HP to ET Calculator

Elapsed Time Formula:

\[ ET = \left(\frac{W}{HP}\right)^{\frac{1}{3}} \times 5.825 \]

1/4-mile Elapsed Time (s):

Definition: This calculator estimates a vehicle's 1/4-mile elapsed time based on its weight and engine horsepower.

Purpose: It helps automotive enthusiasts and racers predict quarter-mile performance times without actual track testing.

The calculator uses the formula:

\[ ET = \left(\frac{W}{HP}\right)^{\frac{1}{3}} \times 5.825 \]

Where:

Explanation: The cube root of the weight-to-power ratio is multiplied by a constant factor (5.825) to estimate elapsed time.

Details: Accurate ET prediction helps in vehicle setup, performance tuning, and comparing different configurations.

Tips: Enter the vehicle weight in pounds and engine horsepower. Both values must be > 0.

Q1: How accurate is this calculation?
A: It provides a rough estimate. Actual ET depends on traction, gearing, aerodynamics, and driver skill.

Q2: Should I use curb weight or race weight?
A: For most accuracy, use the actual race weight including driver and fuel.

Q3: Does this account for drivetrain loss?
A: No, use rear-wheel horsepower if you know it for more accurate results.

Q4: What's a good ET for a street car?
A: 13-15 seconds is respectable, under 12 is very fast, and under 10 is exceptional.

Q5: Can I calculate horsepower needed for a target ET?
A: Yes, rearrange the formula: \( HP = W / (ET / 5.825)^3 \)