Removing N249 valve - How To Guide

MC20VT

Guest
You should not get any fault codes at all. If you still get N249 mechanical malfunction and you hooked the DV up correctly then maybe your DV is faulty. As for the N112, did you leave the third nipple of the N112 open? It has to be opened (with the black cap on it).

I'm using a blow off valve, could be this that give the error.

Yes it is the same of original setup, vith a black cap on it. i don't modify it! i must modify and open it?
 

uniseat

technical
Jul 13, 2005
76
0
Holland
www.mijnalbum.nl
Did 2 cars today with the n249 mod, removed the tubing from de valve, placed an splitter. Did some testing, no errors etc.

The cars respond are much better.
Only took me some 15min a car.

Did the mod with a car>>standard chip
Did the car with a special chip on max boost 1,5 bar.

2 cupra riders that are glad

tnx

Uniseat
 
Last edited:
Nov 2, 2004
9,335
0
South Wales
I done this to Forbez car just now in the dark. Took about 5 mins when you know how.

IMO the mod does hardly anything but it does make the engine top look tidier.
 

flooky

Guest
so is removing this a good idea and worth it if the car is std but 007dv? there are mixed reactions about this with peeps running higher boost?
 

fistic

Guest
HEy SIM

could you give me your e-mail ? legyszi, kisse tanacstalan vagyok.
 

fistic

Guest
mabe guys you could help me out.
I bought in December an Octavia RS. 1.8 t AUQ engine. I made about 7.000km with it without problems. Now I have the yellow light. I!ve put a VAGCOM on it and had the following fault codes:
17608 - Boost Pressure Control Valve (N249): Mechanical Malfunction
16795 - Secondary Air injection system - incorrect flow detected
17705 - Turbocharger/throttle valve hose connection - pressure loss

after deleten them thez reapear within 1-2 days, and the yellow light a few days later.
The car is slightly chipped, it is aroun 205 HPs and has a
BOV. Is suppose this problem might be because of the bov or something.

The car is running smooth, eating very few gas there is only on thing that i noticed: in 4th ot 5 th geat after 5500 rotations/ min it becomes to fluctuate the power. It acceleretes and then looses power then accelerating again and agai and again.

Any ideas ?

Could be the N75 whichj is F. Maybe the n249 was not bypassed when they put in the bov ?
 
Apr 12, 2008
539
1
i did a bypass today...took me 20 mins...very simple...and what the difference
DV sound is sooooo much better...its not a gay wwhhoooossshhhhhh anymore...now it is much shorter, louder, better:D
 

Oytun

Guest
problem

problem with deleting n249 @ 2004 LCR 225 BAM

i have no SAI from stock so i dont need to remove it :)

But i Removed N249,

then I connected the hose at top of dv directly to Intake Manifold,

DV is open everytime when idling and releasing boost out when pulling, there is always a vacuum at intake manifold so it opens the dv permanently. i got red spring, and supersize forge dv its strong.
 

nils 6l

Dutch Driver
Aug 9, 2008
61
0
Netherlands
I know a lot of people do this mod, not only from this forum, but I think everywhere and it all started here so I will post my cons here..

To provide a fast BOV reaction you need a good connection with the vacuum source, that's why everybody is getting rid of the N249 and get a direct connection to the inlet.

What a lot of people doesn't know is that the N249 has got more than one function. It does not only gives a smooth turbo build up in a stock car. (if the car is mapped properly and the actual boost is always lower as the boost asked by the ECU the N249 won't smooth anything of at all), but it also provides a very fast BOV reaction.

What a lot of people don't know, is that the N249 also reacts when you go off throttle. As the gas pedal is electric the slightest change is noticed. If you release the pedal for a little bit a signal is send to the N249 and it opens the BOV, even before there is enough vacuum behind the throttle valve in the inlet. So this will provide a faster BOV reaction.

At a Dutch forum there were a lot of people who did not believe me, so I went out to proove this.

I replaced the N249 with an resistance, so the ECU thinks the N249 is still on the car. Over this resistance I put my voltmeter.

P1040680.JPG



First I tested the N249 valve without the engine running, with VCDS to check the reaction of the voltmeter.

http://www.youtube.com/watch?v=-VlMZMuauWE
Every time the N249 is active you see the voltmeter gives about -10V (because the engine is not running).

The multimeter is a very cheap one so it reacts very slow on changes. It's not important how fast the voltmeter reacts though to proove the N249 works when release gas, it only shows that it works.


http://www.youtube.com/watch?v=HOQrvSg_TnM
Running you can see the meter going to about -13V every time I release the gas, so this does prove the N249 provides vacuum when I release gas.

Check here for some more testing video's.

http://www.youtube.com/watch?v=NIZzlWIeRl8
Here's another movie with the N249 connected to the bov. As you can hear it react's very fast.

So if you have a stock car, it could give some advantages removing the N249 because when the turbo builds up pressure it can't be wasted by the N249, but if you're car is mapped properly, and the programmed boost is alway higher as the actual boost, the N249 is there to provide a fast blow off reaction.
 

T211

Guest
Part Numbers

Hi all,
Very informative thread - thanks!
Has anyone got/know the part numbers for the N249 solenoid, check (one-way) valve and the vacuum reservoir please?
I'm looking for just this kind of thing to build a manually switched supercharger bypass system for my Golf.
Thanks in advance.
Toby
 
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