This is confusing but need someone who knows fair amount on turbos

[craig20102010]

I understand how they work and everything so your not speakin to a complete idiot what i cant understand and its probably really simple is why putting a dump valve on a diesel car is pointless compared to a petrol....


now i understand theres no way of making a dump valve work on a diesel unless its electronic due to there been no vacume in a diesel and also that the diesel engine is controlled by fuel meanin no blanking plate on the throttle when you let off accelerator meaning pressure continues to go into the engine since it can cope with 600x more then it needs at idle..

But why is it not good for a diesel to have a dump valve on it?? is it because it always needs the pressure going into the engine for it to run effectively?

Surely its doin the same as a petrol one? keepin the turbo spinning fast ready for the next burst of power?

i just dont quite understand why there are no extra power gains from this??

lol and No - im not thinkin about getting one lol its just something thats been doing my head in tonight for some reason haha since iv bin tellin my mate how a turbo works and why increasing boost and releaving pressure from the exhaust etc helps on most turbo'd cars

Also just to add.... Whats the waste gate protecting on a diesel.. is it just stoppin the turbo spinning up too fast? cuz on a diesel it just dumps it back into the exhaust system. im guessin theres a sensor on the engine tellin it theres to much pressure going in so it needs to dump it for either the engine or turbo or both?

my friends after his has been remapped you can hear the waste gate dump the excess pressure back into exhaust.. his is the 1.9 active bravo 120Bhp

so i guess i fully understand it on a petrol just not so much on a diesel...

 

[craig20102010]

iv got me head around the waste gate side of things now.. its just to protect over boosting, which all turbo cars have.. only the petrol has a dump valve due to it havin the cut off plate..

still dont know why a dump valve on a diesel is not benefitial though..

 

[D4nny8oy]

Surely its doin the same as a petrol one? keepin the turbo spinning fast ready for the next burst of power?

i just dont quite understand why there are no extra power gains from this??

Dump valves don't gain you power, they're only there on a petrol engine as the closed throttle butterfly causes the pressurized air to back-up and stall the compressor wheel. The dump valve opens to relieve the pressure and redirect the air back into airflow before the compressor inlet or to atmosphere.

A Diesel doesn't have a butterfly (in the same way as a petrol engine) to block the airflow, so a dump valve isn't needed.

 

[craig20102010]

Dump valves don't gain you power, they're only there on a petrol engine as the closed throttle butterfly causes the pressurized air to back-up and stall the compressor wheel. The dump valve opens to relieve the pressure and redirect the air back into airflow before the compressor inlet or to atmosphere.

A Diesel doesn't have a butterfly (in the same way as a petrol engine) to block the airflow, so a dump valve isn't needed.

yeh i got that it wasnt needed for that reason that you explained but i thought they actually made a diesel engine run worse?

i just know that on most petrols to upgrade to stage one turbo they need a better dump valve guess thats just to allow it to release more pressure faster then...

 

[D4nny8oy]

i just know that on most petrols to upgrade to stage one turbo they need a better dump valve guess thats just to allow it to release more pressure faster then...

I think you're confusing a dump valve with an uprated turbo actuator (which has more preload and opens the wastegate at a higher boost level).