1. What is the Motorsports Power Formula?

Definition: This calculator estimates the horsepower of a vehicle based on its weight and 1/4-mile elapsed time (ET).

Purpose: It helps motorsports enthusiasts and engineers evaluate vehicle performance without dyno testing.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The formula relates power-to-weight ratio with acceleration over a standard distance, where 5.825 is an empirical constant.

3. Importance of Power Calculation

Details: Accurate power estimation helps in vehicle tuning, performance comparison, and verifying claimed horsepower figures.

4. Using the Calculator

Tips: Enter the vehicle weight in pounds (including driver) and the 1/4-mile elapsed time in seconds. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this formula?
A: It provides a good estimate (±5-10%) for most rear-wheel-drive vehicles with good traction.

Q2: Why is weight important in the calculation?
A: Power-to-weight ratio directly affects acceleration - heavier vehicles need more power for the same ET.

Q3: Does this work for all vehicle types?
A: Best for rear-wheel-drive cars. Front-wheel-drive and AWD may show different results due to drivetrain losses.

Q4: What's a good ET for a street car?
A: 13-15 seconds is typical for performance cars, while 8-10 seconds is race car territory.

Q5: How can I improve my ET?
A: Reduce weight, increase power, improve traction, or optimize shift points and launch technique.