Turbocharger - Gasoline: Operation

At idle and light throttle, the Turbo engine operates like any other engine. When more power is required, exhaust gases from the exhaust manifold enter the turbocharger's turbine housing and flow through the turbine blades.

Exhaust flow and turbine speed increase as throttle opens and RPM increase. The impeller turns with the turbine and forces air into the compressor housing and intake manifold. The faster the impeller and turbine spin, the more pressurized air is provided for the engine.

If boost pressure went too high, engine damage would result. The wastegate opens when exhaust pressure exceeds a predetermined limit and allows exhaust gases to by-pass the compressor. A boost pressure safety switch is used for protection in case the wastegate fails. This switch is connected to the intake manifold and serves as the ground for the electric fuel pump. When pressure is higher than 11.6 psi (.82 kg/cm² ), the switch opens and the fuel pump stops, slowing the engine.

An electric blower fan is used to cool the injectors and intake manifold and prevent vapor lock. A thermal switch controls fan operation and turns the fan on whenever manifold temperatures exceed 212°F (100°C).

Turbocharger operation requires a large quantity of clean oil to prevent bearing failure. Turbo models have increased oil capacity, an oil cooler, oil thermostat, and special filter. Both the turbocharger filter and the regular engine filter should be changed at regular intervals.