1. What is a Horsepower to Speed Calculator?

Definition: This calculator estimates a vehicle's quarter-mile trap speed based on its horsepower and weight.

Purpose: It helps automotive enthusiasts and professionals estimate performance without track testing.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( MPH \) — Quarter-mile trap speed (miles per hour)
• \( HP \) — Engine horsepower
• \( W \) — Vehicle weight (pounds)

Explanation: The cube root of the power-to-weight ratio is multiplied by an empirical constant (234) to estimate speed.

3. Importance of Power-to-Weight Ratio

Details: This ratio is critical in vehicle performance. Higher ratios mean better acceleration and higher top speeds.

4. Using the Calculator

Tips: Enter the vehicle's horsepower and weight in pounds. Both values must be > 0 for calculation.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It provides a rough estimate. Actual performance depends on traction, gearing, aerodynamics, and drivetrain losses.

Q2: Does this include driver weight?
A: No, add driver and passenger weight to the vehicle weight for more accurate results.

Q3: What's a good quarter-mile speed?
A: Street cars typically run 13-16 seconds (90-110 mph), while performance cars can exceed 120+ mph.

Q4: Can I use this for motorcycles?
A: Yes, but motorcycles often have better power-to-weight ratios than their quarter-mile times suggest due to traction limits.

Q5: Why the cube root relationship?
A: Aerodynamic drag increases with the square of speed, while power needed increases with the cube of speed.