Wheel Horsepower (WHP)

Losses come from the gearbox, differential, driveshafts and tyres. Manufacturers quote engine power measured at the crankshaft. The gap between the two figures varies with the drivetrain type. All-wheel-drive cars usually lose more power through the drivetrain than two-wheel-drive cars.

Friction and heat in the drivetrain consume part of the engine’s output before it reaches the road.

Do not compare a wheel figure directly with a manufacturer’s crank figure. Correction factors used to “convert” wheel power to crank power are only estimates.