Parts of a Turbo – Labeled Turbocharger Diagram

All 13 parts on the diagram

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Cut through along the shaft 9

Compressor housing Fresh air comes in through its middle. The wheel flings the air outward into the scroll round the rim, which shows here as a round passage above and below.
Compressor wheel Spins with the turbine wheel. It draws air in at its center and throws it out at its rim. It is also called the impeller.
Shaft The turbine wheel drives it, and it drives the compressor wheel. That makes both turn at the same speed.
Center housing Holds the shaft and its bearings. The oil passages are in it. One maker calls it the bearing housing.
Journal bearings They float on a film of oil. That is why the turbocharger needs a steady supply of clean oil from the engine.
Oil inlet Oil from the engine comes in here under pressure. It runs down to the bearings.
Oil outlet Oil that has passed through the bearings runs out here. It runs back to the engine. It is also called the oil drain.
Turbine wheel Hot exhaust gas is aimed at it and spins it. It is the part that turns the shaft.
Turbine housing Exhaust gas from the engine runs around its scroll. Then in through the turbine wheel and out through the middle.

The outside 4

Compressor outlet (discharge) Compressed air goes out here on its way to the engine's intake.
Turbine inlet Bolts to the exhaust manifold. The exhaust gas comes in through it.
Wastegate When it opens, some exhaust gas goes past the turbine, not through. That keeps the pressure of the air going to the engine from rising too far.
Wastegate actuator A diaphragm inside feels the pressure from the compressor. When that pressure reaches its limit, the rod pushes the wastegate open.

How this list was compiled: Part names checked on 2026-09-30; a name is kept only when two independent sources use it. (1) US Army TM 9-8000, Principles of Automotive Vehicles, 1985, paragraph 4-30 and figure 4-67, https://archive.org/details/tm-9-8000-principles-of-automotive-vehicles-1985 (turbine wheel, turbine housing, compressor wheel, compressor housing, turbine shaft, waste gate and its diaphragm, exhaust manifold). (2) A car maker's training booklet on basic turbochargers, https://archive.org/details/ford-basic-turbochargers (turbine wheel, turbine housing, compressor or impeller wheel, compressor housing, center housing, shaft, bearings, oil inlet passage, oil outlet port, wastegate, wastegate actuator and rod, compressor outlet and compressor discharge, turbine inlet). (3) A turbocharger maker's service manual, https://archive.org/details/manualzilla-id-6031201 (bearing housing, turbine housing, turbine wheel, compressor wheel, compressor housing, journal bearing, thrust bearing, oil inlet, oil outlet, actuator, turbine inlet and outlet). (4) A primer on another maker's turbochargers, https://archive.org/details/manualzilla-id-6024726 (turbine wheel, turbine housing, compressor wheel, compressor housing, center housing, journal bearings, wastegate valve worked by a diaphragm, turbine inlet). (5) Wikipedia, Turbocharger and Wastegate, text only (turbine, compressor, center housing rotating assembly, shaft, bearing, wastegate, wastegate actuator, internal wastegate flap, compressor discharge). Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's turbocharger, nothing traced. Licence: own work

How it works

The parts of a turbocharger are two wheels on one shaft. Exhaust gas spins the turbine wheel, and the compressor wheel on the other end packs more air into the engine.

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Cut through: two wheels, one shaft

The turbine housing and turbine wheel are on the right, where the exhaust goes through. The compressor housing and compressor wheel are on the left, where fresh air goes through. The center housing between them holds the shaft in two journal bearings, with an oil inlet on top and an oil outlet underneath.

Outside: what controls it

Seen from the turbine end, the wastegate is the flap beside the turbine wheel. The wastegate actuator is the can whose rod opens it. The turbine inlet is the bolted flange, and the compressor outlet is the pipe behind.

The two sides never share gas. Exhaust stays in the turbine housing and fresh air in the compressor housing.
The Army's manual spells it waste gate. Most other sources write wastegate.

Questions and answers

What are the main parts of a turbo?

A turbine wheel in a turbine housing, a compressor wheel in a compressor housing, the shaft that joins the two wheels, and a center housing with the bearings and oil passages. Most also have a wastegate and an actuator.

What is the difference between the turbine and the compressor?

The turbine is the driving side: exhaust gas spins its wheel. The compressor is the driven side: its wheel is turned by the shaft, draws fresh air in and forces it toward the engine.

What does the wastegate on a turbo do?

It is a valve that lets some exhaust gas go round the turbine wheel. That holds the turbine's speed down, which limits the pressure of the air the compressor sends to the engine.

Why does a turbocharger need oil?

Its shaft turns very fast in journal bearings that ride on a film of oil. Clean oil from the engine comes in at the oil inlet and drains back to the engine from the oil outlet.