Dyno Calculator

Calculate horsepower, torque, and drivetrain losses. Convert between wheel HP and crank HP for RWD, FWD, and AWD vehicles.

HP to Torque: Torque = (HP x 5252) / RPM Torque to HP: HP = (Torque x RPM) / 5252 Wheel to Crank: Crank HP = Wheel HP / (1 - Loss%) Drivetrain Losses: - RWD Auto: 15% - FWD Auto: 12% - AWD: 20% - RWD Manual: 13% - FWD Manual: 10%
Example: 200 HP at 5000 RPM (RWD Auto) Torque = (200 x 5252) / 5000 = 210 lb-ft Crank HP = 200 / 0.85 = 235 HP HP Lost = 235 - 200 = 35 HP

What is the difference between wheel HP and crank HP?

Wheel horsepower (WHP) is the power measured at the wheels on a dyno, while crank horsepower is the power at the engine's crankshaft. The difference is drivetrain loss - power lost through transmission, driveshaft, differential, and axles. RWD cars lose about 15%, FWD 12%, and AWD 20%.

How do you calculate torque from horsepower?

Torque = (Horsepower × 5252) / RPM. The constant 5252 comes from converting rotational motion to linear force. At 5252 RPM, horsepower and torque values are numerically equal.

Why is AWD drivetrain loss higher?

AWD systems lose more power (about 20%) because power travels through additional components: transfer case, front differential, front axles, and potentially viscous couplings. Each component adds friction and parasitic loss.

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