We all know that most diesel trucks these days already come equipped with a turbo or sequential turbo setup from the factory and that means more power for your truck. But what most truck owners know little about is what makes up a turbo and how it works. Well, thanks to the folks at BorgWarner Turbo and Emissions Systems, we were able to get a breakdown of each part and what it does.

What's A Turbo Made Of?
There are many parts that work together in tandem to create the boost pressure that makes the turbo provide the horsepower and torque that you want and need. We will walk you through the basics and explain to you how each part aids in this process, starting with the turbine housing.

Turbine Housing
The turbine (Exhaust) housing is not only where the exhaust gases enter the turbo set up, but it directs the exhaust gases from the exhaust manifold around the turbine wheel and out. Included in this housing are:
 
Shaft
The shaft is the main connecting rod that holds and spins the turbine and compressor wheels. The turbine wheel is friction-welded to the shaft for maximum performance and durability. The compressor wheel slides onto the shaft and a nut holds it in place.

Turbine wheel
The turbine wheel above is basically what makes the whole turbo work.  As the exhaust gasses expand in the turbine housing, the turbine spins faster, causing the compressor wheel to spin faster, thus creating boost on the intake side.

Bearing Housing
The bearing housing is where the entire rotating assembly (cartridge or core assembly) is housed. It is, also, responsible for receiving the turbo's oil supply and draining it, as well as what the turbine and the compressor housings bolt to. Included in the bearing housing is the:

Journal Bearing
The journal bearing keeps the shaft centered and turning smoothly. There are two  of these located on the shaft with a spacer between.  

Spacer
The spacer keeps the two bearings in place.

Flinger and Insert Assembly
The flinger and insert assembly keeps the oil from being sucked through and into the intake. It also keeps the boost pressure from leaking into the bearing housing and/or onto the crankcase.

Thrust Bearing
The thrust bearing is responsible for carrying the axial load (the load under the acceleration of the wheels) under all conditions.

Snap ring
The snap ring seats the thrust parts assembly and this in turn, positions the entire rotor in the bearing housing.
On the other side of the turbo set up, you have the compressor side and all the components that it is made up of. This is the final stage in the spooling up of the turbo and where the boost gets distributed to your engine.
Compressor Housing
The compressor housing is the inlet housing that directs the intake air around the compressor wheel and out. Inside this housing you have:

Compressor Wheel
The compressor wheel is on the inlet side (where the air enters the turbo) and compresses the inlet air, which creates the boost pressure. This is also the most commonly upgraded part. (I.E., moving to a larger diameter wheel to add additional power and boost.)

Nut
This nut is what holds the compressor wheel on the shaft.