[dbiscayne]

All the formulas that figure out what your trap speed and ET and horsepower need to be, are they using flywheel horsepower or rear wheel horsepower?

 

[igo1090]

usually rwhp since they dont know the actual setup of the car with respect to friction losses in the powertrain. they tell you the hp after all the parasitic losses.

 

[ckelly]

RWHP And the ET calcs are pretty worthless. MPH and weight are the only thigns that come close.

 

[igo1090]

actually, 1/4 mile mph and car weight will give a good est of rwhp. then there are minimumet et charts for a given mph which are estimates. these are tools which can help you get a handle on your combo & help you optimize your combination. their figures are not carved in granite, but are ballpark approximations which can be useful.