Horsepower Calculator
Over the years, we have learned that calculating a vehicle's power can be tricky business. Dyno's, are excellent tuning tools and can provide a relatively good approximation of power, however dyno's have several drawbacks. For Example an old or inproperly serviced dyno, can read too low or too high, also the operator of the dyno has the ability to manipulate resistance or "load" to obtain a specific reading. We recommend that that you utilize all options available to you to get the closest approximation of power, (get a dyno run and go to the track) but nothing beats the REAL DEAL. The calculator below uses the most common and accurate mathematical equation to figure your vehicle's horsepower numbers, keep in mind the numbers it shows are based on the information you provide. For an accurate reading MAKE SURE you enter the exact vehicle weight (including driver) for the run you got your trap speed from. This method as well has drawbacks which are worth mentioning, for example humidity from one day track day to the next can cause numbers to fluctuate. Remember both Dyno's as well as these calculators provide an ESTIMATE of horsepower being produced, not a definitive number.
There are two calculators presented below, one (the more accurate) utilizes the vehicles weight and velocity. The other uses the vehicles elapsed time (ET) on the quarter mile run.

UNIT UNIT TYPE UNIT USED DESCRIPTION 
VEHICLE WEIGHT MASS POUND (LB) The weight of the car, truck or automobile including the driver, passenger and accessories.
SPEED OR VELOCITY VELOCITY MILE/HOUR (MPH) The velocity or speed of a vehicle measured in the trap at the end of a quarter mile run.
HORSEPOWER POWER HORSEPOWER (HP) The amount of power the engine is capable of producing.





UNIT UNIT TYPE UNIT USED DESCRIPTION 
VEHICLE WEIGHT MASS POUND (LB) The weight of the car, truck or automobile including the driver, passenger and accessories.
ELAPSED TIME (ET) TIME SECONDS The time it takes to complete a quarter mile run. The time it takes from start to finish.
HORSEPOWER POWER HORSEPOWER (HP) The amount of power the engine is capable of producing.




 USEFUL FORMULAS

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


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