can anyone tell me what the difference between a dump valve and waste gate is please?
i had my mind set on buying a dump valve for my classic sti this week but i heard a pulsar turbo and i was told that it had a waste gate on it and it sounded PHAT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! cheers jay

 

a wastegate opens to let out extra boost at a set limit (all turbos have some sort of wastegate most bulit in to the turbo) with out a dump valve this can make a flutter nosie when leting off the gas (scoob would need a fmic for this to happen ) not a good idea to do this long term

 

A wastegate is on the exhaust side, i.e. it relieves excess exhaust gasses once the turbo is producing the required amount of boost. It is a 'gate' for 'waste' exhaust gasses, ones which don't go through the turbo to power it's turbine.

A dump valve is on the inlet side of the engine, i.e. the air side. It relieves excess boost pressure before the compressed air goes into the engine, typically when you change gear. This could be mounted close to your intercooler - whether it's front or top mount.

This dump valve will give a phssssstttt sound while the wastegate will 'chatter'.

 

Thing is don't you have to have some big arsed laggy turbo in order to have to have an external wastegate?

Like the noise but don't really like big laggy turbos.

 

Most of the noise that people incorrectly attribute to the wastegate is, in actual fact: the sound of the turbo stalling due, to the car not being fitted with an air-bypass valve*.

You can have an external wastegate with any size of turbo; its the 'big-arsed' ones that dont incorporate an internal wastegate.....


Simon

*edited to add; that Im talking about competition cars only here!

 

i have a greedy td05-18g with an exturanl wastegate and screemer pipe its very noisey under boost and not a great sound would perfer it to be plumbed in to downpipe to cut the noise but that would cause to many problems

 

probs go for a dump valve then, thanks alot people. jay

 

If you want the wastegate chatter, all you need is to block off the dump valve. One of which your car has as standard anyway.

As simon says the noise is compressor surge, and has nothing to do with the wastegate. You may not hear it with the standard airbox on.

Dave