22-05-2012, 11:13 PM
As Mark said.
Just to expand slightly..
Consider what a turbo does, it compresses the air entering the engine. In a petrol car when you lift off the throttle no air is needed for the engine, but the turbo charger is still spinning away, compressing the air. Dump valves in this case are used to provide an escape route for this excess air, otherwise it may flow backwards and force the turbo to spin in the opposite direction.
We do not suffer this problems with diesel car's, however, because the engine is constantly sucking in air anyway even when we lift off the throttle. It is still possible to fit a dump valve, but they require a micro switch operated solenoid to work so they're a bit naff really.
Just to expand slightly..
Consider what a turbo does, it compresses the air entering the engine. In a petrol car when you lift off the throttle no air is needed for the engine, but the turbo charger is still spinning away, compressing the air. Dump valves in this case are used to provide an escape route for this excess air, otherwise it may flow backwards and force the turbo to spin in the opposite direction.
We do not suffer this problems with diesel car's, however, because the engine is constantly sucking in air anyway even when we lift off the throttle. It is still possible to fit a dump valve, but they require a micro switch operated solenoid to work so they're a bit naff really.
Captain Standard