1. What is the Quarter Mile ET Equation?

The Quarter Mile ET (Elapsed Time) equation estimates the time it takes for a vehicle to complete a quarter mile (1,320 feet or 402 meters) drag race. This calculation is widely used in automotive performance testing and racing to predict vehicle acceleration capabilities.

2. How Does the Calculator Work?

The calculator uses the Quarter Mile ET equation:

Where:

• \( ET \) — Quarter Mile Elapsed Time (seconds)
• \( Weight \) — Vehicle weight (pounds)
• \( HP \) — Engine horsepower
• \( 5.825 \) — Empirical constant
• \( 1/3 \) — Cube root exponent

Explanation: The equation demonstrates the cubic relationship between power-to-weight ratio and acceleration time, showing that doubling the horsepower doesn't halve the ET due to diminishing returns.

3. Importance of Quarter Mile Time Calculation

Details: Quarter mile time is a standard performance metric in automotive racing and testing. It provides a comprehensive measure of a vehicle's acceleration capabilities, combining both engine power and vehicle weight factors.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and engine horsepower. Both values must be positive numbers. The calculator provides an estimated quarter mile elapsed time in seconds.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this equation?
A: This equation provides a good estimate for most production vehicles, but actual performance can vary based on traction, transmission, aerodynamics, and driving technique.

Q2: What is considered a good quarter mile time?
A: For street-legal production cars, under 14 seconds is good, under 12 seconds is excellent, and under 10 seconds is exceptional. Professional dragsters can achieve times under 5 seconds.

Q3: Does this account for driver weight?
A: No, this calculation uses vehicle weight only. For more accurate results, include driver and passenger weight in the total weight calculation.

Q4: What factors affect quarter mile times besides weight and horsepower?
A: Traction, tire type, transmission efficiency, aerodynamics, altitude, temperature, and track conditions all significantly impact actual quarter mile performance.

Q5: Can this be used for motorcycles?
A: While the basic principle applies, motorcycles have different power delivery and traction characteristics, so results may be less accurate for two-wheeled vehicles.