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cold side relocation done, now boost gauge is reading lower?

Discussion in 'A3/S3 Forum (8L Chassis)' started by russwuss, Dec 9, 2013.

  1. russwuss
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    russwuss Active Member

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    [Dec 9, 2013]
    Hi All,

    As title really, I've done the cold side relocation (as shown in the pic) and now the boost gauge is reading max 12 - 13 psi on full boost.

    The car doesn't actually feel like it's boosting less than before, I just wondered if this was normal?

    Boost gauge is T'd into top of the DV.

    Thanks!

    [​IMG]
    IMG_0298 by russwuss, on Flickr
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  3. IrishDave
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    IrishDave Active Member

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    [Dec 9, 2013]
    I could be totally wrong and probably am, but shouldn't the boost guage be t'd in elsewhere such as the manifold.
    #2
  4. Lavis89
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    Lavis89 Active Member

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    [Dec 9, 2013]
    some people T it from the FPR, others (and me) T'ed it from the vac line that comes off the top of the DV
    #3
  5. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Dec 9, 2013]
    What did it read before? Is it mapped?
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  6. russwuss
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    russwuss Active Member

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    [Dec 9, 2013]
    Same here, mines T'd into the vac line on top of the DV that goes to the inlet manifold - it did read perfectly fine before, about 20 - 21 psi on full load but since doing the cold side relocation it's changed :-/
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  7. russwuss
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    russwuss Active Member

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    [Dec 9, 2013]
    About 20 - 21 psi, yep it's stage 1 r-tech remap. Car doesn't feel like it's under boosting at all.. Just can't explain the change.
    #6
  8. Dani_B19
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    Dani_B19 Audi-sports own special child.

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    [Dec 9, 2013]
    Vac leak, faulty boost gauge, caught vac line feeding boost gauge, DV fitted right way round?
    #7
  9. russwuss
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    russwuss Active Member

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    [Dec 9, 2013]
    DV is definitely fitted right way round, I'll check all the others at the weekend - hopefully will be fitting a catch can. Cheers for the tips!
    #8
  10. Lavis89
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    Lavis89 Active Member

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    [Dec 9, 2013]
    getting the vac line going to the boost gauge snagged is always a good shout, i managed to do it... twice... on the same day....
    #9
  11. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Dec 10, 2013]
    leaking dv?
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  12. Alex C
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    Alex C Well-Known Member

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    [Dec 10, 2013]
    pressure drop through the intercooler?

    but your still reading the pressure from the inlet manifold... don't know
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  13. russwuss
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    russwuss Active Member

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    [Dec 11, 2013]
    Cheers for replies all!

    I'll check for snags on the boost gauge feed this weekend, DV shouldn't be leaking.. Brand new one fitted in March, any easy way to check it for leaks?

    Pressure drop through intercooler is possible isn't it? I've got custom made alloy pipes for the intercooler and the cold side outlet is just welded onto there (not sure if you can see on the pic) N75 is still going to normal place on the charge pipe with the DV port blocked off.
    #12
  14. russwuss
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    russwuss Active Member

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    [Dec 11, 2013]
    I've got loads of vac hose, so I'll T into fpr line and see if it makes a difference.
    #13
  15. Alex C
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    Alex C Well-Known Member

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    [Dec 11, 2013]
    Well that was my instant thought reading your OP

    But boost gauges are normally tee'd into the top of the DV (as yours is), which is essentially reading the inlet manifold pressure which is the same regardless of whether you have a cold side relocation or not. Maybe the pressure on back side of the diaphragm/piston makes a difference... but it shouldn't.
    #14
  16. slowcoach3
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    slowcoach3 Active Member

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    [Dec 11, 2013]
    Please don't tee into the fpr line, it needs to be left alone as you don't want anything messing with your fueling, if you do then your penis will shrivel, your hair will fall out and you will start supporting man city.
    Best guess is either something has been disturbed during the installation or it's a dodgy gauge which isn't unheard of.
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  17. S3 zombie
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    S3 zombie New Member

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    [Dec 11, 2013]
    How do you know you had 20/21 psi before fitting the gauge?
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  18. russwuss
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    russwuss Active Member

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    [Dec 12, 2013]
    The gauge has been fitted for a few months, the reading changed from 20/21 psi when I installed the cold side relocation.
    #17
  19. russwuss
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    russwuss Active Member

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    [Dec 12, 2013]
    message received haha.
    #18
  20. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    right, got some time today to look and think i've found the issue... the nipple under the inlet manifold was cracked, literally touched it with my hand to check the condition of the pipe and it came off........ does this mean i need a new inlet manifold or is there some other way to fix it?
    #19
  21. StaceyS3
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    StaceyS3 Well-Known Member

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    [Dec 13, 2013]
    Could drill and tap it for a hose tail fitting?

    Think May still have some with a 5mm nipple in my garage from when made my inlet mani

    If interested and can find them your more than welcome to one :)
    #20
  22. s3dave
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    s3dave TFSI Hybrid

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    [Dec 13, 2013]
    sure its broke off and not just fallen off?
    #21
  23. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    I've never used a tap in my life.... :-/Is the ones you have the same as this one? 1/4 Bsp X 3/16 = 5 mm Brass Hose tail x 1 b154 | eBay so, do I need to drill, then tap a 1/4" bsp thread and the hose tail will screw right in? :)Sorry for the dumb questions... Brother may have one of these hose tails and taps at work but if he doesn't I would be very interested in one from you :)thanks!
    #22
  24. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    Yep I'm sure.. :( nipple was still in the hose :(

    ImageUploadedByTapatalk1386943710.274224.jpg
    #23
  25. s3dave
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    s3dave TFSI Hybrid

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    [Dec 13, 2013]
    could always block it off and T off the other ones? make sure they are clear as well
    #24
  26. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    now there's an idea.... i'm actually waiting for my catch can to arrive, so having the inlet manifold out the way will make it much easier.I'll be blocking off the big nipple underneath as part of the catch can install correct... ? So rather than blocking off I could run a 8mm to 4mm hose adapter to my DV and block the snapped part up?
    #25
  27. s3dave
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    s3dave TFSI Hybrid

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    [Dec 13, 2013]
    yes, ideal...
    #26
  28. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    Wooohooo :) easy fix... thanks a lot Dave!And thank you Stacey for the offer of the 5mm nipple :)
    Last edited: Dec 13, 2013
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  29. slowcoach3
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    slowcoach3 Active Member

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    [Dec 13, 2013]
    And its a good time to clean the inlet too, tut tut tut :)
    #28
  30. russwuss
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    russwuss Active Member

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    [Dec 13, 2013]
    Two cans of carb cleaner on the way as we speak :)
    #29
  31. russwuss
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    russwuss Active Member

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    [Dec 14, 2013]
    well that's sorted... however now the breather hose decided to snap in half when removing! arghhh!
    #30

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