Horsepower is a unit of power or the rate at which work will done, usually horsepower is use for the output of automobile engines or motors power. In automobile Horsepower is the power of an engine, that measure power without any other power losses. Horsepower is the power output of an engine that measured at the engine’s flywheel, before transmission and clutches.
Unlike horsepower, the Brake-Horsepower is the power output of any engine that measured at the wheels. (including clutch and transmission) What BHP actually measures, is the maximum rate of acceleration and the top speed of the car.
Horsepower — Other power losses = Brake-Horsepower