1. What is the Quarter Mile HP Formula?

The Quarter Mile HP Formula estimates the horsepower of a vehicle based on its weight and elapsed time (ET) in a quarter mile drag race. This calculation provides a useful approximation of a vehicle's power output.

2. How Does the Calculator Work?

The calculator uses the quarter mile HP formula:

Where:

• \( Weight \) — Vehicle weight in pounds (lbs)
• \( ET \) — Elapsed time in seconds for quarter mile
• 6.29 — Empirical constant derived from drag racing data

Explanation: The formula shows that horsepower increases with the cube of the velocity (represented by the inverse of ET), meaning small improvements in ET require significant power increases.

3. Importance of HP Calculation

Details: Knowing a vehicle's horsepower helps in performance tuning, comparing vehicles, and understanding the power-to-weight ratio which is crucial in drag racing.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and quarter mile elapsed time in seconds. For best results, use actual drag strip times rather than estimates.

5. Frequently Asked Questions (FAQ)

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

Q2: Should I use curb weight or race weight?
A: For most accurate results, use the actual weight of the vehicle as raced (including driver and fuel).

Q3: Does this work for all types of vehicles?
A: It works best for rear-wheel drive cars with good traction. Front-wheel drive or all-wheel drive vehicles may show different results.

Q4: What's a good quarter mile time?
A: Street cars typically run 13-15 seconds, while performance cars can run 10-12 seconds. Professional dragsters run under 7 seconds.

Q5: How can I improve my quarter mile time?
A: Reducing weight, increasing horsepower, improving traction, and optimizing shift points can all help improve ET.