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

bov and mbc

Discussion in 'A4/S4 forum(B5 Chassis)' started by s4 osh, May 4, 2009.

  1. s4 osh
    Offline

    s4 osh Member

    Joined:
    Mar 21, 2009
    Messages:
    41
    Likes Received:
    0
    [May 4, 2009]
    right so why is it not good to have a blow off valve, i know some hate the things, so except the chav status whats the other reason not to

    and manual boost controller, if i was to ditch the n75 how can i dissconnect it without the computer spazing out, and any reccomendations on wich one??????
    #1
  2. Ads

    Ads

    [Sep 22, 2014]

  3. jcb
    Offline

    jcb Active Member VCDS Map User

    Joined:
    Sep 19, 2005
    Messages:
    4,118
    Likes Received:
    13
    [May 4, 2009]
    your MAF dependant ECU factors in the recirculating charge into the fuelling equation and can run way off if you vent the charge to atmosphere.
    if you want to run any other kind of controller without the ECU "spazzing out" diconnect the N75 but leave the electrical connection plugged in.

    but honestly, hiking boost, tricking the N75, cranking wastegates etc etc withithout an appropriate remap will leave you lean and kill your turbo or engine or both eventually.
    #2
  4. Blue_Thunder
    Offline

    Blue_Thunder Active Member

    Joined:
    Feb 1, 2007
    Messages:
    1,708
    Likes Received:
    9
    [May 4, 2009]
    Get it sorted before you think about modding it!

    Oh, drew a blank with finding the details of the guy I bought mine from in Anglesey.
    #3
  5. aragorn
    Offline

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

    Joined:
    Jan 30, 2008
    Messages:
    15,573
    Likes Received:
    314
    [May 5, 2009]
    I wouldnt be putting a manual boost controller anywhere near an S4 engine...

    Firstly the ecu will instantly cut the fuel if you boost any more than stock anyway.
    Secondly, if it cant control the boost curve the way it wants to, you'll end up in limp mode.
    Thirdly, if you do get it wrong and put some speed holes in the pistons or blow the turbos, its a very expensive fix!
    #4
  6. s4 osh
    Offline

    s4 osh Member

    Joined:
    Mar 21, 2009
    Messages:
    41
    Likes Received:
    0
    [May 5, 2009]
    cheers guys, thats really great info will steer clear of the mbc, and no mods are going anywhere near the car until its sween as a nut, dont worry im not a dim whitt haha
    #5
  7. andybnwc
    Offline

    andybnwc Member

    Joined:
    Jun 29, 2007
    Messages:
    752
    Likes Received:
    0
    [May 6, 2009]
    I run a mbc parallel only to stop boost and limp mode until fueling and remap is done hopefully in the next few weeks i run low boost just for peace of mind really . But yeh just running a mbc to over boost is not a good idea
    #6
  8. joe_audi1.8t
    Offline

    joe_audi1.8t New Member

    Joined:
    Nov 22, 2008
    Messages:
    10
    Likes Received:
    0
    [Sep 3, 2009]
    i have a mbc on my car leave the n75 in with it still plugged in and connect the two pipes to ur mbc mine seems to be fine holding 1.2 bar.
    #7
  9. Nez
    Offline

    Nez Member

    Joined:
    Dec 6, 2008
    Messages:
    598
    Likes Received:
    4
    [Sep 3, 2009]
    I have get a dump valve on my S4 and its atmosphere and my car is only putting 249.1 BHP meannig its not good to run a dump valve on S4 at atmosphere :)
    #8

Share This Page