What is a Turbocharger and How Does it Work?


A constant goal in the area of engines with internal combustion is to maximize power production and efficiency. The turbocharger represents a technological advancement that has completely changed how engines work as a result of this pursuit. This page digs further into the operation of turbochargers, examining their types, benefits, drawbacks, and even the background of their development.A turbocharger significantly improves your engine performance by increasing air intake, resulting in enhanced combustion and power output. This technology boosts efficiency and allows for higher horsepower without increasing engine size, ideal for maximizing vehicle performance.

How Does It Work?

The turbine and the compressor are the two fundamental components of a turbocharger. A common shaft links these parts together. The turbine spins due to the exhaust gases from the engine passing through the turbine housing. The compressor wheel, which is situated in the direction of the intake air, receives this rotating motion through the shaft. Prior to delivering the compressed air to the engine’s intake manifold, the compressor wheel pulls in ambient air. The engine can burn more gasoline thanks to this compressed air, increasing power output.

Types of Turbochargers:

Single Turbocharger: 

This kind, which has a single turbine and compressor, is the most prevalent.

Twin Turbocharger: 

Two turbochargers of different sizes work together in this setup to provide improved power distribution at various engine speeds.

Variable Geometry Turbocharger (VGT):

VGTs optimize performance for a range of engine loads by controlling the flow of exhaust gases onto the turbine using movable vanes.

Twin-Scroll Turbocharger: 

This design decreases turbo lag and increases efficiency by routing exhaust gases through independent scrolls on the turbine housing.

Who Invented the Turbocharger?

Early in the 20th century, using exhaust fumes to power a compressor was first proposed. The turbocharger was created in 1905 and is widely credited to Swiss engineer Alfred Buchi. His groundbreaking innovation served as the basis for today’s sophisticated turbochargers.


Like other forced induction devices, a compressor in the turbocharger pressurizes the intake air before it enters the inlet manifold. In the case of a turbocharger, the compressor is powered by the kinetic energy of the engine’s exhaust gases, which is extracted by the turbocharger’s turbine.

The main components of the turbocharger are:

  • Turbine: usually a radial turbine design
  • Compressor: usually a centrifugal compressor
  • Center housing hub rotating assembly


The turbine section of a Garrett GT30 with the cover removed

The turbine section (also called the “hot side” or “exhaust side” of the turbo) is where the rotational force is produced in order to power the compressor (via a rotating shaft through the center of the turbo). After the exhaust has spun the turbine, it continues into the exhaust and out of the vehicle.

The turbine transforms the mechanical energy of a shaft that moves (which powers the compressor portion) from the kinetic energy of exhaust gas flow using a set of blades. The turbine itself can spin at speeds of up to 250,000 rpm, and the turbine housings control the direction of the gas flow through the turbine section. Numerous turbine housing alternatives are offered for some turbocharger types, enabling the user to choose the housing that best suits the engine’s characteristics and performance needs.

The size of a turbocharger and the disparities in size between the turbine wheel and compressor wheel have a significant impact on its performance. Large turbines often demand greater exhaust gas flow rates, which raises the boost threshold and lengthens the turbo car. Small turbines can produce boost quickly and at lower flow rates because they have less rotational inertia, but they can also limit the engine’s ability to produce peak power. Many different technologies, some of which are discussed in the following sections, try to combine the advantages of both small and large turbines.

A single-stage axial inflow turbine, as opposed to a radial turbine, is frequently used in large diesel engines.


To take advantage of the pulses in the flow of the gases from the exhaust of each cylinder, a twin-scroll turbocharger uses two distinct exhaust gas inlets. The exhaust gas from all cylinders is mixed in a typical (single-scroll) turbocharger and enters through a single intake, interfering with the gas pulses from each cylinder. The cylinders are divided into two groups for a twin-scroll turbocharger to optimize the pulses.


A Porsche variable-geometry turbocharger in cutaway perspective

When operating conditions vary, variable-nozzle or variable-geometry turbochargers are utilized to modify the turbocharger’s effective aspect ratio. This is accomplished by using movable vanes that control the flow of gases toward the turbine and are situated inside the turbine housing between the inlet and turbine. To open and close the vanes, some variable-geometry turbochargers employ a rotary electric actuator, while others use a pneumatic actuator.

Turbochargers with electrical assistance

In order to decrease turbo cars, an electrically-assisted turbocharger combines an electric motor with a conventional exhaust-powered turbine. This contrasts with an electric supercharger, which also powers the compressor with an electric motor.


Garrett GT30 compressor component with the top portion off.

Through the engine’s intake system, the compressor pulls in outside air, pressurizes it, and then delivers it (through the inlet manifold) into the combustion chambers. An impeller, a diffuser, and a volute housing make up the turbocharger’s compressor section. The compressor map provides information about a compressor’s operational characteristics.

Ported cloak

A “ported shroud” is a design feature of some turbochargers that allows air to flow around the compressor blades through a ring of holes or circular grooves. Ported shroud designs may be more resilient to compressor surges and increase the compressor wheel’s effectiveness.

Center hub rotating assembly

The shaft that connects the turbine to the compressor is housed in the center hub rotating assembly (CHRA). The turbo lag can be decreased by using a lighter shaft. [39] The CHRA also includes a bearing, which enables this shaft to move with little resistance at high speeds.

Some CHRAs feature pipes that allow the engine’s coolant to pass through them and are water-cooled. To prevent the lubricating fluid in the turbocharger from overheating, water cooling is one benefit.

Advantages and Disadvantages of Turbochargers:


  • Increased Power: Without increasing engine displacement, turbochargers significantly increase engine power output.
  • Enhanced Efficiency: Turbochargers improve fuel efficiency by optimizing the use of exhaust energy.
  • Reduced Emissions: Turbocharged engines can be built to adhere to strict emission regulations.
  • Downsizing: Without compromising performance, manufacturers can swap out larger engines for smaller, turbocharged ones.


  • Turbo Lag: It takes a moment for the turbocharger to spool up, leading to a delay in power delivery.
  • Increased Heat: Turbochargers generate heat, necessitating additional cooling measures.
  • Potential Wear: Turbochargers operate at high speeds and can experience wear over time.
  • Cost: Designing, manufacturing, and maintaining turbocharged engines can be more expensive.


The development of the turbocharger is evidence of human creativity in the quest for effective power delivery in gasoline engines. The turbocharger has changed the way we think about engine performance since its development more than a century ago and integration into contemporary vehicle engineering. The advantages it offers in terms of power, efficiency, and pollution management are beyond dispute, notwithstanding the difficulties it poses.


What is turbocharger rebuilding?

In order to improve a turbocharger’s performance, it must be disassembled, cleaned, repaired, and then put back together.

Can any engine be equipped with a turbocharger?

Many engines can be turbocharged, but not all of them are appropriate. To bear more stress, an engine may need to be strengthened and modified.

Is turbocharging only for performance cars?

No, turbocharging has been included in popular cars to increase fuel economy without reducing power.

Do all turbochargers produce the same amount of boost?

No, factors like turbocharger size, design, and engine requirements affect how much boost is produced.

Can I add a turbocharger to my existing car?

It is feasible, but it frequently calls for substantial alterations and experience to guarantee effective integration and performance.