Turbo systems use the exhaust gases coming out of the engine to drive a turbine, which powers a compressor, which in turn feeds this compressed air into the engine.

Turbo chargers are very efficient in that they require no loss of engine power to charge the compressed air that goes into the engine.
A turbine is, essentially, a windmill. Exhaust gasses coming out of the engine exhaust manifold blow across the fan blades, causing them to spin. This exhaust gas hits the blades at two different angles, which is very efficient , almost all of the energy from the exhaust is used and very little is wasted. The force created from the turbine spins the compressor fan because they share the same shaft.



The compressor's fan blades spin faster and faster as the shaft is turned quicker, and this compresses the air. The compressing of the air inside of the compressor housing effectively multiplies the air. This high volume of air rushes forcefully out of the housing to make way for more compressed air.
When air volume increases, the density of the air decreases. More compressed air occupies the same amount of space, increasing the volume, but this creates a by-product of heat, which effectively decreases the density of the same air. This is where your high school chemistry comes in handy.

Remember the equation of ( MASS = DENISTY x VOLUME )?
The goal is to create more air, (MASS) not just volume.
The higher the density, the lower the volume, due to the heat factor.

The mass of air forced into the engine only becomes beneficial when the volume of air is higher than the decrease in density.

In order to counter the heat factor, you must find a way of cooling the air, which increases the density. This is accomplished with the use of an intercooler.
Intercoolers are somewhat like a radiator without water, traditionally sitting in the front nose of the car without any obstructions blocking the cooling fins. The compressed air from the turbo charger is plumbed into the intercooler, and the outside air rushing through the cooling fins lowers the ambient temperature of the charged air.



With the installation of an intercooler, the volume of compressed air will be reduced; however, the better quality (cooler, more dense) air more than makes up for the loss in pressure. In fact, most efficient turbo chargers produce too much boost (compressed air), and this has to be released out into the atmosphere. Some manufactures are beginning to market liquid cooled intercoolers which have benefits of better cooling, reduced loss of charged air, and saving space in the engine compartment.
Boosting the intake air into the engine requires careful management of the levels of pressure and timing. To prevent adding too much boost into the system, waste gates are employed. A waste gate attaches to the exhaust manifold and acts like a valve, regulating the boost pressure and keeping boost levels constant. Also, blowoff valves are employed just before the intake manifold to relieve the pressure in the system between shifts when the rotation of the engine is winding down. This keeps pressure from moving backwards toward the turbo.

Keep in mind that the combination of both fuel and air create the explosion that produces power. With the addition of more air into the engine, a corresponding amount of fuel must also be added to the mix. Also, lowering the compression in the combustion chamber is needed to keep the engine durable. With higher compression in the engine, detonation can occur from the pressure alone. Detonation is the exploding of the fuel-air mixture before the engine is ready for it to happen. The piston is still moving upward when the combustion process happens, and this leads to broken rods, cracked piston tops, blown head gaskets, etc.

Turbo chargers are very efficient in helping
to producing large amounts of horsepower,
canceling the worn out adage of
" No replacement for displacement ".

Now on to a detailed view of specific Turbocharger
parts.