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Wastegate flutter?

Discussion in 'A3/S3 Forum (8L Chassis)' started by s3 Hoggy, Feb 15, 2010.

  1. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    Hi all,

    I have just had a forge TIP fitted and I seem to have developed a flutter on lift off? am I right in thinking this is very bad? I have a forge 007p recirc valve and it usualy gives me a light woosh sound but now thats completely gone!
    Any help would be fantastic as I'm quite worried at the moment as not sure if this is damaging my turbo?:sadlike:

    Cheers Matt
    #1
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  3. 16Klappe
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    16Klappe Princess Clap.

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    [Feb 15, 2010]
    I'm not sure if it works in the same way with recirc's as atmospheric (in fact I think it doesn't!) but wastegate flutter basically means that the air is passing back through the turbo and effectively stalls the turbo. So yeah it isn't good!

    Does it happen if you lift off quickly? I'm fairly sure that the main cause of flutter is when the throttle plate snaps back quickly, or if the throttle plate isn't opening quick enough you can get a bit as well.

    It's all down to the throttle plate really, try gently working it up to boost by slowly accelerating in 2nd or third up to about 2 and a half/3K and see if you can hear a bit of chatter on the way up to full boost pressure. Let us know what its doing under those sorts of conditions and we might be able to help :)
    #2
  4. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    hello mate thanks for the reply there is no flutter on the way up or on boost only when lifting off? Could it be down to the recirc valve?
    #3
  5. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    I'd Just like to add im not driving hard as I have just had a new clutch fitted today also

    Cheers Matt
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  6. voorhees
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    voorhees Moderator Staff Member Moderator

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    [Feb 15, 2010]
    I get it and also I know minty has it as well and we are still good
    #5
  7. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    Thanks Jase I was hoping for a reassuring comment! the work was all done at APS I phoned them and they seem to think its fine also

    Cheers Matt
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  8. golf
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    golf ***** rent boy VCDS Map User

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    [Feb 15, 2010]
    A fluttering sound should never be heard from any of the DV's on a 1.8T.
    #7
  9. s3gav
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    s3gav Member

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    [Feb 15, 2010]
    mine does it to has done since i fitted my forge dv over a year ago never had a problem
    #8
  10. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    I think I'm going to take my recirc valve off at the weekend and re-fit the original one? might be worth a try to see if theres a problem there, It just seems wierd as its only started today after fitting tip and now lost the boost dump sound?

    Cheers Matt
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  11. Andrew@A.L.D
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    Andrew@A.L.D May add NOS to 600+bhp?

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    [Feb 15, 2010]
    Spring in the recirc valve to stiff?
    #10
  12. s3 Hoggy
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    s3 Hoggy Whats going on???

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    I was thinking that but its just the standard spring? would it make this flutter if its not dumping properly?
    #11
  13. R-Tech-Nick
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    R-Tech-Nick Member

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    [Feb 15, 2010]
    It should not flutter with the green or yellow springs, I would check all the small vac lines, Check the line going to the top of the DV and see if its pulling a vac on idle.

    Nick
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  14. Andrew@A.L.D
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    Andrew@A.L.D May add NOS to 600+bhp?

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    [Feb 15, 2010]
    The valve could be sticking? No or little vacuum to operate the valve?

    Is there any fault codes coming up?

    If the N112 valve is faulty then its may not open the valve?
    #13
  15. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    If I were to check this would I just take the pipe off and start the engine an see if its sucking? sorry im not very technical!

    Cheers Matt
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  16. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    Woohoo I've just found a split in the small pipe going into the top of my 007p! Would this be causing my problem? It seems it would!

    Matt
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  17. Matt82
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    Matt82 Active Member

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    [Feb 15, 2010]
    wastegates do not flutter
    #16
  18. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Feb 15, 2010]
    I would think so... if that pipe is split then the DV won't be working 100% thus not dumping the excess pressure and bringing on the onset of compressor stall which sounds like the noise you are hearing..

    <tuffty/>
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  19. Andrew@A.L.D
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    Andrew@A.L.D May add NOS to 600+bhp?

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    Arr no vacuum to open the valve, there you go

    Is it better?

    I had that problem with mine were the previous tightened the clip to tight and split the hose
    #18
  20. ianysm
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    ianysm Active Member

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    [Feb 15, 2010]
    Got a pic of this pipe?
    #19
  21. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    I'll get it sorted in the morning and I'll report back, thanks to everyone who's helped out!

    Cheers Matt
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  22. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 15, 2010]
    I'll take a pic in morning mate
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  23. golf
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    golf ***** rent boy VCDS Map User

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    [Feb 15, 2010]
    If it was, indeed, compressor stall then just have a quick look to see that the turbine hasn't been damaged as the shaft of the KO4's are thin and can't take much abuse.
    #22
  24. s3 Hoggy
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    s3 Hoggy Whats going on???

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    How would I have a quick look? Is there an easy way mate?
    #23
  25. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Feb 16, 2010]
    the k04 will be fine.. sustained high boost no DV then yea I would be more worried, but not like you describe.. You wont observe a thing just looking and touching it
    #24
  26. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 16, 2010]
    Cheers Bill
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  27. s3 Hoggy
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    s3 Hoggy Whats going on???

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    [Feb 16, 2010]
    Fixed!!!!!!!!!

    Cheers Matt
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  28. MintyS3
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    MintyS3 Works 60% the time, Everytime.

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    [Feb 16, 2010]
    My n249 valve broke which caused the fluttering on mine, plumber the dv direct to the inlet manifold and its fine although the dump noise does sound different, almost like a slight stall but not sure...
    #27
  29. ALPINE
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    ALPINE Yes its diesel, now cry u lost

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    [Feb 16, 2010]
    whilst were on the subject of VAC etc, My boost gauge only reads -4 to -5 psi of vac. on other turboed cars i have had its more around the -20 mark. i dont have any flutter but when i change gear the needle on my boost gauge flutters down instead of just dropping to -20. Why??
    #28
  30. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Feb 16, 2010]
    idle vac having a small leak would reduce your manifold vacuum on idle.
    if you have vagcom have a look at block 032 and see what % lambda adjust is doing on short term (first block)... a higher +ve number is compensating for additional air getting in... aka leaky pipe
    (up to 3-5% is probably ok)
    #29

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