Horsepower Equations Calculator

Automobile Car Truck Design Formulas

Problem:

Solve for the change or increase in engine or motor horsepower performance using the ET method.

This method uses the elapsed time needed to complete a quarter mile run. It is used to give an estimate of vehicle(car, truck, motorcycle) engine horsepower. Weight should include the mass of the vehicle, driver and passenger. Times will need to be measured before and after performance or after market parts have been installed.

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	Rotating horsepower
	Torque
	Speed - revolutions per minute (rpm)

	Estimate of engine horsepower after a quarter mile run using the trap speed method.
	Determine the increase in engine horsepower when an after market modification, race or performance part has been installed with trap speed.
	Calculate engine horsepower after a quarter mile run using the ET method.
	Compute estimated increase in engine horsepower when an after market, racing upgrade or performance part has been installed with ET.
	Dyno correction factor. Factor corrects horsepower for normally aspirated internal combustion engine to a standard humidity, pressure and temperature after dynamometer measurement.
	Calculate a vehicles power to weight ratio. Acceleration is related to the ratio.