1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Losing boost...

Discussion in 'A4/S4 forum(B5 Chassis)' started by Geeman, Apr 6, 2009.

  1. Geeman
    Offline

    Geeman Low Life

    Joined:
    Mar 19, 2009
    Messages:
    1,318
    Likes Received:
    5
    [Apr 6, 2009]
    If I give my '00 (83k) 1.8T Sport a fair old boot and take it through the rev range quite aggressively I sometimes lose turbo boost altogether.

    I don't do this very often, so it's not a major issue right now, but I'm sure it could turn into one in the future.

    Once I come to my destination, I switch off, do what I need to do and come back to the car and everything is fine again.

    Am I right in thinking it's the 'N75 valve' that causes this... or is it something more serious? Will the fact that it's been re-mapped have anything to do with it? I've not got any receipts for the work carried out (previous owner lost it) but I do know it's a LOT faster than a standard 1.8T.

    Cheers for any help...

    Giles
    #1
  2. Ads

    Ads

    [Sep 19, 2014]

  3. Geeman
    Offline

    Geeman Low Life

    Joined:
    Mar 19, 2009
    Messages:
    1,318
    Likes Received:
    5
    [Apr 10, 2009]
    Bueller...? Bueller...? Anyone...?
    #2
  4. aragorn
    Offline

    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

    Joined:
    Jan 30, 2008
    Messages:
    15,571
    Likes Received:
    313
    [Apr 10, 2009]
    It could be the map, or it could be the N75 valve allowing the boost to spike too much. Do you have vagcom and have you got any fault codes showing up?
    #3
  5. Broken Byzan
    Online

    Broken Byzan Photographic Moderator Staff Member Moderator VCDS Map User

    Joined:
    Apr 26, 2004
    Messages:
    12,597
    Likes Received:
    274
    [Apr 10, 2009]
    You need to pull he codes, if she is hitting limp mode, it will have regisered a reason
    #4
  6. Geeman
    Offline

    Geeman Low Life

    Joined:
    Mar 19, 2009
    Messages:
    1,318
    Likes Received:
    5
    [Apr 10, 2009]
    Found a few things wrong with it today while we were replacing the timing belt (what a pig of a job!)

    There were TWO dump valves on it... the standard recirculating one in the correct place, then an adjustable atmospheric dump valve between the two outlets on the air intake pipe...?!?!?! (it's got a cone filter on it).

    So, we took the aftermarket item and placed it where the standard one was and then put the engine breather back into the intake pipe and disconnected the thin air-pipes that had been t-boned off the inlet manifold.

    God knows what the person who put this together was thinking...

    Not run it again yet though as I'm waiting on auxilliary drive belts to finish the job off.

    Will let you know if it makes any difference tomorrow when I finish the job off... hopefully - if I can find the belts I need!
    #5
  7. Geeman
    Offline

    Geeman Low Life

    Joined:
    Mar 19, 2009
    Messages:
    1,318
    Likes Received:
    5
    [Apr 12, 2009]
    Think I've fukked up the dump valves by replacing/moving them.

    It's now only half as powerful as it was before. Think I need to get it all back to standard... so I need to find a donor 1.8T for some pipe-work.

    Anyone know of a vehicle that's willing to donate pipe parts?
    #6

Share This Page