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N249 Bypass How To (2000 S3 - but same for many)

Discussion in 'General Technical / How To' started by Welly, Dec 3, 2009.

  1. Benjiman46
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    Benjiman46 R-Tech Terrorist

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    [Apr 17, 2012]
    What does the N112 valve do on an APY engine then?

    I bypassed mine whilst doing the N249 bypass. Left them both electrically connected and it runs fine without it.
    #81
  2. Alex C
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    Alex C Well-Known Member

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    [Apr 17, 2012]
    its for the secondary air injection (SAI)
    #82
  3. Benjiman46
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    Benjiman46 R-Tech Terrorist

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    [Apr 17, 2012]
    Will it affect anything with me bypassing it?
    #83
  4. Schlaag
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    Schlaag Bwah

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    [Apr 24, 2012]
    Good and interesting thread! worth doing on a std car? (AMK engine)
    #84
  5. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jun 2, 2012]
    Just ordered a 1m length (hopefully this is enough) of 4mm internal diameter pipe so think i will give this a go as it sounds a piece of cake on my BAM engine.
    #85
  6. vrbob
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    vrbob Thats no Moon, Thats a space station!

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    [Jun 16, 2012]
    Just to say i did this today on my BAM and it was pretty easy as mentioned.

    i decided to put the plate back ontop of the block so it could support the engine cover and i also put the N249 back on the bracket as it was and still connected but without all the pipework. i only used to of the original bolts to hold the plate down so its still easy to remove when changing plugs etc.

    1m pipe is defo enough to do the job and also keep it neat.
    #86
  7. ceS3r
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    ceS3r Member

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    [Sep 25, 2012]
    Hi everyone. This is my first post here. I'm from Venezuela and have always had problems with my BAM S3. Everything was going ok, just had installed a cone filter, decat and that's it, everything else is stock. So, one day I was just checking some stuff in my engine bay and accidentally broke the hose that goes from the n249 to the vacuum chamber. Now I get a fluttering. It's a really nice sound but yesterday I heard a huge woshhhh on full throttle and then like the dv just released all the air, and the turbo I felt it lowered down the psi. I don't have a gauge yet so I can't tell if it really went down, but from yesterday, I feeling the car with so little power, and I can even hear the turbo whistle like I always do. Every hoses are fine, just checked them, and maybe tomorrow I'm gonna reconnect the hose from the n249 to the vacuum chamber.

    Sorry for the long post, but I'm also considering on doing this bypass. I've noticed that the hose from the mani is thinner than the one that goes on the top of the dv, how can I do here? Thanks in advance. 20120925_172120.jpg
    #87
  8. ceS3r
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    ceS3r Member

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    [Sep 26, 2012]
    UPDATE--
    Ok, so I reconnected the hose today, and the car is not fluttering anymore, but the turbo is inconsistent. It feels like is just a 1.8 without turbo. Thinking it could be the N75 valve?
    #88
  9. turnstyle
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    turnstyle Member

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    [Oct 26, 2012]
    Did this today on my AMK - took all of 20 minutes and cost £2.50 for the vacuum pipe from local car spares shop.
    Great guide and easy to follow
    #89
  10. Birdy
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    Birdy Member

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    [Dec 29, 2012]
    thank god i can get rid of all that pipe work. job for the weekend thanks for the how too
    #90
  11. JudderMan
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    JudderMan Active Member

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    [Feb 2, 2013]
    Did mine today AUM and the mk4 Golf link is the one I followed. Not sure how but I managed to use 2.5m of 5mm hose (the only size I could find but fitted a treat).

    Idle is much more steady as I've had an intermittent problem lately and seems smoother when giving it a boot. Thanks to the OP though for creating the thread, f**k knows what mangled mess I would have done without instructions. Took 2.5 hours as well thanks to the freezing cold and those feckin one-shot clips.
    #91
  12. chrisw_s3mk1
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    chrisw_s3mk1 Member

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    [Mar 3, 2013]
    mate im going to attempt this i need to sort mine out pronto
    #92
  13. Pmol66
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    Pmol66 Member

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    [Mar 19, 2013]
    Where did you order your pipe from mate? Last time i ordered online i ended up with some cheap **** i didnt even use.
    #93
  14. Pmol66
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    Pmol66 Member

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    [Mar 26, 2013]
    I am officially a trained chimp :)

    ImageUploadedByTapatalk1364328086.901712.jpg
    ImageUploadedByTapatalk1364328160.984302.jpg
    ImageUploadedByTapatalk1364328196.067377.jpg
    ImageUploadedByTapatalk1364328208.265319.jpg

    Great thread. Much Thanks
    #94
  15. Pmol66
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    Pmol66 Member

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    [Mar 27, 2013]
    You wouldnt know what sort of electrical cable is best for hiding the valve would you dude? Im just looking on fleebay now. The only cable i have is speaker cable....
    #95
  16. Pmol66
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    Pmol66 Member

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    [Mar 27, 2013]
    Good thread mate.
    I done mine yesterday. Im also going to hide the valve...
    Is there any other use for the bracket except to support the one single pipe.
    Im thinking it would look neater without.
    Thumb up
    #96
  17. Xinxing LI
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    Xinxing LI New Member

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    [Mar 27, 2013]
    i have down mine. 1.jpg 2.jpg
    #97
  18. JudderMan
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    JudderMan Active Member

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    [Mar 27, 2013]
    Did anyone else find that some connectors were 2mm on one side and 4/5mm on the other? I had to tape up the end of the pipes to fatten them out a bit so it was a snug fit.
    #98
  19. nevermore1983
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    nevermore1983 New Member

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    [May 16, 2013]
    Hi just have few questions what size is the vac hose from the diverter valve mine has hole near clips so going to replace it and what size t piece did you use.
    #99
  20. Pmol66
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    Pmol66 Member

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    [May 16, 2013]
    I think its 4 mate and same for the t piece. Thats going off my memory though.......,
    If you read the thread, someone has already asked i think....
    Paul
  21. nevermore1983
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    nevermore1983 New Member

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    [May 16, 2013]
    just double checking i have 4mm and thy one on the DV look thicker
  22. djarchive
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    djarchive Member

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    [Jul 8, 2013]
    Well I've finally done it!!! :superman:

    Did mine on Thursday afternoon. Will most pictures of mine tomorrow (Monday + compare also with whereabouts I stashed my wiring loom/ N249 electrical plug thing) that we need to keep after finishing this "mod".


    ---

    No, 4mm is ample. You need this guys...

    4mm Silicone Vacuum Hose AIR VAC BLUE 2 Metre | eBay


    ---

    I honestly thought it wouldn't fit over the top of my 007p Forge valve, but after a little persuasion, she went on. lol

    Anybody have any questions, please ask me.


    Believe me, It's easy.

    Hardest thing I had was the plastic (cover/ guard) at the front of the engine (in front of the dipstick - with the two round screws). The nuts had rusted & wouldn't budge, so I had to snap it/ break it off to get the dipstick out the way + make some extra room by taking the metal guard off at the front underneath the dipstick holder.

    It's quite hard to explain but looking at the previous pictures it's obvious what I mean. You'll see what I mean when you start as it's easier to see for yourself etc...

    All that's needed then to sort this out is some, allen keys/ bits (think a 10mm for the nuts that held in the vac chamber onto the head), rest is just free'ing up the pipe work off the Audi bomb-proof clips that secure the "plug in" part of the N249. Bit of cutting/ wriggling + more swearing later & it came clear.


    Results: Well, as per somebody else's comments, I have noticed a bit more zip under full load/ boost. Seems to hold boost more steadily + for longer.

    Other then that... Tidy's up the bay alot. That pointless, pipework does my head in.


    :beerchug:


    Joe
  23. Shaunie Eire
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    Shaunie Eire Member

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    [Jul 21, 2013]
    Uh oh, I think I misread something then went hell for leather at it. I have the DV going to the nipple on the manifold and a T piece between them going to the SAI completely bypassing the n112 is this an issue?
  24. BenJee_S3
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    BenJee_S3 Active Member

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    [Aug 28, 2013]
  25. timberman
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    timberman New Member

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    [Oct 27, 2013]
    Hi everyone,

    I did this mod this afternoon but I stumbled on something I founded weird at my APY engine. There were two vacuum hoses at the manifold and both were connected to the N249 instead of one vacuum-hose from the manifold being connected to the N249 and one to the FPR. The N112 had one braided hose going to the SAI pancake thing and one to the FPR:tocktock:. I refitted everything correcly as in the guide but found it strange that the N112 was connected to FPR instead of the FPR to the manifold..

    What kind of problems could the old situation give? It seemed to run pretty ok with the old situation though..
  26. daneastwood
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    daneastwood daneastwood

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    [Nov 23, 2013]
    Sorry to drag this out the depths again but I followed your guide yesterday and have run into some problems the diverter valve is fluttering when letting off the throttle which i have read is not good please can you confirm that i have done this correctley i am pretty sure that its fine. just want the peace of mind and if i cant get it to work going to put it back to standard.

    the clear pipe that is on the right hand side heading down towards the manifold is connected to the n112 valve and the other on the left is the original pipe that heads to the intake manifold. the last pipe that is housed in the clip heads up to the top if the diverter valve.

    [​IMG]

    Any help would be appreciated
  27. Pmol66
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    Pmol66 Member

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    [Jan 25, 2014]
    When i bought mine, it had that fluttering sound. The dv had gone. I actually liked that sound :( someone told me its the sound of the air going back through the turbo the wrong way :S
  28. Mi11ar
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    Mi11ar Member

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    [Apr 15, 2014]
    is this possible on a 99 plate 1.8T Sport?
  29. temp
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    temp Member

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    [Jun 2, 2014]
    Hi I have just bought 1m of 4mm pipe do you think this will be long enough to do n249 bypass on a apy or should I wait and buy abit longer pipe before cut all the pipes on my car.

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