1. What is the Horsepower ET Formula?

The Horsepower ET (Elapsed Time) formula estimates a vehicle's horsepower based on its weight and quarter-mile elapsed time. It's commonly used in drag racing to evaluate performance.

2. How Does the Calculator Work?

The calculator uses the horsepower formula:

Where:

• \( Weight \) — Vehicle weight in pounds (lbs)
• \( ET \) — Quarter-mile elapsed time in seconds
• 5.825 — Empirical constant for the formula

Explanation: The formula shows that horsepower is proportional to weight and inversely proportional to the cube of elapsed time.

3. Importance of Horsepower Calculation

Details: Accurate horsepower estimation helps in vehicle performance analysis, tuning, and comparing different vehicles' potential performance.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and quarter-mile elapsed time in seconds. All values must be valid (weight > 0, ET > 0).

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this formula?
A: It provides a reasonable estimate but actual horsepower may vary due to traction, aerodynamics, and other factors.

Q2: What's a good quarter-mile time?
A: For street cars, 12-14 seconds is good. Professional drag cars can run under 7 seconds.

Q3: Does this work for all vehicle types?
A: It works best for rear-wheel drive vehicles. Front-wheel drive and all-wheel drive may have different results due to drivetrain losses.

Q4: Should I use curb weight or race weight?
A: For most accurate results, use the actual weight during the run (including driver and fuel).

Q5: Can I use this for 1/8 mile times?
A: No, this formula is specifically designed for quarter-mile times. Different formulas exist for 1/8 mile calculations.