Performance Formulas

Convert between 1/4 mile and 1/8 mile ET's

   1/4 mile ET = 1/8 mile ET x 1.5832 (thanks to Bobby Mosher for this formula)

   1/8 mile ET = 1/4 mile ET / 1.5832 (thanks to Bobby Mosher for this formula)

Calculate 1/4 mile ET and MPH from HP and Weight

   ET = ((Weight / HP)^.333) * 5.825

   MPH = ((HP / Weight)^.333) * 234

Calculate HP From ET and Weight

   HP = (Weight / ((ET/5.825)^3))

Calculate HP From MPH and Weight

   HP = (((MPH / 234)^3) * Weight)

Formulas for displacement, bore and stroke

pi/4 = 0.7853982

cylinder volume = pi/4 x bore^2 x stroke

stroke = displacement / (pi/4 x bore^2 x number of cylinders)

Formulas for compression ratio

(CylVolume + ChamberVolume) / ChamberVolume

cylinder volume = pi/4 x bore^2 x stroke

chamber volume = cylinder volume / compression ratio - 1.0

displacement ratio = cylinder volume / chamber volume

amount to mill = (new disp. ratio - old disp. ratio / new disp. ratio x old disp. ratio) x stroke

Formulas for MPH RPM gears & tires

mph = (rpm x tire diameter) / (gear ratio x 336)

rpm = (mph x gear ratio x 336) / tire daimeter

gear ratio = (rpm x tire diameter) / (mph x 336)

tire diameter = (mph x gear ratio x 336) / rpm