ET Calculator 1/8 Mile

1/8-Mile Elapsed Time Formula:

\[ ET = \left(\frac{W}{HP}\right)^{\frac{1}{3}} \times 4.025 \]

1/8-Mile Elapsed Time (s):

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1. What is a 1/8-Mile ET Calculator?

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

Purpose: It helps racers and performance enthusiasts predict quarter-mile performance without actual track testing.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ ET = \left(\frac{W}{HP}\right)^{\frac{1}{3}} \times 4.025 \]

Where:

\( ET \) — Elapsed time (seconds)
\( W \) — Vehicle weight (pounds)
\( HP \) — Engine horsepower

Explanation: The formula calculates the theoretical best possible ET based on power-to-weight ratio, with 4.025 being an empirical constant for 1/8-mile distance.

3. Importance of ET Calculation

Details: ET estimation helps in tuning decisions, comparing vehicle setups, and setting realistic performance expectations.

4. Using the Calculator

Tips: Enter the vehicle weight in pounds (including driver) and the engine's horsepower. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: This provides a theoretical best time. Actual times will vary based on traction, aerodynamics, and launch technique.

Q2: Should I use wheel horsepower or engine horsepower?
A: For most accuracy, use wheel horsepower (measured at the wheels on a dyno).

Q3: Does this include driver weight?
A: The weight should include the vehicle plus driver and any significant cargo.

Q4: Can I calculate 1/4-mile time from this?
A: Multiply the 1/8-mile ET by approximately 1.56 to estimate 1/4-mile time.

Q5: Why the cube root in the formula?
A: The cube root accounts for the non-linear relationship between power-to-weight ratio and acceleration.