1. What is an 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:

• \( ET \) — 1/4-mile elapsed time (seconds)
• \( W \) — Vehicle weight (pounds)
• \( HP \) — Engine horsepower

Explanation: The formula calculates the cube root of the weight-to-power ratio and scales it to approximate quarter-mile times.

3. Importance of ET Calculation

Details: Quarter-mile time is a standard performance metric in drag racing and automotive testing.

4. Using the Calculator

Tips: Enter the vehicle's curb weight 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, aerodynamics, gearing, and driver skill.

Q2: Should I use wheel horsepower or crank horsepower?
A: For best results, use actual wheel horsepower (dyno-tested) rather than manufacturer's crank ratings.

Q3: Does this include driver weight?
A: No, add driver weight to the vehicle's curb weight for more accurate results.

Q4: What's a good quarter-mile time?
A: Street cars typically run 13-15 seconds. Performance cars run 10-12s. Pro dragsters run under 7s.

Q5: Can I calculate trap speed too?
A: Yes, trap speed ≈ 234 × (HP/W)^(1/3) mph, but this calculator focuses on ET.