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

leoncupra2012

Active Member
Mar 7, 2012
657
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



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
 
Last edited:

leoncupra2012

Active Member
Mar 7, 2012
657
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)
 

dixonsa13

Active Member
Feb 21, 2011
122
0
HUDDERSFIELD
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
 
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.
 
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leoncupra2012

Active Member
Mar 7, 2012
657
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
 

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 ;)
 

dan23

Guest
in the first pic why does the red hose come from the n75 and not the top of the dv
 
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