1. What is Rear Wheel to Crank Horsepower Conversion?

Definition: This calculator estimates engine (crank) horsepower based on measured wheel horsepower and drivetrain loss factor.

Purpose: It helps automotive enthusiasts and professionals estimate engine power from dyno measurements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( CHP \) — Crank Horsepower (engine output)
• \( WHP \) — Wheel Horsepower (measured at wheels)
• \( DTL \) — Drivetrain Loss Factor (typically 0.10-0.20)

Explanation: The formula accounts for power lost through the drivetrain (transmission, differential, etc.) between the engine and wheels.

3. Importance of Accurate Conversion

Details: Understanding true engine power helps in performance tuning, vehicle comparisons, and meeting racing class requirements.

4. Using the Calculator

Tips: Enter measured wheel horsepower and drivetrain loss factor (default 0.15 for RWD cars). DTL must be between 0 and 0.5.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical drivetrain loss factor?
A: Typically 15% for RWD (0.15), 20% for AWD (0.20), and 10% for FWD (0.10) vehicles.

Q2: Why measure WHP instead of CHP directly?
A: WHP represents actual power reaching the wheels, which is what moves the vehicle.

Q3: Does this work for electric vehicles?
A: EV drivetrain losses are typically lower (5-10%) due to fewer mechanical components.

Q4: How accurate is this estimation?
A: It's an approximation - actual losses vary by vehicle condition, temperature, and dyno type.

Q5: Where can I measure WHP?
A: At performance shops with dynamometer (dyno) testing equipment.