1. What is a 1/4 Mile ET Calculator?

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.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( ET \) — Elapsed time (seconds)
• \( W \) — Vehicle weight (pounds)
• \( HP \) — Engine horsepower

Explanation: The cube root of the weight-to-power ratio is multiplied by a constant factor (5.825) derived from empirical drag racing data.

3. Importance of ET Calculation

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

4. Using the Calculator

Tips: Enter the vehicle's curb weight (including driver) in pounds and the engine's horsepower. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It provides a theoretical estimate. Actual times vary based on traction, gearing, aerodynamics, and driver skill.

Q2: Should I use wheel horsepower or engine horsepower?
A: For most accuracy, use wheel horsepower (measured at the wheels) which accounts for drivetrain losses.

Q3: Does this include reaction time?
A: No, this calculates only the vehicle's elapsed time from launch to finish.

Q4: What's a good 1/4 mile time?
A: Times vary by vehicle type: 10-12s for performance cars, 13-15s for sports cars, 16-18s for average passenger vehicles.

Q5: Can I calculate trap speed with this?
A: No, this only calculates elapsed time. Trap speed requires a separate calculation.