Wategate flutter? Or just an echo?

[Animal Mother]

Took the S6 for a cruise today, it was nice and warm so I had my window open.
Because I had the window open I could hear the turbo spool up, but I could hear another noise.
It sounded, to me, like the wastegate was fluttering open and closed rapidly. Car is boosting well to 1.4bar (2.4 on gauge) and seems to drive fine (now I've tightened up the spark plugs).
Now, is this an actual thing I was hearing OR was it a case of sounds echoing off walls?
If it is a known wastegate problem, is it a dodgey N75?

Cheers

[GT500]

I would be guessing on the useless Bosch bov has split its diaphram.

[Animal Mother]

I would be guessing on the useless Bosch bov has split its diaphram.

Nope. I have a fully functioning Bailey DV.

Noise was not like turbo stall/wastegate chatter as associated with knackered DV when coming off boost. The sound I was getting was as it was boosting and seemed to be more of a sound like boost wasn't increasing smoothly, more like the WG was opening and closing quickly. Or just an echo from a wall at the side of the road.

[Acidburn]

was it around 3.5k rpm and 4k?

[Animal Mother]

No higher than 4k, I reckon between 3-4k sounds about right.

Why? You have an idea??

[Acidburn]

I have noticed the same thing on mine but its very rare and mostly coming on boost in third, s2driveruk gets the same thing on his.

[Animal Mother]

Waddya reckon it could be? Weak N75? Weak WG spring?

[newsh]

Maybe you're hearing the WGFV modulating the boost?

Does the boost guage flicker? Mine used to do this, had a leak at the pipe where it goes onto the ECU, trimmed the pipe back and used a new clip. hasn't done it since.

[Acidburn]

My gauge is a constent reading no flickering, I did notice andy casey's do this at the RR day's as he was working out why it was doing it and his readings was playing up as well around the rpm readings I gave above.

[dest]

It is NOT wastegate flutter, its air coming back over the compressor blades.
Perfectly safe unless its running big boost

[Animal Mother]

It is NOT wastegate flutter, its air coming back over the compressor blades.
Perfectly safe unless its running big boost

It is NOT air coming back over the compressor blades.
That is turbo stall and happens when you come off boost and the DV doesn't work.
What we are talking about is a inconsistent spooling sound mixed with a valvey on off sound when boost increases.

[Wiell]

I do

I do belive is the wg working. but may be slightly worn so its not working as fast as it should there for you here the sound.
i hade mine rebuilt. it was really worn out. buying a new one wasnt an option. 12600 sek =1070gbp
i have heard this sound from other s2.

[Rusty]

Mine flutters wildly at full boost between 3k and 3.5k and then it settles. Very strange and not got to the bottom of it, nor does it cause me any probs. Strange though

Perhaps a new WG diphragm might be an idea although it dodn't look too bad when I had a look.

[Bram]

Mine does also flutter in 3th gear and highergears on full boost from 3300 till redline.
The turbo boost meter remains stable al the time, so I am almost sure there is no leak in the boost circuit. I do now that the ceramic ring in my WG lost a small part when I dropped it on the floor. Now I have a new one and will fit is next Friday. Will let you know if the flutter has gone or not.

[gedu]

My UrS4 has this sound also, and it's been there all the time I've owned my specimen. Or rather, nowadays it doesn't have it, as boost control is quite forgotten piece of electrical wizardry (1.7bar boost, yes, the turbo lifetime is quite short, luckily I have new one on order) We'll see how Tial unit sounds like in a few months