Converting Kilowatts (kW) into Horsepower (HP)
Example: How much horsepower (HP) does a VW Golf 1.4 with 55 kW?
Conversion: 55 kW X 1.36 = 74.8 HP
In the past, engines (mainly steam engines) were compared with the strength of a draft horse, which generates circa 750 watts. In engineering, this unit of measurement was maintained. Horsepower was denoted in technical formulas by the letter N.
The kW or HP-number of an engine depends on various mechanical parameters. First and foremost, the size of the working pressure is crucial; also the size of the cubic capacity, the cylinder charging, the degree of compression, the ignition setting and the opening and closing times of the valves.
More important than the number of kilowatts or horsepower is the work that affects the motor in the form of torsional force (torque). For the acceleration and hill climbing ability of a car, the torque of its engine is key, which decreases with increasing number of revolutions.
Nowadays it is possible to increase the horsepower of the vehicle by so-called "chip tuning". This is technically simple to perform, but may bring problems with the registration.