1. What is a 1/8-mile HP ET Calculator?

Definition: This calculator estimates a vehicle's horsepower based on its weight and 1/8-mile elapsed time (ET).

Purpose: It helps automotive enthusiasts and racers evaluate engine performance without dyno testing.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( HP \) — Estimated horsepower
• \( W \) — Vehicle weight (pounds)
• \( ET \) — 1/8-mile elapsed time (seconds)

Explanation: The formula relates power-to-weight ratio to acceleration over the 1/8-mile distance.

3. Importance of HP Calculation

Details: Accurate HP estimation helps in tuning vehicles, comparing performance, and predicting quarter-mile times.

4. Using the Calculator

Tips: Enter vehicle weight (including driver) in pounds and 1/8-mile ET in seconds. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why 4.025 in the formula?
A: This is an empirical constant that correlates 1/8-mile performance to horsepower in this calculation method.

Q2: How accurate is this calculation?
A: It provides a reasonable estimate (±5-10%) for most street and drag vehicles under typical conditions.

Q3: Should I use curb weight or race weight?
A: Use the actual weight during the run (including driver, fuel, and any ballast).

Q4: Does this account for traction or aerodynamics?
A: No, it assumes perfect traction and doesn't factor in aerodynamic drag at higher speeds.

Q5: Can I use this for 1/4-mile times?
A: No, use a dedicated 1/4-mile calculator as the relationship isn't linear.