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.
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 = ((Weight ÷ HP).333) × 5.825
Calculate ¼-mile trap speed from HP and weight:
MPH = ((HP ÷ Weight).333) × 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.