n249 removal

[texasboy21]

does anyone have or know of a good write up on the n249 removal on a b6?? i recently did the diode mod and think it will help w the mod.

barrett

[F16HTON]

No need to remove it, just plug the vaccum line coming off of it and run a line straight to the DV off of the intake manifold.

The ECM likes to see it plugged in and manifold pressure.

[Capt. Obvious]

I get all these damn valves mixed up. What's this valve do?

[dougyfresh]

N249 bypass diagram:


Go here for more info: http://forums.audiworld.com/a4/msgs/2437747.phtml
(good info further down in the 'tree)

The N249 is the turbo bypass valve. It works in conjunction with the DV to bypass excess boost.

[Capt. Obvious]

Ah, is that the one that is responsible for the boost coming on so weak/gradually, instead of just letting the turbo go straight to full boost? Is it worth it for us non-BT guys to bypass it?

[dougyfresh]

The AW thread said a bunch of guys (I'm assuming they are non BT) bypassed it and boost seemed to be better. I am going to bypass it after my car is retuned.

[Capt. Obvious]

Hmm, maybe I'll do it too just to see how it feels. I miss the feel of the turbo coming on hard and fast like in my Eclipse as opposed to the slow gradual feel of these cars.

[F16HTON]

Ah, is that the one that is responsible for the boost coming on so weak/gradually, instead of just letting the turbo go straight to full boost? Is it worth it for us non-BT guys to bypass it?

It is a good addition for those with upgraded diverter valves and running higher boost.

[texasboy21]

it will also help with partial throttle boost; thats what im doing it for. stupid question but dose someone have a pic of it..??

barrett

[GarbatyA4]

so we just loop vac lines on the valve?

I've been looking for a spot to run ad irect line for my DV

Thanks guys!

[dougyfresh]

Read post # 4 for pictures

[GarbatyA4]

this should take no longer than 15min to do. Glad I bought 5m of oem cloth braided vacuum line :)

[B6Lovin]

oem line is garbage. lol

high-grade silicone line from home depot ftw

[gq9]

I don't understand, can anyone break down what you are bypassing. It directly connects the line... and then I'm lost.

[old guy]

I don't understand, can anyone break down what you are bypassing. It directly connects the line... and then I'm lost.

Currently the vacuum line goes from the corner of the manifold to the N249. A second line comes from the other side of the n249 and runs to the DV. You need to run the line from the corner of the manifold directly to the DV. Then take a short piece of vacuum hose and connect both ports on the N249 to each other (make a loop).

[rxrep]

Any down sides to this? I'm going to do it tomorrow. Should've done it when I had intake manifold off for painting. Dur.

[A4 TSCHUSS]

You do not have to loop any hose on the N249. Run a hose directly from the manifold to the diverter and that is all. How do I know this? Because I have done it as well as others. I actually reached under my manifold and ripped the hoses off the valves and in the process snapped off all the nipples a hose was on.

[dirtybrd]

If you don't cap it off you'll create a small boost leak.

[A4 TSCHUSS]

There are no hoses going into it anymore.... Stuff is rerouted around and the valve is sitting bare.

[dirtybrd]

You didn't mention removing all the hoses, or I misunderstood.

[A4 TSCHUSS]

I said I ripped out all the hoses and snapped off the nipples on valve in process!

[dirtybrd]

Yes you did, sorry.

[coowhip]

Would my boost guage then be hooked up to the red line there? I'm assuming the little blue loop wouldn't do anything having a boost guage hooked up to it.

[audikid66]

i am interested in doing this too... i like how the boost came on hard wen i bypassed my n75 and did a MBC but i think thats y i blew my k03 so i dont wnna blow my k04 by doing the same.. but this seems like itll work nice so can anyone explain the best way to do this...

[dougyfresh]

I did this yesterday. Simplified my vacuum lines SO much. Now I have a T coming off the intake manifold (where the red line is) and one line going to my DV and the other going to both my EBC and boost gauge.

I left the N249 vacuum connections open to atmosphere but kept the N249 plugged into the ECu harness.

The one connection that ran to the N249 from the Evap system (its a long bridge with a connector to the N112) I rerouted into the N112 (#16 on image, also known as the SAI solenoid valve) so that system is still closed. I did this because the one line coming out of the N112 goes to the SAI Combination Valve (#7 on image) on the back of the cylinder head. That solenoid is gone in my car but the N112 is still present. I had a plug on that vaccuum connection on the N112 so removing that plug and connecting the 'bridge' to it simplified that stuff too. In the future, I will be cleaning up the EVAp system too. Just haven't gotten around to it.

[audikid66]

how long did it take?

[dougyfresh]

how long did it take?

20mins give or take since I know my way around my engine bay, all my vacuum lines are 100% silicon, I don't have any of those factory one-time-use connectors and my DV is up ontop of my TIP (as opposed to the factory position down infront of the TIP near the radiator). I also rerouted the lines for my boost gauge and EBC.

Should take no more than an hour, tops.

[05A$SE]

wont this throw a code?

[audiminiac]

And how does it feel now? Does the boost come faster? How much faster then before ?

[widgget]

yeah, i am very interested in this and want to know exactly how it will change the feel of the car.

[texasboy21]

the boost definitely comes on faster. i have the diode mod and hte partial throttle is a million time better. i say DO IT!!

barrett

[dougyfresh]

wont this throw a code?

As long as the N249 is plugged into the Ecu it will not throw a code. This was mentioned in post 2 of this thread.

And how does it feel now? Does the boost come faster? How much faster then before ?

As long as your DV is hooked up correctly you shouldn't notice an increase in boost building. I did notice the DV is more responsive when I let off the throttle to shift gears (the whole point in doing this).

[widgget]

As long as your DV is hooked up correctly you shouldn't notice an increase in boost building. I did notice the DV is more responsive when I let off the throttle to shift gears (the whole point in doing this).

So I wonder how much of a different this will make on a tiptronic then. I'll play with it once i get my issues all sorted out.

[phantom b6]

Did it just now.. took me literally 10 minutes once I had gone to the store and bought some vacuum line and clamps. My impression is coming from a FWD CVT with 1+ and TIP/DP/Exhaust/FMIC

Before the mod I wouldn't see full boost in 1st + 2nd (using the shifter) and I had assumed it was because they were so short.. Now I see 15psi in first and 20psi in second and 21 in third.

Previously, when I'd do a pull there wasn't that instant torque in the seat feeling because the turbo was spooling and when it spooled you just felt the sensation of going fast. Now, that little bastard spools up fast and you feel that jolt into the seat like I've been missing all along.

[BNZ TOY]

wow, i'm going to do this. I always found it weird that my Bov's response to throttle release to be SLOW. In the Talon, it would be instant, the A4 hesitates a split second before the venting.

NOW I KNOW WHY! Thanks!

Oh, 1 thing. I would imagine this would make Half-Throttle bumpier/rougher???

[phantom b6]

It improves half throttle actually.. I don't know why but you can boost any random number and hold it if you'd like

[texasboy21]

It improves half throttle actually.. I don't know why but you can boost any random number and hold it if you'd like

i second that, its a much better design.

barrett

[audikid66]

ok def doing this now ha

[05A$SE]

anyone having any problems?

[phantom b6]

negative... everything runs good