Fluttering / Boost Related?

I’ve got this odd fluttering noise on my Ibiza. Currently have a Forge 007p, green spring and Revo Stage 2, if I put my foot down, let the boost spike and then immediately come off the gas, I get the fluttering sound, almost like an echo noice if that makes sense? Also get the same when driving hard up the gears, sometimes I get the normal tshh noise but not always, mostly on less harsh driving. This has only come on since I maxed out my boost settings on SPS3, if I drop the settings down then the problem gets eliminated. Am I running too much boost maybe? I have replaced all VAC hoses for decent silicone and the 007p has also just been serviced, piston moves freely and passes leak-back test. Have no engine light or VAGcom errors logged. I am not running the N249 bypass by the way, it’s all plumbed in as Seat intended

I realise fluttering may be turbo stall and isn’t good, but I am not sure how to get rid of it!
Any ideas guys?
Cheers…

Don't think induction kits chatter back, the turbo wastegate does if it stalls. As I said, I get the normal tshhh a lot of the the time, but when puching it I get this diffrent sound like an echoey chatter and I am assuming that it's wastegate, I may be wrong as I have nothing to compare to....!

Robbie C said:

Sounds like partial throttle overboost causing compressor surge. What are you peaking at?

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Hi Robbie, I'm peaking at approx 1.6bar / 24ish psi...

Robbie C said:

On a standard k03? Is that reading from a boost gauge?

I'd wind it back a tad and maybe get a log of block 115 to verify how much actual boost you're running

I'm not sure whether a TBA may also help though I feel it's unlikely, but easy enough to try

http://www.ross-tech.com/vag-com/cars/throttlebody.html

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Standard k03 yes, stage 2, Reading from a mechanical boost gauge. Like I say it eliminates when I turn down the boost with my sps3, but I'm after getting as much as I can out of the icle blower

Yes good shout about doing some logging, I've not heard of partial throttle overboost you mentioned earlier, isthis common and my symptoms sound related?

ian_jobson said:

It may be your spring not strong enough for the high boost? what colour spring you got in it?

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Ah ok, would that cause the overboost thing? My 007p's got standard green spring in it. Sounds like I may need a yellow one maybe?!

I think I'll try and grab a yellow spring for starters, then get some logging done and maybe drop my boost down a tad... See what the logs say. Thanks for the info guys

Robbie C said:

I'm not sure it will be down to the spring, surely it's the opposite? A harder spring will more likely induce flutter if it doesn't open as readily as a softer one? If you were loosing boost or dumping more often than expected then I'd say it was more likely the spring but this doesn't sound the case, unless I have misunderstood.

I would try the TBA and then get some logging

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I was thinking the same, but not knowing about the overboost thing mentioned in the thread if the weaker spring would contribute? I realise a harder spring could cause the valve not to open and in turn cause turbo stall... Out of interest, my N249 isn't bypassed and the DV is opened by the black box, is the vacuum on this box greater or lesser than the actual inlet vacuum? Would I be better getting direct vac rather than this electronic box?

Prebs said:

Rob, did you get to the bottom of this as Im still suffering from the same issue.

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Hi Prebs, no not really to be honest. I have since fitted a yellow spring and although the re-circ of air sounds better, I still get the flutter occasionally. I was contemplating an N249 bypass, but I have also read that people get this since doing it. I try an drive around it now, may try the bypass but not sure when yet. Hey perhaps it's actually normal and we are worrying for nothing !!

Something I've not tried is reversing the 007p dump valve, may try this first as it's a simple job and may or may not have a bearing on the fluttering...