Audi S3 8L N249 valve bypass - how to?

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Luciano

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Hi,
Could someone help me bypass the N249 valve on an Audi S3, year 2001, 1.8T, 210 HP quattro, AMK engine?
Bellow there`s a picture of the engine with the valve. Please explain, if possible using the picture, what do I have to do, witch hoses do I have to move. I've searched the web, but I haven't found a guide for this specific engine.
Thank you!

n249valve1.jpg
 
Disconnect the hose from the divertor valve nr rip out all the crap. leave the N249 connected with no hoses on and hide it down by the coil packs then just run a new hose from the bottom of the inlet manifold to the divertor valve
 
What is the reason for doing this?
 
and also eliminates the potential one million leaks you can get with the n249
 
So does everyone do this and is it worthwhile?
 
audi upgrades
If you do a search I posted up some VAGCOM results where i was holding another 2 pound of boost due to this mod. I did before and after logs and it is definitely worth it. It also sharpens up the throttle response quite a bit.
 
i did it because i couldnt be ***** to go over the n279 mess and check for leaks, and i could tell it gave the ECU control over my fun, started to rave about it on the board and it turns out everyone does it haha
 
Is the N279 the gubbins that monitors air on cold start? Because if so I'm ripping this **** out as well.
 
i think youre thinking about the secondary air doo dah
 
N249 bypass definitely helped on mine. DV noise got alot louder too but that's with my BMC kit aswell.
 
does it put extra strain on the turbo though? surely they wouldnt put the n249 in for no reason
 
audi upgrades
Did anyone actually read the link I posted above?

It wont put any extra strain on the turbo as this mod doesn't increase boost. The N249 valve is controlled by the ECU and uses pressure stored in the vac reservoir (Black Box in the pic above) to open the DV if necessary as an engine safty feature. Reasons for the ECU to open the DV are:

- Triggering of traction control. If you've got ESP and you've really tried to beans it through a roundabout in the wet you'll know what I mean. The ECU detects you're well out of shape, opens the DV and you feel the power and car bog down, nasty!

- Boost spikes. The ECU can detect a spike or surge of boost and will open the DV to protect the engine but at the end of the day there are other devices in place to detect issues, such as ignition retardment, so nothing to worry about.

In summary all old turbo cars with a DV opperate in this way (without the N249) and Audi just stuck the N249 syste on as an extra safety feature as they were releasing a 210/225 hatchback that would be driven by old ladies and mums doing the shopping.
 
And where would the N112 valve be located on the engine from the first post picture? Under the vacum chamber? Because, if I got in right, I have to use the T piece, the right side goes to the BOV and the left one to the N112. Am I getting it right?
 
Last edited:
Luciano said:
And where would the N112 valve be located on the engine from the first post picture? Under the vacum chamber? Because, if I got in right, I have to use the T piece, the right side goes to the BOV and the left one to the N112. Am I getting it right?
Click to expand...

The N112 isn't in that pic, its underneath the plastic panel that holds the dipstick tube. You might not have the N112 valve as they weren't on the newer engines. Mine's a BAM and they didn't have them.

So if you dont have the N112 all you need to do is use a 3/4mm joiner or get a new piece of silicone hose and plum together the DV hose to the one that goes to the front nipple of the inlet manifold, done.
 
IIRC, your engine is AMK? and so doesnt have secondary air injection? So also doesent have the N112??
 
Thanks, l got a APY in mine! l keep reading about AMK,BAM, l thought l got the wrong engine in the old girl(2000 S3).

Good luck in the world cup Stig.
 
Job done! It's true that my AMK engine doesn't have the N112 valve, so I' simply conected a 4mm silicon hose from the intake manifold to teh BOV. I left the N249 valve electricaly conected and...that's it!

non249.jpg
 
what inside diameter silicon hose did you use mate and where did you get it? is it worth doing?
 
3mm id has always made a perfect seal on a vac nipple ime
 
Sorry for another question.

Can i bypass this one mine. It's engine code AJQ ?
 
Thanks luciano, im doing this now >>>>> runs off to do this now lol
 
i just attempted this and ended up snapping the nipple under the manifold

please please when doing this bypass, use a straight connector piece or something if you cant take the hose clamp off the manifold nipple, i wish i thought of that, now im stuck (see my post)
 
Just for clarification which is the better route to go down then 3 or 4mm id tubing?

Edit: How much tubing is required roughly if replacing it all?
 
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Sweet cheers guys, for the sake of a tenner figured might as well replace all the tired old hoses.
 
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