Turbochargers are used throughout the automotive in dustry as they can enhance the output of an interna l combustion (IC) engine without the need to increase its cylinder ca pacity. The application of such a mechanical device enables automotive manufacturers to adopt smaller displacement engines,commonly known as �engine downsizing�. Historical ly,turbochargers were often used to increase the potential of an already powerful IC engine. The emphasis today is to provid e a feasible engineering solution to manufacturing economics and �greener� r oad vehicles. It is because of these reasons that t urbochargers are now becoming more and more popular in automobile applic ations. The aim of this paper is to provide a revie w on the techniques used in turbocharging to increase the engine output and reduce the exhaust emission levels. https://www.ijiert.org/paper-details?paper_id=140422