A turbocharger uses an engine’s exhaust gas to drive a turbine wheel at speeds up to 280,000rpm. The turbine wheel is connected by a shaft to a compressor wheel and the two wheels turn together to suck in and compress large amounts of ambient air. This air is very dense and very hot, so it is passes through a charge-air cooler, where it cools and gains even higher density before entering the engine. The presence of this compressed air makes the fuel burn more efficiently, thereby delivering greater power while consuming less energy.
Increasingly, turbos are coupled with high pressure fuel injection systems, a combination that makes for even more thorough, efficient and cleaner combustion.