Correction: they're turbocharged not supercharged. For those that don't know the difference, a turbocharger is two turbines connected to eachother. One, powered by exhaust gases, spins the other, which forces air into the combustion chamber (the pressure applied is typically called "boost"). More air means more fuel can be injected while maintaining stoichiometric equilibrium. More fuel combusted means more power is produced, given equal waste due to friction etc.
A supercharger is very similar, but conceptually more simple. The turbine creating boost is instead connected mechanically to the engine's crankshaft, being driven directly by the engine.
A supercharger is very similar, but conceptually more simple. The turbine creating boost is instead connected mechanically to the engine's crankshaft, being driven directly by the engine.