Dismiss Notice
Hi Guest, stickers are available from our online store.

This N249 bypass mod, FAO all of those who seem to dont understand it..

Discussion in 'Mk1 Leon Guides (1M) 2000-2006' started by leoncupra2012, Apr 6, 2012.

  1. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    I did this to my cupra 180 earlier, it took less than 10 minutes, i really cant see what the fuss is all about either now !



    Step by step long winded guide, if you cant do it after this then either dont do it or get someone else to lol..

    Basically all you need is about 3/4 a metre of 4mm internal diameter silicon hose like so -

    So buy 1m

    http://www.ebay.co.uk/itm/330671639150?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    Then you need a plastic 6mm at each connection, t piece like so

    http://www.ebay.co.uk/itm/270697911689?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

    Then look at this

    [​IMG]

    1) Remove the black box (red number 3 in picture), which is being pointed at by the lime green arrow, 3 bolts, need a allen key to remove these.

    2) Cut the rubber hose thats going into it (yellow arrow) and then throw the black box away (number 3 again), use one of the bolts youve just removed to remove the box, and shove it down the open end of the hose youve just cut (yellow arrow again) to bung it up.

    3) Remove the top small hose thats coming off your dumpvalve (number 1 in red on the picture), shove another one of them bolts down the open end of that hose to bung it up.

    4) Bin the 3rd bolt or keep it, whatever

    5) Take your new bit of hose you got off ebay or whereever, push it onto the top of the dumpvalve to replace the hose you just removed/bunged up, it goes where the red number 1 is in the pic.

    6) Remove the hose that connects the fuel pressure regulator to the inlet, this goes down behind and underneath, so first remove it from the regulator, (red arrow) if you look where it goes you will see, pull this hose off and discard it, its about 10 inches long and feels like textile/braided.

    7) Take your new hose which you connected to the dumpvalve earlier ( red number 1 in the picture, and feed it down, under however you like and connect it to under the inlet where you just pulled off the old hose that ran to the fuel pressure regulator

    8) So now your new hose should connect the dumpvalve to the inlet, what you need to do here is cut the new hose near the fuel pressure regulator, and insert the t piece to rejoin these hoses, then run the offcut of new hose you should be left with from the left over connection on the fuel pressure regulator

    9) Slap yourself on the forehead after realising how easy it was and for posting 60 questions time and time again on how do it!

    :D
     
    #1 leoncupra2012, Apr 6, 2012
    Last edited: Apr 6, 2012
    Terryrose and Molehill_Mike like this.
  2. BEOWULF

    BEOWULF I am BEOWULF !!!

    Joined:
    Mar 18, 2006
    Messages:
    1,186
    Likes Received:
    0
    Good guide mate do u have to remove the black box i have just left mine on.
     
  3. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    No but it seems pointless just leaving it on there looks better without it mate :)
     
  4. dixonsa13

    dixonsa13 Active Member

    Joined:
    Feb 21, 2011
    Messages:
    122
    Likes Received:
    0
    might seem a dump question but
    what do you acheive by this bypass
     
  5. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    Some say it holds boost better, mine definately felt smoother when boosting/coming off boost, when changing gear instead of the normal tshh its a lot more of a crisp quicker sound. (forge valve)
     
  6. dixonsa13

    dixonsa13 Active Member

    Joined:
    Feb 21, 2011
    Messages:
    122
    Likes Received:
    0
    well mines pretty much standerd under the hood apart from a drilled airbox but every ones on about the bypasses and just wondering what the benefits are to like the n249 and the sai bypass ect
     
  7. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    Whats the SAI one? N112 or something? whats that do?
     
  8. dixonsa13

    dixonsa13 Active Member

    Joined:
    Feb 21, 2011
    Messages:
    122
    Likes Received:
    0
    secondary air intake and no idea thats why i asked lol im thinking bout the n249 bypass and plus it looks neater
     
  9. aaron-gardner

    Joined:
    Apr 15, 2011
    Messages:
    753
    Likes Received:
    0
    the n249 bypass is a simple mod which just eliminates the ecu dumping boost at low throttle and sometimes it becomes faulty and starts dumping boost randomly and can cause jerky pull off. also it helps hold boost for longer. the n112 and sai bypass/ removal are a bit more complex and all require resistors ect.. to bypass. if after doing the n249 bypass you still experience boost issues then maybe a n75/n112 and sai delete is the answer but in my opinion keep it simple and just do the n249 unless you believe or know the rest to be at fault.
    also weather or not your car is standard or modified the n249 bypass works but its best used on a uprated dump valve as the n249 is a protective measure against the stock dv failing.
     
  10. dixonsa13

    dixonsa13 Active Member

    Joined:
    Feb 21, 2011
    Messages:
    122
    Likes Received:
    0
    thanks aaron that makes alot more sense now think i might just do the n249 bypass
     
  11. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    In my eyes and experience if somethings not broke then don't fix it, but with this being such a simple cheap effective mod that you can't really mess up, (ok i managed to bent the bit on my fuel pressure regulator a little getting pissed off the hose clip wouldnt come off ! :rofl: ) then simply why not ! :D
     
  12. ben450

    ben450 Active Member

    Joined:
    Feb 17, 2012
    Messages:
    1,617
    Likes Received:
    2
    This don't cover the LCR though
     
  13. LlamaLord

    LlamaLord Guest

    Does this mod also work for tdi 150?
     
  14. techie

    techie Skoda Techie

    Joined:
    Mar 22, 2003
    Messages:
    5,440
    Likes Received:
    5
    No, you don't have a dump valve.
     
  15. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
  16. Dudfield

    Dudfield Guest

    Pipes on order will be doing this hopefully next weekend. the little black box is flapping around so a great excuse to do it ;)
     
  17. leoncupra2012

    leoncupra2012 Active Member

    Joined:
    Mar 7, 2012
    Messages:
    657
    Likes Received:
    5
    Should be bolted down by 3 bolts? lol
     
  18. Dudfield

    Dudfield Guest

    should be but all 3 plastic brakets snapped oh well lol
     
  19. dan23

    dan23 Guest

    in the first pic why does the red hose come from the n75 and not the top of the dv
     
  20. aaron-gardner

    Joined:
    Apr 15, 2011
    Messages:
    753
    Likes Received:
    0
    its just laid their lol. it does look connected to the n75 tho.
     

Share This Page