Internal combustion engine
For extra power, more air is needed to increase the energy evolved per unit of fuel. This is where forced induction must take place. There are some ways of creating forced induction such as turbochargers and superchargers. Turbochargers rely on the volume and velocity of the exhaust to spin the turbine wheel in the middle of the turbocharger. Turbochargers should consume less power from the engine than superchargers and therefore suffer bad throttle response. This delay can also be referred to as turbo lag. Smaller turbochargers spool quickly and deliver more boost pressure at lower engine speeds but suffers at higher RPMs. On the contrary, bigger turbochargers can deliver more power at higher revs but suffers low throttle response. There can be many turbochargers in a car, but the most common amount being 1 and 2. Superchargers on the other hand, have close to no lag time as the compressor is constantly spinning proportionally to the engine speed. However, they require torque from the engine to operate. Some common types of superchargers are the Roots-type supercharger, a Screw-type supercharger, and a Centrifugal-type supercharger. In a Roots-type supercharger there are paddles on two drums that are continuously rotating, that forces air into the intake. The Roots-type supercharger is a positive displacement device and therefore has the advantage of producing the same pressure ratio at any engine speed. A Screw-type supercharger, like the Roots-type supercharger, is a positive displacement device. They consist of 2 screws that compresses the air and are more efficient than roots type as they create a cooler air output than a roots supercharger but are more difficult to manufacture. A centrifugal-type supercharger, is not a positive displacement device. Although it looks like a turbocharger, they are very different as the power source of the centrifugal supercharger is horsepower from the engines crankshaft whereas a turbocharger uses the exhaust gas to spin the compressor.