This is achieved by putting more fuel/air mixture into the engine, using a fuel with higher energy content, burning it more rapidly, and getting rid of the waste products more rapidly - this increases volumetric efficiency.

In order to check the amount of the fuel/air mixture, air fuel ratio meters are often used. The weight of this fuel will affect the overall performance of the car, so fuel economy is a competitive advantage. This also means that the performance tuning of an engine should take place in the context of the development of the overall vehicle.