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Calcimator

Quarter-Mile ET Predictor Calculator

Elapsed time from weight and horsepower.

Inputs

%

Results

Quarter-mile ET (sec)

13.54

Trap speed (mph)

100.7

60-ft time (sec)2.06
Est. 0-60 mph (sec)6.36
1/8-mile ET (sec)8.56
1/8-mile speed (mph)82
Wheel HP255
Lbs per WHP12.55
How to Use This Calculator
  1. Enter Vehicle weight (lbs), Flywheel HP, and Drivetrain loss (%).
  2. Set Tire type (0=street, 1=slick).
  3. Review Quarter-mile ET (sec) and Trap speed (mph).
  4. Use 60-ft time (sec) and Est. 0-60 mph (sec) to inform your decision.

How the result changes with Flywheel HP

Flywheel HPQuarter-mile ET (sec)Trap speed (mph)
54511.09122.9
1,7837.47182.4
3,2686.11223.2
4,5055.49248.4

What each input means

Vehicle weight (lbs)
Total vehicle weight including driver (curb weight + ~170 lbs).
Flywheel HP
Flywheel (crank) horsepower as rated by the manufacturer or measured on an engine dyno.
Drivetrain loss (%)
Typical losses: 15% manual, 18% automatic, 10% direct drive / EV.
Tire type (0=street, 1=slick)
Street tires have higher 60-ft times; drag slicks improve launch.

What each result means

Quarter-mile ET (sec)
Predicted elapsed time using ET = 5.825 × (W/WHP)^(1/3).
Trap speed (mph)
Estimated speed at the end of the quarter mile.
60-ft time (sec)
Estimated 60-foot launch time based on tire type.
Est. 0-60 mph (sec)
Rough 0-60 estimate from quarter-mile ET.
1/8-mile ET (sec)
Eighth-mile elapsed time (ET × 0.632).
1/8-mile speed (mph)
Estimated speed at the 1/8-mile mark.
Wheel HP
Horsepower at the wheels after drivetrain loss.
Lbs per WHP
Weight-to-power ratio used in the calculation.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Vehicle weight (lbs) = 3200, Flywheel HP = 300, Drivetrain loss (%) = 15, Tire type (0=street, 1=slick) = 0 = 4 input(s) provided
  2. Calculate Quarter-mile ET
    Quarter-mile ET = 5.825 * pow(wpr, 1 / 3)
    13.536 = 13.536
  3. Calculate Trap speed
    Trap speed = 234 / pow(wpr, 1 / 3)
    100.7 = 100.7
  4. Calculate 60-ft time
    60-ft time = etSeconds * sixtyFootFactor
    2.058 = 2.058
  5. Calculate Est. 0-60 mph
    Est. 0-60 mph = etSeconds * 0.47
    6.36 = 6.36

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