Water-Cooled VW Performance Handbook

# Horsepower estimates from ¼-mile results

If you have access to a dragstrip and a vehicle scale, you can guestimate your engine horsepower — no dyno needed!

## Using trap speed and weight

If you know how fast your vehicle is traveling at the end of a quarter-mile run, you can calculate an estimated horsepower. That is, on the basis of your final speed through the traps, you can guestimate your engine horsepower.

Speed at the end of the quarter mile MPH pounds

For example, a 2,400 pound vehicle with 300 horsepower should make it through the quarter-mile in 11.65 seconds, with a trap speed of 117 miles-per-hour.

This calculator uses the formula:

$HP = \left(\frac{MPH}{234}\right)^3 \times Weight$

## Using ¼-mile time and weight

If you know how long it takes your vehicle to run a standing quarter-mile , you can calculate an estimated horsepower. That is, on the basis of your ¼-mile time, you can guestimate your engine horsepower.

Elapsed time in the quarter mile seconds pounds

For example, a 2,400 pound vehicle with a quarter-mile time of 11.65 seconds is making about 300 horsepower.

This calculator makes use of the formula:

$HP = \frac{Weight}{(ET \div 5.825)^3}$

Note: The results you obtain from these calculators are just guestimations, though. Front-wheel drive cars are different from rear-wheel drive cars, and all-wheel drive cars are different still.