Specific Power

the ratio of an engine’s power to its weight or other parameter. In Soviet usage, the power of a piston engine referred to the engine’s displacement is called the power per liter of displacement; when the power is referred to the total piston area, it is known as the piston power, and so on. For example, the power per liter of displacement of carburetor automotive engines is 30–45 kilowatts per liter (kW/7), and for diesel engines without supercharging it is 10–15 kW/7. The specific power can be increased by the use of light alloys, by improvements in design, and by forcing (increasing the rate of rotation and the compression ratio, using supercharging, and so on).