Since the invention of the internal combustion engine, automotive engineers, speed junkies and racecar designers have been searching for ways to boost its power. One way to add power is to build a bigger engine. But bigger engines, which weigh more and cost more to build and maintain, are not always better. Another way to add power is to make a normal-sized engine more efficient. Adding either a turbocharger or a supercharger is a great way to achieve forced air induction. Both superchargers and turbochargers pressurize the air intake to above atmospheric pressure. The difference between the two devices is their source of energy. Turbocharger is an exhaust gas driven compressor used in internal-combustion engines to increase the power output of the engine by increasing the mass of oxygen entering the engine. A key advantage of turbochargers is that they offer a considerable increase in engine power with only a slight increase in weight.Unlike turbochargers, which use the exhaust gases created by combustion to power the compressor, superchargers draw their power directly from the crankshaft. Superchargers increase intake by compressing air above atmospheric pressure, without creating a vacuum. This forces more air into the engine, providing a "boost." With the additional air in the boost, more fuel can be added to the charge, and the power of the engine is increased. There are three types of superchargers: roots, centrifugal, twin-screw. The main difference among them is how they move air to the intake manifold of the engine. Roots and twin-screw superchargers use different types of meshing lobes, and a centrifugal supercharger uses an impeller, which draws air in. Although all of these designs provide a boost, they differ considerably in their efficiency and sizes. The biggest advantage of having a supercharger is the increased horsepower.
