The turbine housing has a spiral design and it is typically made of steel or cast iron. Its main function is to collect the exhaust gases from the engine, before directing them into the turbine wheel. As a result of this, the wheel rotates. Turbine housing increases exhaust drive pressure and also controls boost and exhaust pressure. The size and radial shape of the housing impact on the performance of the turbocharger.
The turbine housing is an essential part of a turbocharger because if it cracked or worn out the turbo will not generate boost pressure correctly.