1. What is the HP to Weight Equation?

The HP to Weight equation estimates 1/8 mile elapsed time (ET) from vehicle weight and horsepower. This formula provides a theoretical estimation of drag racing performance based on power-to-weight ratio.

2. How Does the Calculator Work?

The calculator uses the HP to Weight equation:

Where:

• \( ET \) — 1/8 mile elapsed time (seconds)
• \( Weight \) — Vehicle weight (pounds)
• \( HP \) — Engine horsepower (hp)

Explanation: The equation demonstrates the cubic relationship between power-to-weight ratio and acceleration performance, where small changes in power or weight can significantly impact quarter-mile times.

3. Importance of ET Calculation

Details: Accurate ET estimation is crucial for drag racing enthusiasts, automotive engineers, and performance tuners to predict vehicle performance, optimize power-to-weight ratios, and set realistic performance goals.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and engine horsepower. Both values must be positive numbers. The calculator provides theoretical ET which may vary from actual performance due to traction, aerodynamics, and drivetrain efficiency.

5. Frequently Asked Questions (FAQ)

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

Q2: What are typical 1/8 mile times?
A: Street cars: 8-12 seconds, Performance cars: 6-8 seconds, Drag cars: 4-6 seconds, Top Fuel: under 4 seconds.

Q3: Does this account for drivetrain loss?
A: No, use wheel horsepower for more accurate results. Engine horsepower typically shows 15-20% higher than wheel horsepower.

Q4: Can I use this for motorcycles?
A: Yes, but motorcycle aerodynamics and traction characteristics differ significantly from cars.

Q5: How does weight reduction affect ET?
A: Reducing weight by 10% typically improves ET by approximately 3%, demonstrating the importance of power-to-weight ratio.