Water-Cooled VW Performance Handbook

Calculate ¼-mile ET and trap speed

If you know your vehicle weight in pounds and the dyno horsepower, you can use this on-line calculator to guestimate the ¼-mile elapsed time (E.T.) and trap speed in miles-per-hour.

Vehicle weight  
Dyno horsepower  
¼-mile ET   seconds
¼-mile speed   mph

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 117.08 miles-per-hour.

This calculator uses the following formulas:

Calculate ¼-mile ET from HP and weight:

\[ET = \left(\frac{Weight}{HP}\right)^.333 \times 5.825\]

Calculate ¼-mile trap speed from HP and weight:

\[MPH = \left(\frac{HP}{Weight}\right)^.333 \times 234\]

The results you obtain from this calculator are just guestimations, though. Front-wheel drive cars are different from rear-wheel drive cars, and all-wheel drive cars are different still.

To see the background of these formulas, see Earles L. McCaul’s analysis and evaluation.