# n249 delete crew



## ViperOneZero (Sep 4, 2008)

I just joined it. I must say that on my car this "mod" has made a definite improvement. Acceleration is nice and smooth.... took 10 mins to complete the mod... very easy do do.. Gunner Spanner Rating - 1 spanner ( piece of Pi$$)


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## jamman (May 6, 2002)

How about a gunner how to ?


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## medlen1985 (Apr 9, 2010)

jamman said:


> How about a gunner how to ?


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## ViperOneZero (Sep 4, 2008)

to be honest there is a wealth of guides... the guides on this forum make the job look more difficult than it really is.

however a few links to assist :

good BAM engine guides:
http://www.seatcupra.net/forums/showthread.php?t=215866

http://www.audiforums.com/forum/showthread.php?t=122414


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## alun (Aug 2, 2010)

welcome to the crew.


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## Soton (Jan 15, 2011)

welcome!

Did you notice an increase in DV noise?


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## ViperOneZero (Sep 4, 2008)

yes...


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## colingo (Sep 19, 2009)

Would there be any noticiable benefit in this n249 delete on a none remapped 180hp quattro car. Colin


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## tonksy26 (Jan 31, 2011)

You fancy doing this to mine aswell  haha

Does it damage the engine at all ? Even in the long run ?


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## kazinak (Mar 23, 2010)

tonksy26 said:


> You fancy doing this to mine aswell  haha
> 
> Does it damage the engine at all ? Even in the long run ?


no

done it ~6 monts ago due to boost leak, it was easyer to remove it then fix the leak :lol:


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## Stub (Mar 17, 2005)

Had mine done for over 2 years and all fine, had a hesitation before and this cured, also nice noise created, I thought it was wastgate chuff but looks like it's DV, o also looks cleaner under the hood


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## dankay1989 (Mar 23, 2010)

gonna have a go at this when i get my car back tuesday, does anyone have links to the parts i need cheers dan


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## alun (Aug 2, 2010)

its more a case of what parts you dont need. :lol:


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## Charlie (Dec 15, 2006)

Before anyone does this, I suggest they do their research. Wak does not recommend doing this as you are effectively removing a safety control :? and for me if Wak doesn't think it is a good idea, then I am not doing it 

Charlie


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## ViperOneZero (Sep 4, 2008)

Charlie check the Seat link at the start of the thread. Some benefits there.. Its a common mod which is frequently carried out by VAG users across the board..

Many have seen benefits... including me... and plus there is no spaghetti junction on your rocker cover.


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## ViperOneZero (Sep 4, 2008)

dankay1989 said:


> gonna have a go at this when i get my car back tuesday, does anyone have links to the parts i need cheers dan


4mm silicone tubing
Zip ties /tie wraps
scissors
10mm spanner

check the links in my second(ish) post on this thread for how to. There are also a few on this forum.


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## dankay1989 (Mar 23, 2010)

from reading....dont i need some sort of resistor and t piece??


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## ViperOneZero (Sep 4, 2008)

dankay1989 said:


> from reading....dont i need some sort of resistor and t piece??


deends what sort of level you want to go to..
there are 2 stages to the mod.. you can either leave the n249 valve connected up to the loom socket to prevent ecu fault probs / rough running, or you can completely remove the 249 valve, cut the connect socket off and solder the 2 wires to a resistor to fool the ecu that everything is running smoothly.

I have carried out stage 1, but I have the resistor bits to fully remove the valve.. when it stops raining i will solder it on, and neatly took it away.

t piece only needed if you decide to fit a boost gauge.

330 Ohm 10 Watt resistor- http://cgi.ebay.co.uk/330-OHM-J-R-1...CarParts_SM&hash=item19c40388ac#ht_795wt_1144


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## alun (Aug 2, 2010)

its the valve thing your talking about.. i just taped it up.










and then ran a vacuum tube down the side from dv to under the manifold


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## KimTT (Jul 12, 2009)

Hmmmmmm thinking about going this a go...


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## kazinak (Mar 23, 2010)

GunnerGibson said:


> dankay1989 said:
> 
> 
> > from reading....dont i need some sort of resistor and t piece??
> ...


i have geting fault code on wagcom,when it was resistor 330omh 10w,( i think it was ''circuit short to plus''),now i have relocated valve near coolant botle


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## chippen (Mar 15, 2011)

Hi,
you guys sound like you know your stuff... 
I read somewhere that the n249 valve was only fitted in cars from 2000 and on. Can anyone confirm that? My AJQ engine was built in oct -99 (MY 2000) so am I right to think that there is no n249 valve in my car?


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## alun (Aug 2, 2010)

> you guys sound like you know your stuff..


see... thats your first mistake. :lol: :lol:


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## lazerjules (Apr 18, 2009)

I just had to do this, but not intentionally. I just discovered the manifold connection of the T piece joiner had become brittle and snapped. I have temporarily had to join DV hose and manifold hose until I get a new T.

Be interesting to see how it goes.


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## Gerry-TT (Jan 27, 2009)

I second Charlie

Wak and Morgan do a lot of r and d

If they don't see gains of doing something then they won't recommend it.

But its your cars so go ahead and try it.

I won't.


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## tonksy26 (Jan 31, 2011)

Gerry-TT said:


> I second Charlie
> 
> Wak and Morgan do a lot of r and d
> 
> ...


Why do they not recommend doing it though ?


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## Charlie (Dec 15, 2006)

Charlie said:


> Wak does not recommend doing this as *you are effectively removing a safety control* :? and for me if Wak doesn't think it is a good idea, then I am not doing it
> 
> Charlie


As above highlighted from earlier in this thread buddy 

Charlie


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## ViperOneZero (Sep 4, 2008)

below is a post from one of our Cupra 1.8t friends. This should help you decide... ( original link here 11 pages of debate )
http://www.seatcupra.net/forums/showthread.php?t=42406

N249 is controlling the DV (Dump Valve). It is installed between the intake vacuum source and DV itself. When no current is switched to the N249 (default state), the DV will get vacuum or boost from the intake manifold. This is how almost ALL turbo cars are worknig. When shifting gears, you let off throttle, TB closes and vacuum is generated which can open DV to vent boost (which cannot enter engine, because TB is closed).

On never 1.8Ts (2000+) they introduced the N249 (along with lots of other stuff) which is a possibility for the ECU to open the DV any time (!), even during full throttle/acceleration. When the engine is running and turbo is boosting, there is no vacuum generated, but to open the DV (which is mechanical), vacuum is needed. This is what the black vacuum reservior on top of the engine is used for. When idling, shifting, etc - so when vacuum is available, vacuum is led into this reservoir from the intake manifold and kept inside using a check valve (white/black), so when boosting again, vacuum will stay there (air cannot enter into the reservoir).

When ECU wants to open DV durnig full throttle/acceleration, simply "energizes" N249, which will "de-select" the DV from the intake manifold (boost), and "switches" it onto the vacuum reservior. The vacuum in the reservoir will open the DV instantly and release your boost, which, in most of the cases (tuning, etc) is not that highly required . In the case ECU sees a little overboost problem, it can turn N249 on/off repeatedly for very fast (just as N75 is working), which will open/close DV all the time, trying to settle (lower) the boost level.

PROs: By removing N249 valve, you can prevent this bad habit of the ECU, and by removing N249 valve, you are removing an approximately 2mm narrow bottle neck restriction (ID of the N249 valve) in the line to the DV, which will result in a somewhat faster DV response. I am using the stock bosch DV, but it feels just as good as an aftermarket DV with N249 (restriction) inline. Boost curve is smooth and progressive.

CONs: Boost overshots/spikes may grow higher, especially in high gear/low rpm situations (using the small K03), which can result in a leaner condition (for the moment). These spikes depend on N75 type, wastegate setting and software programming, but they usually don't last long (0.5-1s max). In the case these spikes are very high (car enters limp even), minor adjustment on the wastegate can be done. Ibiza engine covers cannot be used anymore (by removing the accessories above, two mounting points of the cover are removed aswell).

Shopping List (what you need):

- Some (50-80cm) 4mm ID vacuum line.
- 1x 4mm T piece
- 4mm Check Valve which can be reused from the original OEM setup
- 9 x 270Ohms 5W Resistors (the bigger surface the better)
- Small test/breadboard
- 1m wire (2core)
- Zip ties (big & small), masking tape
- Drilling machine, 1mm thick alu plate
- Soldering ability/skill

This is (below) how the original vacuum reservior, N112 (Secondary Air Injection Solendoid) and N249 (Turbocharger Bypass Valve) looks like on the Mk3 Ibiza 20VT. The entire "system" has been removed, but some part of this has to be reused! I've just simply cut the vacuum lines, disconnected electrical plugs, and unscrewed screws.










As the first step, we have to put the N112 back as this controls the combi valve, which opens the head for the Secondary Air Pump to be able to pump air into the exhaust. The combi valve is operating with vacuum (just as the DV), and N112 opens it (to the command of ECU) during cold starts only. We want to keep this feature (as it has nothing to do with performance) so we have to put the N112 back to its original place. Get it out from the original setup. An appropriate sized alu plate has to be cut, bent and drilled, which is then secured on the valve cover using the screws which was holding the original stuff (seen above). I had to use some washers too, because the screws were a bit long (one screw was taken out from the original assembly, too - you'll see). The Sec Air Solendoid (N112) is secured on this alu plate with 2 bigger zip ties. To hook up the N112, connect the combi valve line (with the silvery heat shield) on top - just as it was connected defaultly. Leave the gray plastic cap on the left side on. That port is used to release vacuum from the combi valve (closing it), so do not clog it. The cap is just used to prevent bigger dirt particles to enter into the N112 & combi valve, when vacuum is "released". Now that two ports are connected (cap & combi valve), you have to connect the vacuum source to the third (horizontal, right side) port. It is absolutely critical that no boost can enter the N112, so place a check valve (salvaged from the original setup) in the right direction (you can suck air out from it, but cannot blow into) before the solendoid (just as on the picture below). Plug the N112 electrical connector in, too. If you are ready, all 3 ports of N112 will be connected, one still unhooked, with a check valve on it.

Now hook the DV up, just lead some 4mm vacuum hose from the topmost nipple of the DV to the valve cover, OR just simply reuse the original DV line. Use the T piece to connect the unhooked N112 vacuum line (with the check valve on) and the line from DV with the vacuum/boost source from the manifold. Zip tie every connections/lines, so they can't move, can't be blown.

This is how it should look like (except for the N249 plug):










Theoretically you have now removed the N249 valve (N112 has been reinstalled, remember?), you could try the car, BUT the electrical plug of N249 is not connected, since there is no N249 anymore. The ECU would detect this fault and the Check Engine Light would illuminate. You have to trick the ECU, so it thinks there still is an N249 valve connected.

To do this, i have measured the resistance of the N249 valve, which is 30Ohms. If you plug anything on the N249's electrical connector which has 30Ohms resistance, ECU would think there's a solendoid there (how silly ). The resistance is just one parameter, there is an other very important one, the load. On 14V, a 30Ohms "thing" will flow nearly 0.5A through. If you would lead 0.5A through a small 30Ohms resistor it would immediately overheat, even burn your hand and things near to it. Therefore, you have to buy a big surface, big load (40-50W) 30Ohms resistor, OR use more resistors, so the surface will be big enough to be able to dissipate heat. I have connected 9 pieces of cheap 270Ohms 5W resistors paralelly on a breadboard and used this "resistor bank" as a 30Ohms 45W resistor. Sadly i have no picture of this, but the formula is very simple. The resulting resistance will be Resistance/Nr of resistors used. For example i've used 9x270 5W which will be equal to 270/9 = 30Ohms 5*9= 45W. It is quite big and oversized so it will not burn anything, it just gets nice warm (30-40C). You may use any setup, but be sure not to use less than ~30W, and make sure it has got a resistance of 30-33Ohms.

This is one of the the cheap resistors i've used. Bought 10pieces for ~1 EUR, this one i have left. They were just simply connected paralelly (NOT SERIALLY!) on a breadboard cut to the right size. A long wire has been soldered on the two ends of this resistor bank and all this has been covered with black masking tape










The resistor bank is then secured to a loom in the car i've found and is hidden, so it is not visible to the unaided eye at all.

I did not cut the original N249 electrical plug off the stock loom (and i suggest this for you too). I've just naked some wire on the other end of the resistor cable, applied some tin on it with the soldering iron, so it got hard and stiff. I could plug these hard wires into the stock N249 plug, and secured them with masking tape well. Be careful and make sure they won't/can't come out and touch themselves! This solution seems to work well for me and it costs nothing.

Practically you have now completed the task! I have got this setup working now on my car for almost 2 months without any problem. Have Fun!

Questions?

Oh yeah, as with anything else, no responsibilities taken!

REMARK: This writeup (as you've probably noticed) was carried out on an Ibiza. The vacuum reservoir, N112, N249 on Leons are located elsewhere, but they look and work the same, so you probably can find them .


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## Rosso TT (Dec 25, 2010)

I think there's a bit more into it than just vent off exess boost.
I was aptenting on doing this to my car and a noticed that the resistor i fitted ( 27W 10 ohm) got very warm on idling so that made me realize that the valve is there also to speed up the DV operation.
I think i read that somewere too.
I then reinstalled it.


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## anthony_m (Aug 28, 2008)

hi,
just to confirm what some have asked, mine is a 1999 [APX engine] and it does indeed have an N249 valve fitted, so i think you can safely say that all MK1 audi TT's with APX or BAM engines have the N249 valve fitted.
hope this helps.
Anthony.


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## 129CBRider (Jan 21, 2014)

I did this to my 2001 AMU engine and now it runs perfect.


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## brian1978 (Jul 10, 2013)

You have essential just bypassed it and added MORE guff to the already cluttered mess. Be as well delete it.


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