1. What is a Crank HP vs Wheel HP Calculator?

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

Purpose: It helps automotive enthusiasts and professionals understand the relationship between engine output and actual power delivered to the wheels.

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 0.10-0.25)

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

3. Importance of Crank HP Calculation

Details: Understanding drivetrain loss helps in vehicle performance analysis, tuning, and comparing dyno results across different vehicles.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's a typical drivetrain loss factor?
A: Typically 10-15% for RWD (0.10-0.15), 15-20% for FWD (0.15-0.20), and 20-25% for AWD (0.20-0.25) vehicles.

Q2: Why is WHP lower than CHP?
A: Power is lost through friction in the transmission, differential, and other drivetrain components before reaching the wheels.

Q3: How accurate is this calculation?
A: It provides a good estimate, but actual drivetrain loss can vary based on vehicle condition, temperature, and other factors.

Q4: Can I use this for electric vehicles?
A: EV drivetrain losses are typically much lower (5-10%) due to simpler drivetrains.

Q5: Where can I measure WHP?
A: Wheel horsepower is measured on a dynamometer (dyno) at automotive performance shops.