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ET to HP Formula:
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The ET to HP formula calculates horsepower from elapsed time (ET) and vehicle weight. This formula is commonly used in automotive performance testing to estimate engine power output based on quarter-mile drag strip performance.
The calculator uses the ET to HP formula:
Where:
Explanation: The formula demonstrates the cubic relationship between elapsed time and horsepower, where small improvements in ET result in significant increases in calculated horsepower.
Details: Accurate horsepower estimation is crucial for performance analysis, vehicle tuning, and comparing different vehicle setups. It helps racers and enthusiasts understand the relationship between weight reduction and performance gains.
Tips: Enter vehicle weight in pounds and quarter-mile elapsed time in seconds. Use actual race weights (including driver) and best ET times for most accurate results. All values must be valid (weight > 0, ET > 0).
Q1: How accurate is this formula?
A: This formula provides a good estimate but actual horsepower can vary due to traction, aerodynamics, and drivetrain losses. It's most accurate for rear-wheel drive vehicles with good traction.
Q2: What is a typical ET for different horsepower levels?
A: A 12-second ET typically indicates 300-400 HP, 11-second ET indicates 400-500 HP, and 10-second ET indicates 500-600 HP, depending on vehicle weight.
Q3: Should I use race weight or curb weight?
A: Always use race weight (curb weight + driver + fuel) for most accurate calculations, as this reflects the actual weight during the ET run.
Q4: Why is ET cubed in the formula?
A: The cubic relationship accounts for the exponential increase in power needed to achieve progressively faster elapsed times.
Q5: Can this formula be used for different track conditions?
A: The formula assumes ideal conditions. Adjustments may be needed for altitude, temperature, and track surface conditions that affect performance.