Thread: drag racing facts

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Skids, next time you're watching an NHRA event on the tube, especially the final round in the evening, watch the top fuel cars. Everytime there is a flame out of a header tube that's a cylinder firing. When the car launches you can't see the pulses, just one solid flame out each cylinder that is still burning.... There is far more slippage due to clutching and tire spin then you would ever think. If you ever get near a top fuel team computer and can look at the run data you will clearly see that drive shaft rpm and engine rpm aren't even close to the same as your calculations would assume they are. Even in top alcohol, the clutch at launch on the first set of arms was in excess of 40% slippage, on a bad track, even lighter clutch loads then that. I've never driven a top fuel car, but even in our much lower horsepowered alcohol cars and then only on a perfect track with perfect conditions you were at full lockup on the clutch for MAYBE the last hundred feet of the quarter.....

I doubt today's top fuel cars are ever at full lockup on the clutch.....

I'm far from being a mathematics whiz, but your equation would be closer to accurate if the top fuel car were at a constant speed, and not at a stand still. In a bracket car, with four or five forward gears, the velocity and rate of acceleration, gear ratio, clutch and converter slippage, tire spin and a bunch of other variables would have to come into the formula. As I said, with the car locked up at a 1:1 final drive ratio meaning the crankshaft and driveshaft rpm were equal and the gear ratio in the rear was 1:1 then it would be accurate. Just because the engine only runs for X seconds at X rpm is not an accurate portrayal of how many times each cylinder must fire.....The crankshaft and the rear axle are never at the same rpm, which your formula would seem to assume......