Forced induction makes an engine burn more fuel than it would have been possible if induction was driven at atmospheric pressure, i.e., an engine without forced induction is considered to be naturally aspirated engines.It uses a gas compressor to increase the density of the air, temperature and the pressure. To increase engine power and efficiency, Forced induction is used in the automotive and aviation industry. A forced induction engine is essentially made up of two compressors in series. The compression stroke of the engine is the main compression that every engine has and an additional compressor feeding into the intake of the engine makes it a forced induction. A compressor feeding pressure into another is used to increase the total compression ratio of the entire system by a large factor and this intake pressure is called boost. This greatly helps aviation engines as they operate at high altitudes. One of the side – effects of Forced induction is that compressing air raises its temperature and this is unavoidable and follows first law of thermodynamics. Consequently, the charge density is reduced and cylinders are reduced and the cylinders receive air which is less in comparison system’s boost pressure prescribes, thereby, increasing the risk of detonation, or "knock". These effects are counteracted by intercoolers. Water injection is one of the effective means of cooling the charged air to prevent explosion. Diesel engines don’t have any sort of pre – ignition problems as the fuel is injected at the end of the compression stroke, therefore higher compression is used. Most modern diesel engines use a turbocharger because the exhaust from a diesel is very strong making it excellent for powering a turbo.