Wastegate Chatter

[Gord R]

Hi Guys,

Iv got a 03 A4 1.9 tdi which has been remapped.

I get what sounds like wastegate chatter when backing off and changing gears. I wouldnt normally worry about this on a turbo car, but Iv been told with it being a vnt turbo I shouldnt get the noise?

Is this correct and likely to be a boost leak? Or is it nothing to worry about, I do get quite abit of smoke as well but I had put this down to the map or the egr needing a good clean.

Thanks

 

[chrisash32]

Quite interested to hear the answer to this as I have recently got the same on mine.

 

[Widemonkeys]

I have the same but I dont have a remap I started to get it after a service. I gave no lag when accelerating but do sometimes get some smoke.

 

[Oakie72]

Not sure with tdi's but on petrol turbos you get the chatter when the dump valve fails. Basically instead of dumping the boost pressure when closing the throttle body (letting of he accelerator) the pressure gets forced back into the turbo. The noise you hear is the air hitting the blades of the turbo.

 

[Widemonkeys]

So not a good thing then

 

[Gaz!]

Exactly what Oakie72 said, this is a common misconception, the noise you are hearing is not ''waste gate chatter'' that would only occur when the actuator or WG springs are unserviceable, in 30 years of spannering I have yet to see this.

What you have is compressor surge, this is when you let off the throttle, the pressure difference is felt at the blow off/ dump valve / recirc valve, but the valve doesnt release the pressure and it hits the compressor blades.

With a steel bladed turbo it's not to bad, if though on a ceramic turbo.... bye bye turbo.

Check the recirc valve, it my not be recircing the left over boost pressure and check for the vacume hose hasnt become trapped.

 

[j033y]

I love the sound of wastegate chatter. Wish mine did it lol!!