Turbo noise

[Hobnob]

Ok guys I'm new to the Golf so bear with me,

I have recently bought an X reg 1.8T and I'm hearing some noises when I change gear / let off the accelerator. The noise sounds like a chattering, I tried rining VW about it but was informed they cant discuss technical details over the phone and I would have to pay about £50 for a diagnostics check.

Can anyone tell me should I be hearing a chattering when lifting off, I have heard some people saying it could be the diaphram on the waste gate or something? I am taking the car back to the garage for some wok that needs doing and need to know if this is a problem as I already have a long list (rattles, clunking, temp gague not working etc)

Would really appreciate your feedback as I have only ever driven a turbo diesel so dont know if this noise is correct.

[J2theIZZO]

Most likely the diverter valve will need replacing, probably a good time to buy a forge or bailey replacement.

[BOGGLE]

Yeah that sounds about right, your plastic diverter valve is probably shagged.  You've now got a damn good excuse to get a better one.  I've got a bailey which i'm well chuffed with but i'm told that the forge is much better

[Hobnob]

Ok bear with me because as I said I'm not a big car expert I know the basics but need some explanations

what exactly is the diverter valve? I assume this is similar to a dump valve to stop excess pressure from going through the turbo?

If the above is correct then what would replacing this for a better one achieve?

Also since this has been present since I bought the car is it affecting the performance? I can't tell as I have never driven this car without this fault

Again I really appreciate the replys

[J2theIZZO]

Reason to replace with a Forge unit or simlar is simple, the standard bosch one is made of plastic and what has happened to yours is a common fault, so replace it with a forge unit and you shouldn't get this problem again.

My understanding of it is that a diverter, instead of releasing the pressure back into the atmosphere like a dump valve, releases it back into the system (so sort of recycles the pressure).

I think if yours is leaking, the ECU will try to compensate for the loss of presure by forcing more air in, so it could be working overtime to compensate, although this might only be in extreme cases, or I could be talking complete rubbish, i'm sure someone else can help you more 

I've only owned my 1.8t for 2 days, so i'm in the same boat as you, although mine doesn't give this "chattering" sound, you can hear a faint dump valve, probably the pressure being released though the intake.

[Hobnob]

thanks for the feedback, it is sort of a faint dump valve noise but comes in threes rather than one pshhhh its more like pshh psshh pshhh quite quickly

[J2theIZZO]

Yeah, mine is just a "ppsssshhht"  ..... I love it 

[J2theIZZO]

http://www.forgemotorsport.co.uk/content.asp?inc=product&cat=0006&product=FMCL007P

Look at the above link, ring VW to see how much a new diverter valve is (inc fitting) then decide yourself 

[Dizzie]

The 'Chatter' is caused by the pressure shook up by the wastegate and coming out of the intake.

If you've replaced the box with a cone intake this will be a lot louder than it was originally. It also can be caused by a all too common worn recirclulating dump valve.

The dump valve drops the pressure back into the intake to keep the turbo spinning during gear changes and reduce the turbo 'lag'.

[SmeeDub]

looks like i'm in the same boat as you with the diverter valve, i thought it was supposed to make that noise. seems i'm wrong and now i'm weeping cos i like the noise. will the poorly valve lower the performance and raise fuel consumption?