Wallace 1/4 Mile Calculator

Wallace Formula:

\[ ET = 5.825 \times \left(\frac{Weight}{HP}\right)^{0.333} \]

Elapsed Time (ET):

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1. What is the Wallace 1/4 Mile Formula?

The Wallace 1/4 Mile Formula is an empirical equation used to estimate the elapsed time (ET) for a vehicle to complete a quarter-mile drag race based on its weight and horsepower. It provides a quick and reasonably accurate prediction of drag racing performance.

2. How Does the Calculator Work?

The calculator uses the Wallace formula:

\[ ET = 5.825 \times \left(\frac{Weight}{HP}\right)^{0.333} \]

Where:

\( ET \) — Elapsed Time (seconds)
\( Weight \) — Vehicle weight (pounds)
\( HP \) — Engine horsepower (horsepower)
\( 5.825 \) — Empirical constant
\( 0.333 \) — Exponent (cube root)

Explanation: The formula calculates the cube root of the weight-to-power ratio and multiplies it by the empirical constant to estimate quarter-mile performance.

3. Importance of ET Calculation

Details: Quarter-mile elapsed time is a standard performance metric in drag racing. Accurate ET estimation helps racers understand their vehicle's potential, compare different setups, and make informed decisions about modifications.

4. Using the Calculator

Tips: Enter vehicle weight in pounds and engine horsepower. Use curb weight (vehicle + driver + fuel) for most accurate results. All values must be valid (weight > 0, horsepower > 0).

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the Wallace formula?
A: The Wallace formula provides a good estimate for most street-legal vehicles but may be less accurate for highly modified race cars or vehicles with exceptional traction characteristics.

Q2: What factors affect quarter-mile times besides weight and horsepower?
A: Traction, aerodynamics, transmission type, tire compound, suspension setup, and driver skill all significantly impact actual quarter-mile performance.

Q3: Should I use flywheel or wheel horsepower?
A: For most accurate results, use flywheel horsepower (engine horsepower). If using wheel horsepower, remember that drivetrain losses typically range from 15-20%.

Q4: What is considered a good quarter-mile time?
A: For street cars, 13-14 seconds is respectable, 11-12 seconds is very fast, and sub-10 seconds is professional racing territory. Times vary greatly by vehicle type and class.

Q5: Can this formula predict trap speed?
A: No, the Wallace formula only estimates elapsed time. Trap speed (speed at the finish line) requires additional calculations and depends on acceleration curve characteristics.