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What Is a Turbo Compressor?

Posted by Scott Goldfarb on

A turbocharger is commonly used on diesel engines to increase its total power. It consists of a turbine, compressor, and a rotating assembly with a center housing hub. But what is a turbo compressor, and what role does it have?

Our guide includes all the information you need for turbo compressors. We will start by defining the term and explaining how it works. Then, we will continue by looking at the different types of turbo compressors and their applications. Lastly, we will finish by listing turbo compressors' advantages and disadvantages.

Let's get started!

What Is a Turbo Compressor
Source: shutterstock.com/ Photo Contributor: Sanit Fuangnakhon

What Is a Turbo Compressor?

The turbo-compressor and turbine are vital parts of the turbocharger. We refer to the compressor as the cold part of the turbocharger, while the turbine is the hot part.

The compressor works with the turbine to increase the engine's power. Its main job is to compress the intake air before it enters the combustion chamber and feed it to the turbine.

Thanks to the innovative design of the turbo compressor, the vehicle engine can burn more fuel and produce more power. To compress the air, the turbo compressors we use in the automobile industry have two main parts: a compressor wheel and a compressor housing.

However, turbochargers with centrifugal compressors are built slightly differently. Their main components are an inlet, impeller or rotor, diffuser, and collector.

How a turbo compressor works

The turbocharger's compressor utilizes the engine’s intake system to draw in air from the surroundings. A forged steel shaft attaches the compressor to the turbine. The turbo compressor working principle has a radial flow. 

Hence, the turbine can turn the compressor wheel, creating high-velocity spinning that assists with the drawing and compression of the air. What happens next is diffusion, as the compressor housing converts the air stream. 

More specifically, it turns it from high-velocity and low-pressure to low-velocity but high-pressure. Ultimately, the compressed air is pushed into the engine, boosting its power.

Features of turbo compressor

Three primary features of turbo compressors are intake air compression, impeller design and boost pressure. As the compressor wheel spins, it takes the intake air and increases its density. 

Hence, the turbo compressor creates boost pressure, which is measured in pounds per square inch or PSI. The compressed air intake significantly enhances the engine’s power output.

Also, the impeller design is crucial. It includes the compressor wheel design and housing, which must be engineered to efficiently compress air. Plus, the design should optimize airflow and avoid causing excessive heat buildup.

Compressor maps

Examining a compressor map provides insights into the performance of the turbo compressor. The compressor map comes in the form of a chart or graph.

So, here are some of the most important information you can get from the compressor maps:

  • The operating range of the compressor
  • Assessment of how well it works within its operating range
  • Turbo speed
  • Efficiency
  • Boost pressure capability
  • Corrected mass flow rate

Pressure ratios of compressors and boost levers

The compressor pressure ratio and the turbine firing temperature are the main factors for power increase. Knowing the pressure ratio can help you select the most suitable turbo for your application.

As a rule of thumb, the optimum boost pressure ratio is between 4.5:1 to 4.6:1. If the turbocharger works within the optimum range, the compressor will work in two stages:

  • The first stage is the axial-compressor stage, providing a 1.3:1 pressure boost ratio.
  • The second stage is radial and may provide a 3.5:1 pressure ratio.
Pressure ratios of compressors and boost levers
Source: shutterstock.com / Photo Contributor: Guitar Studio

Turbo Compressor vs Supercharger

Many of our clients frequently ask us about the difference between a turbocharger and a supercharger. What sets the two apart is the way they are powered. 

In turbochargers, the compressor fan is rotated from the exhaust gas. On the other hand, in superchargers, the compressor fan is rotated as the belt pulley drives gears.

Types of Turbo Compressors

There are three turbo compressor types:

  • Axial compressor
  • Centrifugal compressor
  • Mixed flow compressor

Axial compressors are known for their efficiency. It is a rotating and airfoil-based compressor that allows the air to flow parallel to the rotation axis. They work in multiple stages and are typically applied in the industrial and aerospace industry.

On the other hand, centrifugal compressors, also called radial compressors, have a rotating set of blades, and the airflow is perpendicular to the axis of rotation.

Moreover, as the name suggests, mixed-flow turbo compressors produce diagonal airflow using axial and radial components.

Applications of Turbo Compressors

Turbo compressors are used in many industries. First, turbo compressors are applied to vehicles such as cars and trucks. Turbo compressors can be used in performance cars and more mainstream models. They allow smaller and more fuel-efficient engines to deliver enhanced power and torque.

In addition, compressors as a concept are also used in marine, aviation, energy, and industrial applications. In the marine industry, there are four different types of air compressors: rotary screw, reciprocating air compressor and low-pressure screw blowers. Marine compressors are widely used and can be applied as a main, deck, emergency and topping-up compressors.

Next, air compressors are used during the aircraft engine manufacturing process in the aviation industry. The two main types are reciprocating compressors and rotary screw compressors. Their purpose is versatile and includes fuel injection, crew area pressurization, air break powering etc.

In the energy industry, air compressors are mainly used for energy exploration. Lastly, industrial air compressors can power air tools, shift refrigeration and air conditioning refrigerants, propel glasses through pipelines and similar.

Advantages of Turbo Compressors

The advantages of turbo compressors range from improved engine performance to reduced emissions. Some of them are the following:

Improved engine performance

The turbo compressor boosts the density of intake gas, enabling improved combustion and processing. This, in turn, enhances the engine's power output.

Better fuel efficiency

Another crucial role of turbo compressors is to contribute to better fuel economy. If they function properly, they will reduce the overall fuel consumption.

Reduced emissions

As turbocharging allows smaller engines to produce more power, the vehicle will probably produce fewer emissions. Hence, turbochargers aid in environmental conservation efforts and reduce the carbon footprint.

Versatile use

Compressors are innovative inventions with versatile applications, ranging from vehicles and diesel engines to various industrial machinery. They can be adapted for a wide range of uses.

Disadvantages of Turbo Compressors

Besides the advantages, there are several challenges to using turbo compressors. They might be:

Turbo lag

The higher compression from the turbo compressor will make the turbo hit full booster faster. Turbo lag is caused by inertia, friction and compressor load. So, if the compressor loading is compromised, the turbocharger might experience turbo lag or delay.

High cost of installation and maintenance

With great power comes great responsibility. If you decide to get a turbocharger with a compressor and turbine, you must be prepared to pay high installation costs. They are complex systems and must be properly installed into the engine.

In addition, regular maintenance is recommended to prolong the lifespan of the turbo compressor. Proper care will also assist in maintaining the turbo compressor's efficiency.

Potential for overheating and thermal stress

Many compressors operate at high temperatures and work at high rotation speeds. Hence, one of the disadvantages is that they can overheat or experience thermal stress. You must ensure an adequate cooling mechanism and lubrication to avoid overeating and thermal stress.

Limited operating range in certain applications

The turbo compressors have a limited range of operation. The design and performance of the turbo compressors generally predict the operating range. For a more detailed overview of the operating range, we advise you to take a look at the compressor map and check the optimal flow rates and pressure ratios.

Limited operating range in certain applications
Source: shutterstock.com / Photo Contributor: snapper8S8

Frequently Asked Questions

What is turbo compressor efficiency?

The efficiency of the turbo compressor is shown in the compressor map. The compressor efficiency is, in fact, adiabatic efficiency.

Is a compressor the same as a turbo?

A compressor and a turbo are not the same. In fact, the turbo compressor is part of the turbocharger. Thus, the turbocharger is a more complex device that includes the compressor and the turbine.

What is the RPM of a turbo compressor?

The turbine wheel of the turbo compressor can be driven with a maximum of 350,000 rotations per minute. On the other hand, the turbine can spin at speeds between 80,000 and 200,000. 

The entire RMP of a turbocharger can be between 60,000 and 300,000, measured by the outlet's exhaust temperature. The RMP of the turbocharger depends on the diameter of the compressor wheel.


What is a turbo compressor? Understanding it will enrich your knowledge about the working principles of turbochargers. The turbo compressor and the turbine are responsible for the turbocharger's proper and efficient work.

Turbo compressors enable engines to produce high power outputs without drastically influencing the size and weight of the engine. There are also different types of compressors, each with pros and cons.

So, explore our inventory if you need high-quality diesel parts, such as turbochargers, injection pumps and much more!


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