Do standard petrol turbo cars have dumpvalve's in them?

Question

I have a mk 4 astra turbo and everytime i change gear it makes a faint air releasing noise! car is totally standard so is this normal?
Car runs great with no power loss at all

Answer 1

NO NO NO NO NO!!!!

Too many people with not enough knowledge on this site!!!

A dump valve "dumps" unused air out to atmosphere when the accelerator pedal is lifted (ie changing gear). This is because if it didn't then the air would have nowhere to go and would stall the turbo. Then you'd put the foot down again and get horrendous turbo lag.

Older cars did not have dump valves.

Modern cars also do not have dump valves. They have recirculating valves. Instead of dumping the air to atmosphere, they sent the air back around to the other side of the turbo and put it back into the system. This keeps the turbo spinning and reduces lag.

Wastegates are completely different all together. They are safety valves that stop the turbo overboosting. Tuners sometimes fit stiffer springs to wastegates to raise the boost level, but this can be dangerous to your engine.

As stated, some "boy racers" fit dump valves to their cars to make a "lovely" wooshing noise.
What they don't realise is that they are reducing the performance of their car.
The engines are mapped to use recirc valves, so when they change them to dump valves, they're indirectly messing around with the engine management computer. The computer thinks it should get x amount of air and so puts in y amount of fuel to mix with it, but the engine is only getting z amount of air and so the mixture is too rich and doesn't burn correctly. Result - loss of power.

If it aint broke - don't fix it!

Answer 2

Yes of course my friend. But there are many different types of settings. Some manufacturers set the dumpvalve in a way that you won't here the noise but others that have been modificated, will be heard as an aircompressor. But every petrol turbo car has one. It's there to release the excessive air that the turbo has produced.

Answer 3

Yes, all petrol turbos have a dump valve. Its purpose is to give the turbo boost pressure somewhere to go when you let your foot off the throttle otherwise you would have serious problems and the faint WHOOSH sound you are hearing is perfectly normal.

The boy racers amongst us will no doubt have fitted modified dump valves which make an exaggerated WHOOSH sound which can clearly be heard by all and sundry, but which make no difference to the performance of the car whatsoever.

Cheers

Geordie

Answer 4

Turbo cars are more efficient compared to the non turbo cars. But because they produce more power they use more gas. In general, all Subaru's use more gas than other cars with similar specs. A twin turbo Subaru is definitely a gas guzzler. Without the turbos, the performance will drop so much that you will hate the car.

Answer 5

Some have them, some don't. Somebody used to drive by my flat often in a Renault 5 Turbo - sounded bloody mint with the mighty whoosh!

Answer 6

It could have a dump valve, i've got a Golf GTI 2.0. It does the same thing, and it's fine. Mines had some tunning, but i've not installed a dump valve.

Answer 7

YES...Dont mess with the turbo it can effect your performance severely.Get A PROFESIONAL to mess with it that knows what thay are doing.

Answer 8

isn't that what turbos do? unless the car has only just started doing it i wouldn't worry. check out this link it may help put your mind at ease http://en.wikipedia.org/wiki/Turbocharger

Answer 9

Yes.

Answer 10

Yes,here we call it a waste gate.