Internal combustion engines are "breathing" engines. That is to say, they draw in air and fuel for energy. This energy is realized as power when the air-fuel mixture is ignited. Afterward, the waste created by the combustion is expelled. All of this is typically accomplished in four strokes of the pistons. What a turbocharger does is to make the air-fuel mixture more combustible by fitting more air into the engine's chambers which, in turn, creates more power and torque when the piston is forced downward by the resulting explosion. It accomplishes this task by condensing, or compressing, the air molecules so that the air the engine draws in is denser. Now, how it does that is the real story here.
A turbocharger is a way to force air into the engine. Hot exhaust gas powers the turbine wheel of the supercharger to make it rotate. That turbine wheel is connected by a shaft to a compressor wheel. As the turbine wheel spins faster and faster, it causes the compressor wheel to also spin quickly. The rotation of the compressor wheel pulls in ambient air and compresses it before pumping it into the engine's chambers. As you may have guessed, the compressed air leaving the compressor wheel housing is very hot as a result of both compression and friction. That's where a charge-air cooler (or "intercooler") comes in. It reduces the temperature of the compressed air so that it is denser when it enters the chamber. The intercooler also helps to keep the temperature down in the combustion chamber. All together, the engine, turbocharger and charge-air cooler form what is known as a "charge-air system". Some systems also include a tip turbine fan which draws air across the charge-air cooler to further reduce the temperature of the compressed air generated by the turbocharger.
The basic principal behind turbocharging is fairly simple, but a turbocharger very complex. Not only must the components within the turbocharger itself be precisely coordinated, but the turbocharger and the engine itself must also be exactly matched. If they're not, engine inefficiency and even damage can be the results. That's why it's important to follow correct installation, operating and preventative maintenance procedures.
When adding a turbo kit or other forced induction system to an engine, you need to pay close attention to the air/fuel mixture ratio, as running lean can cause damaging detonation. Also pay attention to how much air the heads can efficiently flow. This is more difficult to measure or calculate, but much like the diameter of a straw can effect how much liquid it can draw, the heads will limit how much air they can flow through the system. We will cover this in depth in future post.
Stay tuned for more in depth analysis on turbocharging systems. For great turbo kits, check out our wide selection of auto parts and accessories at Majestic Modifications Online.
