1. What is Rear Wheel Horsepower to Engine Horsepower Calculator?

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 output 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 0.15-0.2)

Explanation: The formula accounts for power lost through the drivetrain (transmission, differential, etc.) to estimate original engine output.

3. Importance of Accurate Power Calculation

Details: Understanding true engine power helps in vehicle tuning, performance comparisons, and diagnosing mechanical issues.

4. Using the Calculator

Tips: Enter measured wheel horsepower and drivetrain loss factor (default 0.15). Typical DTL values range from 0.15 (15%) for RWD to 0.20 (20%) for AWD.

5. Frequently Asked Questions (FAQ)

Q1: Why is WHP different from engine horsepower?
A: Power is lost through the drivetrain components (transmission, driveshaft, differential, etc.) before reaching the wheels.

Q2: What's a typical drivetrain loss percentage?
A: Typically 15-20%: ~15% for RWD, ~18% for FWD, and ~20% for AWD vehicles.

Q3: Can drivetrain loss vary?
A: Yes, based on drivetrain type, condition, lubrication, and modifications. Older vehicles may have higher losses.

Q4: Is this calculation exact?
A: It's an estimate. Actual losses can vary based on many factors including temperature, load, and drivetrain condition.

Q5: How do I measure wheel horsepower?
A: WHP is measured on a dynamometer (dyno) which measures power at the wheels under controlled conditions.