Weight Horsepower Quarter Mile Calculator

Quarter Mile Performance Equation:

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

Elapsed Time (ET):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Quarter Mile Performance Equation?

The Quarter Mile Performance Equation estimates the elapsed time (ET) for a vehicle to complete a quarter mile drag race based on its weight and horsepower. This formula provides a theoretical performance benchmark for automotive enthusiasts and racers.

2. How Does the Calculator Work?

The calculator uses the quarter mile performance equation:

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

Where:

\( ET \) — Elapsed Time (seconds)
\( Weight \) — Vehicle weight (pounds)
\( HP \) — Engine horsepower
\( 5.825 \) — Empirical constant

Explanation: The equation calculates the cube root of the weight-to-power ratio, providing a theoretical quarter mile time that accounts for the fundamental relationship between vehicle mass and power output.

3. Importance of ET Calculation

Details: Quarter mile elapsed time is a standard performance metric in automotive racing. It helps enthusiasts compare vehicle performance, estimate potential race outcomes, and understand the impact of weight reduction or power increases.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and engine horsepower. Both values must be positive numbers. The calculator provides a theoretical ET that assumes ideal traction and driving conditions.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this equation?
A: This provides a theoretical baseline. Actual performance depends on traction, aerodynamics, transmission efficiency, and driver skill.

Q2: What is a good quarter mile time?
A: Times vary by vehicle type: 14+ seconds for average cars, 12-13 seconds for performance cars, and sub-10 seconds for dedicated drag vehicles.

Q3: Does this account for drivetrain loss?
A: No, use wheel horsepower for more accurate results rather than engine horsepower to account for drivetrain losses.

Q4: Can I use this for motorcycles?
A: Yes, though motorcycle aerodynamics and traction characteristics differ from cars, so results may vary.

Q5: What factors affect actual quarter mile times?
A: Traction, weather conditions, altitude, tire pressure, launch technique, and vehicle aerodynamics all significantly impact actual performance.