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Power to Weight Ratio Formula:
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Power to Weight Ratio (PWR) is a performance measurement that calculates the amount of horsepower available per unit of weight. It's commonly used in automotive and motorsports to compare vehicle performance capabilities, as it directly relates to acceleration and overall performance potential.
The calculator uses the Power to Weight Ratio formula:
Where:
Explanation: The formula calculates how much horsepower is available to move each pound of vehicle weight. Higher PWR values indicate better acceleration and performance potential.
Details: PWR is crucial for performance evaluation because it directly affects acceleration, hill climbing ability, and overall vehicle dynamics. It provides a more accurate performance comparison than horsepower alone, as it accounts for the vehicle's mass that must be accelerated.
Tips: Enter horsepower in standard horsepower units (hp) and weight in pounds (lbs). Both values must be positive numbers greater than zero for accurate calculation.
Q1: What is a good power to weight ratio?
A: For street cars, 0.06-0.08 hp/lb is good, 0.08-0.10 hp/lb is excellent, and above 0.10 hp/lb is considered high-performance. Race cars often exceed 0.15 hp/lb.
Q2: How does PWR affect acceleration?
A: Higher PWR directly correlates with better acceleration. Doubling the PWR approximately halves the 0-60 mph time, assuming similar traction and gearing.
Q3: Should I use curb weight or gross weight?
A: For performance comparisons, use curb weight (vehicle weight without passengers or cargo). For real-world performance, include typical passenger and cargo weight.
Q4: Can PWR be converted to metric units?
A: Yes, divide kilowatts by kilograms for metric PWR (kW/kg). 1 hp/lb ≈ 1.64 kW/kg.
Q5: Why is PWR more important than total horsepower?
A: PWR accounts for the mass being moved, making it a better performance indicator than horsepower alone. A lighter car with less horsepower can outperform a heavier car with more horsepower if it has a better PWR.