Turbocharger 101

How Does a Turbocharger Work?

Nowadays turbochargers are becoming popular among vehicles due to the extra power it produces, it compresses more air into the cylinder to create bigger power for better performance and efficiency. When the density of the air increases by the compressor, more air along with more fuel are pumped into the combustion chamber, leading to greater engine output.

A car engine generally has 4 to 6 cylinders, the more cylinders it has, the more power it produces, that’s why with super cars they may contain up to twelve cylinders. Fuel enters each cylinder and mixes with the air to create a small explosion that drives the piston out for the car to move. Once the piston pushes back, mixture of the air and fuel then releases to become exhaust on a naturally aspirated engine, this contributes to air pollution and not to mention the exhaust still has some leftover energy that goes to waste.

The faster fuel burns in the cylinders (per second) the faster a car goes. On a turbocharged engine, the exhaust is being recycled into the turbine, driving the compressor of a turbo to inject more air, and thus burning fuel at a faster rate, to generate larger power output.

Components of a Turbocharger

A turbocharger has two main sections connected by a central core; turbine is usually presented with red color because of its high temperature, and blue usually goes with compressor as cool air goes through.

Turbine consists of turbine housing and turbine wheel, when the exhaust enters the turbine housing, it propels the turbine wheel to spin. The turbine wheel is attached to the compressor wheel by a shaft, so when the wheels spin, the high-speed rotation compresses and brings plenty of air into the compressor housing, this compressed air is pushed into the piston to produce larger power. Theoretically, the bigger a turbocharger is, the more power it produces as the amount of air pushed into the engine increases; however, there is only so much room in the cylinders to hold certain amount of air and fuel and sometimes when it’s too big the turbo lags before producing bigger power, therefore choosing a proper sized turbo is important.

Exhaust is the heat that comes out of the engine, therefore the turbine housing and the turbine wheel must be able to endure high-temperature. A percentage of Nickel is added to cast iron to make turbine housing. Compressor housing and compressor wheels on the other hand handles cool air, hence is mostly made by Aluminum Alloy.

Cartridge (or CHRA) is the part that holds both turbine wheel and compressor wheels in place, it also connects compressor and turbine housings together. Between both wheels, there sits bearings which facilitates spinning. In general, two types of bearing systems are journal bearing and ball bearing. Each type has its advantage and disadvantages. If you find it hard to choose, Arashi now offers a new type bearing system combining both journal and ball bearing called KURO series.