Forced induction is a general term used to describe how air and fuel enter the engine. The two primary systems in use today are superchargers and turbochargers.
TURBOCHARGED ENGINES
The most common form of forced induction today is the turbocharger. A turbocharger is simply a two sided fan. The hot expanding exhaust gas moves through one set if blades which causes the turbine wheel to spin. The other side of the turbine pulls in outside air and forces it into the engine. This fills the cylinders with more air and fuel which in turn produces more power. The turbocharger is very efficient because it’s only power comes from the otherwise wasted exhaust gasses. Turbochargers were mainly used in racing and high performance sports cars until about 2010. In the last few years manufacturers have been using turbochargers in smaller displacement engines in an effort to increase gas mileage while still providing acceptable performance.
FROM MILD TO WILD 
For information on turbocharger kits go here.
SUPERCHARGED ENGINES
A supercharger is a purely mechanical device. A belt that runs around a pulley on the engine crankshaft turns the supercharger.. This uses engine power to spin the supercharger and therefore is not as efficient as the turbocharger. There are two basic types of superchargers. The centrifugal and the roots. They both pull in air, compress it and force it into the engine fuel intake system. The supercharger is mainly used to increase power and is most widely used on larger engines in high performance cars. One of the newest supercharged cars is the Shelby GT 500 Mustang. The GT 500 uses a roots type supercharger on a 5.2 liter V8 engine to produce a whopping 760 horsepower! The Chevrolet Camaro ZL1 and the Dodge Challenger Hellcat also use superchargers to produce similar horsepower numbers.
