1. What is Crank to Wheel Horsepower?

Crank to Wheel Horsepower calculation converts engine horsepower (measured at the crankshaft) to wheel horsepower (measured at the wheels), accounting for drivetrain losses through the transmission, differential, and other components.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• \( \text{Crank HP} \) — Engine horsepower measured at the crankshaft
• \( \text{Drivetrain Loss \%} \) — Percentage of power lost through the drivetrain
• \( \text{Wheel HP} \) — Horsepower actually delivered to the wheels

Explanation: The formula accounts for mechanical losses in the transmission, driveshaft, differential, and other drivetrain components that reduce the power reaching the wheels.

3. Importance of Horsepower Calculation

Details: Understanding the difference between crank and wheel horsepower is crucial for vehicle performance tuning, dyno testing, and accurate performance comparisons between different vehicles and modifications.

4. Using the Calculator

Tips: Enter crank horsepower in hp and drivetrain loss percentage (typically 10-20% for most vehicles). All values must be valid (crank HP > 0, loss % between 0-50).

5. Frequently Asked Questions (FAQ)

Q1: What is typical drivetrain loss percentage?
A: Most vehicles lose 10-20% of power through the drivetrain, with front-wheel drive typically having lower losses than rear-wheel drive, and all-wheel drive having the highest losses.

Q2: Why is wheel horsepower lower than crank horsepower?
A: Power is lost through friction in the transmission, driveshaft, differential, wheel bearings, and other mechanical components between the engine and wheels.

Q3: How is drivetrain loss measured?
A: Drivetrain loss is typically calculated by comparing engine dyno results (crank HP) with chassis dyno results (wheel HP) on the same vehicle.

Q4: Does drivetrain loss vary by vehicle type?
A: Yes, factors like transmission type (manual vs automatic), drive configuration (FWD, RWD, AWD), and vehicle age/condition all affect drivetrain loss percentages.

Q5: Can drivetrain loss be reduced?
A: Yes, through modifications like lightweight driveshafts, performance transmission fluids, upgraded differentials, and reduced rotating mass components.