno, measurements are taken at constant engine speed, allowing the "true" work of an engine to be measured. (This is not the actual work of the engine, because there are also friction losses in the engine which require a different test to measure, but are ultimately irrelevant unless you're developing new equipment to minimize friction losses) In the constant engine speed case, the equation relating torque and horsepower can be safely used to relate the output torque and output horsepower of the engine. In the case of a rear-wheel dyno, or whatever it has come to be called around here, at any given moment, the output of the engine IS in fact related to the torque in the previously specified manner. However, that torque value is also responsible for accelerating the internal engine parts, transmission parts, driveshaft(s), differential gears, wheels, engine peripherals, etc. Whatever engine torque happens to be left over is all that's left to accelerate the car. Now I could be wrong about this next part, but considering two otherwise equal cars, one with a high-revving engine, and one with a low-end-torque engine, I think both would have the same instantaneous acceleration at a given speed, if their engine torques were identical at that moment...regardless of engine speed. The real difference is what happens in the next instant though, if the low-end car is huffing out, it's acceleration will drop whereas the high-end car might continue to accelerate constantly. For a drag car, you obviously wouldn't put monster turbos on, that would take two seconds of WOT to spool up, nor would you want an engine with riculous low-end torque that couldn't breathe past 3500rpm. If you were at an 1/8 mile drag, a low end car would do better probably. On a 1/4 mile, you'd want more breathing ability. Of course, gearing becomes an issue, and the possibility of lowering your ratios might keep you higher in the powerband, but if you get too extreme you'll find yourself needing an extra shift to reach the checkers. Concerning the Datson 510 example you mentioned, there must have been some miscommunication concerning RWHP numbers or brake dyno numbers. Not presuming to know anything about the parasitic losses of a rotary engine, making some gross generalizations and generous allowances, an engine with torque numbers like that would need to reach almost 15000rpm to hit 500hp. If the torque "fell" after a certain point, that is characteristic of having been measured on a brake-dyno. Or maybe the engine has a seriously bizarre power curve. When discussing its strip times, we should also bear in mind that a 510 weighs about half that of a stock Z32. So in the end, power is kind of a B.S. quantity, because all it's doing is measuring your instantaneous rate of torque delivery. After all, one engine operating at a certain parameter is delivering the same power as another engine with twice the torque but doing it half as fast. What's really imoprtant is the shape of the torque and power curves. That's all my brain can muster right now. Keep us posted on your findings, and musings :)
-------------------------------------------------------------------------------- "Let's make like a baby and Head Out" - Jimmy "Funk you very much" - George Clinton "If I had a million dollars? ...two chicks at the same time"
SoCal... Stoked not to be NorCal
 
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00:44:21 01/20/04
