However, the most common use of HP, as a unit, is to measure the power of an engine – which you can determine by hooking it to a dynamometer. What HP actually measures, is the maximum rate of acceleration and the top speed of the car.
On the other hand, Brake Horsepower measures the HP of an engine without considering the loss in power that is caused by some parts of the engine, like the generator, gearbox, water pump and other auxiliary parts.