Turbochargers (turbo) have four main parts making up the equipment;  The turbine (radial turbine), impeller/compressor wheels, and the center housing/hub rotating assembly.  The housing of the turbo is fitted around the compressor/impeller and the turbine, it directs gas flow through the wheels as they spin.  

The size and shape of the compressor can determine some performance characteristics of the turbocharger.  This allows the designer of the turbo to tailor the differences between the overall performance, response, and efficiency of the engine system.  Twin-scroll designs have two valve-operated exhaust gas inlets, one is smaller and sharper angled allowing for quick response and the other is larger and less angled for peak performance.

The turbine and impeller wheels of a turbo also determine how much air or exhaust can be passed through the system, depending on the size, and the relative efficiency of their operation.  For the most part, the larger the wheel on the turbine and compressor, the larger amount of gases are able to flow through the turbo.  Size and shape of the wheels can vary, as well as the curvature and the amount of blades present on the wheel will depend on the application of the turbo.

The Center Hub Rotating Assembly (CHRA) houses the shaft of a turbo, which connects the impeller, compressor, and turbine.  It also contains a bearing system, which suspends the shaft and allows it to spin at a very high speed with little friction.  In automotive instances the CHRA generally uses a thrust or ball bearing which is constantly lubricated by pressurized engine oil.  The CHRA  of a turbo could also be "water cooled", which is accomplished by having an area where engine coolant can enter and exit allowing it to cycle.  A water cooled turbo allows the engine coolant to keep lubricating oil cooler, allowing you to avoid possible oil "cooking" which is caused by the extreme heat generated from the turbine in a turbo.

• A turbo contain 4 main parts;  Turbine, Impeller, Compressor, and a Center Housing/Hub Rotating Assembly.
• The turbo compressor can determine some performance characteristics depending on the size and angle of the blades.