Supercharging is one of the ultimate ways to increase the power output of an engine. By forcing pressurized air into the engine, superchargers substantially raise the volume of air the engine has available for combustion. However, through pressurization, the temperature of the air is substantially increased. The purpose of an intercooler system is to lower the temperature of the supercharged air before it is fed into the engine.
Just as with turbochargers, the function of a supercharger is to compress air as it is fed into the engine. Since pressurized air is much denser than the ambient air, the engine is able to combust a much larger amount of air and fuel during each cycle. This translates into a substantially increased horsepower output. The pressurized air generated by a supercharger is known as "boost" pressure.
Unlike turbochargers, which utilize exhaust gasses to operate, superchargers are belt-driven. Depending on the type of supercharger, an internal turbine or rotor system is used to compress the incoming air and force it into the engine, effectively raising the engine's displacement per revolution. To power the supercharger turbine or rotors, an outer pulley is connected by a belt to the engine crank pulley. When the engine accelerates, the pulley is driven increasingly faster by the crankshaft, causing the supercharger to spool.
As air pressure is increased, temperature also increases. Since hot air is less dense than cold air, feeding the engine with heated air is not ideal, as horsepower and efficiency will suffer. Moreover, in some scenarios, the temperature of the supercharged air is high enough that it causes the air-fuel mixture in the cylinders to prematurely detonate, an effect known as "engine knock." Knocking likewise lowers power output and efficiency, and can lead to reliability issues over time.
To decrease the intake air temperatures, an intercooler is installed between the supercharger outlet and engine throttle body. The intercooler routes the pressurized air from the supercharger through a radiator unit before it is routed into the throttle body. The intercooler's radiator features numerous air pathways interspersed with metal fins. As the vehicle is driven, incoming air passes through the intercooler and keeps the radiator at ambient air temperature. This cools the pressurized air passing through the inside of the intercooler system, maximizing its potential power output.
