Engine Performance: System: Turbocharger: Description
The Toyota turbocharger unit consists of turbine and compressor impellers, impeller shaft, bearings and impeller housings. The turbocharger is equipped with a wastegate to prevent engine damage from excessive boost pressure. The wastegate opens to prevent excessive intake boost pressure.
The turbine impeller of the turbocharger is driven by the exhaust gases expelled from the cylinder combustion chambers. At idle speeds the engine operates like a normally aspirated engine. As engine speed increases with opening of the throttle valve, the amount of exhaust gas increases. This leads to an increase in the rotational speed of the turbine. The turbocharger is lubricated by engine oil. Lubricating oil is essential in cooling the turbocharger to prevent bearing failure.