Turbocharger: Description and Operation

PURPOSE/OPERATION
Two turbochargers are used to increase engine output by providing a denser air/fuel charge to the engine than could normally be attained. Each turbocharger uses exhaust gas heat and pressure to drive a turbine rotor which drives an impeller. Turbine speed increases with exhaust gas flow, causing intake manifold air pressure to increase, increasing engine output. The turbocharger has an operational range of approximately 20,000 to 110,000 rpm. The turbocharger turbine/impeller shaft rides on two full floating bearings, which are lubricated with crankcase oil under pressure from the engine oil pump. To prevent the bearings from overheating, engine coolant is circulated around them.This vehicle is equipped with two turbochargers, having small diameter turbine wheels with low rotary inertia. The lower inertia allows the turbine sections to accelerate much quicker than a single turbine of equal output. This provides a reduction in the driveability problem know as "turbo lag".