Horsepower 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 (ET) 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 an empirical constant (5.825) to estimate ET.

Details: Quarter-mile time is a standard performance metric in drag racing, helping compare vehicle acceleration capabilities.

Tips: Enter the vehicle's curb weight in pounds and the engine's 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 wheel horsepower or engine horsepower?
A: For most accurate results, use wheel horsepower (measured at the wheels).

Q3: Does this include driver weight?
A: No, add driver/passenger weight to the vehicle's curb weight for race weight.

Q4: What's a good 1/4-mile time?
A: Street cars: 13-15s, performance cars: 11-13s, drag cars: under 10s, F1 cars: ~9s.

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