Did The N249 Bypass Today....

A3 T

A3 T

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I did the bypass today and took loads of pics so if anyone need them let me know ;)

After doing it the i did get a bit of chatter/flutter for the first couple of minutes but i think its sorted itself out now (maybe it only does it when the engine is cold).

It has however made the the dump valve sound a bit different and its also now very quite.


I amplified a sound clip so you can hear it:

 
Last edited by a moderator:
Took the car for a long drive today and there's definitely something a miss....

The dump sound it definitely not as loud and I'm getting the odd flutter (more like an echo).


I'm thinking the reason behind this happening to some people and not others could be to do with the way the boost gauge is tapped into the same place on the manifold that the DV is.


What do you guys think?

Could it be worth putting the T from the DV to the FRP and the boost gauge from the manifold?
 
Nooooooo keep the FPR separate as it can cause overfueling and lead to expensive problems
 
rhubarb4 said:
Nooooooo keep the FPR separate as it can cause overfueling and lead to expensive problems
Click to expand...

Ok mate....lol

Is there anywhere else i could T the gauge into?
 
On mine the AMK engine it has 2 nipples on the manifold so my vac pipe comes off the manni to the DV valve so I can T off that pipe the FPR vac pipe goes straight to the manni to the second nipple, do you have 2 on the AUM.

Chris.
 
rhubarb4 said:
On mine the AMK engine it has 2 nipples on the manifold so my vac pipe comes off the manni to the DV valve so I can T off that pipe the FPR vac pipe goes straight to the manni to the second nipple, do you have 2 on the AUM.

Chris.
Click to expand...



That's how I've got mine mate...

But i think having the sai, dv and the the boost gauge all coming off that one pipe on the manifold is a bit much and the reason I'm getting the slight flutter :(
 
A3 T said:
That's how I've got mine mate...

But i think having the sai, dv and the the boost gauge all coming off that one pipe on the manifold is a bit much and the reason I'm getting the slight flutter :(
Click to expand...

There was a write up about this somewhere just trying to remember what was said, I'm sure there was something that stops the boost gauge from fluttering it may have been a type of gauge I think it was on Awesome's web site
 
I just had a quick look its not what I thought it was its a No Buzz restrictor T fitting, which I dont think is what the problem is

Chris.
 
rhubarb4 said:
There was a write up about this somewhere just trying to remember what was said, I'm sure there was something that stops the boost gauge from fluttering it may have been a type of gauge I think it was on Awesome's web site
Click to expand...

Thanks mate, but its not the boost gauge that's fluttering its the DV.

I've actually got one those restricted T pieces but changed it to a normal one when doing the bypass. Since changing it though my gauge doesn't move as smooth so ill be putting the old one back on.

It there anywhere else I can T the gauge off apart from the two ports on the manifold ?
 
Not as far as I know im sure thats the only place, unless Welly or Tuffty know another way try PM either of them.
 
rhubarb4 said:
Not as far as I know im sure thats the only place, unless Welly or Tuffty know another way try PM either of them.
Click to expand...


Ok thanks ;)

Do you know if the ports on the manifold lead to the same place?

What i mean by this is, could you put the hose from the fpr to the port that the dv is on (and vice versa).
 
Looking at it the just exit pipes so I cant see why not, there too close together to be separated by anything inside.
 
Thanks again ;)

I think I'm going to disconnect my boost gauge and see if that mate any difference.

Other than that, has anyone else got any ideas why i would be getting the flutter?
 
If you are getting flutter then you haven't connected the DV correctly and its not seeing a vacuum... N249 bypass should consist of a simple vac pipe stright from the mani to the DV... I have seen some people refit check valves which hold the DV shut or open depending which way they fit it... it does not need a check valve...

<tuffty/>
 
audi upgrades
<tuffty/> said:
If you are getting flutter then you haven't connected the DV correctly and its not seeing a vacuum... N249 bypass should consist of a simple vac pipe stright from the mani to the DV... I have seen some people refit check valves which hold the DV shut or open depending which way they fit it... it does not need a check valve...

<tuffty/>
Click to expand...



What check valve mate?

This is how I've done it:

img2011090100369edit.jpg


img2011090100370.jpg



I've then put a T at the Dv to go to the boost gauge.

The boost gauge is still saying I'm getting good boost.


Does this look like i have done the bypass correct?
 
Erm... no not really... N249 bypass doesn't use a valve at all... pipe direct from inlet manifold to DV... its that simple... just need to leave the valve electrically connected to keep the ECU happy

<tuffty/>
 
...actually... it looks like the DV should work... never done a bypass like that before though... non of the valves end up with pipes in them on the ones I have seen done...

<tuffty/>
 
Also shouldn't the DV psssssst be a bit louder with the bypass?

Mine doesn't sound as loud as it did before the bypass :banghead:
 
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I wish I could help you mate :( but for me and most its just 1 pipe, that is all thats needed. You should hear the dv working/reacting a little faster, so essentially less tssshhhhhhh, and morr tsshh. Lol
 
superkarl said:
I wish I could help you mate :( but for me and most its just 1 pipe, that is all thats needed.
Click to expand...

:(

Is it because I have the aum engine that I've got to do the bypass how I've done it ?
 
ive done one on an amk and one on my auq and both were just the one pipe as neither had the SAI. maybe if u have the time u can follow the sticky on here and do the SAI removal. im not sure if this will solve ur problem but is another thing to try. my dump valve has always fluttered like **** (i think its broken a bit)
 
audi upgrades
A3 T said:
:(

Is it because I have the aum engine that I've got to do the bypass how I've done it ?
Click to expand...

The reason you have had to do it the way you have is because you have SAI and you are keeping the SAI. From your annotated pic it looks like you have done it correctly
 
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I did a bit experimenting this morning.....


If I'm in 1st or 2nd i don't get any flutter what's so ever (low boost or revving the tits of it) but the psssst sound is still very low compared to how it was before i did the bypass.

As soon as i go into 3rd and up , the flutter starts at either hardly any boost all the way up to full boost.



Any ideas ?
 
it has something to do with the boost guage tap in as i did mine fluttered tried all sorts of ways round it nothing changed it back was fine so ive just changed all the pipes for silicone ones to avoid any splits and to be fair there was hardly any gain from it also the dv sounded worse then it did before.

imo i would just change the pipes to silicone and put it back the way it was if it fluttering, bill from badger 5 had a look at my diagram and how i done it and was all linked up correct. changed it back with silicone pipes and all is fine.
 
So was everything ok when you disconnected the boost gauge mate ?
 
it worked a bit better getting the odd flutter here and there but for what its worth i wouldnt bother with the mod just change the pipes for silicone m8 as when i connected the dv back in fluttered like mad again tried all sorts of tee-pieces to try and stop it metal,copper, antibuzz, normal plastic. tried moving the tee next to the dv no difference its although having the boost guage is reducing the preassure to open and close the dv from the manifold making the dv flutter
 
I rally would like to sort it out rather than putting it back as the car feels a lot better with it bypassed.

Was your flutter really bad then ?

Did you try putting the T in the FPR instead of the manifold to test it?
 
keep ther vac line short to the Dv, no other long tails hanging off it.... as that will delay the overall vacuum being pulled... air is compressable and stretchy, so more pipe, expect more delays in it working.

Plumb direct to DV off manifold. keep it simples and short and in decent size pipe (4mm I think from memory)
 
A3 T said:
I rally would like to sort it out rather than putting it back as the car feels a lot better with it bypassed.

Was your flutter really bad then ?

Did you try putting the T in the FPR instead of the manifold to test it?
Click to expand...

yeh flutter was rearly bad sounded like a subaru with flutter bov
 
badger5 said:
Plumb direct to DV off manifold. keep it simples and short and in decent size pipe (4mm I think from memory)
Click to expand...

I'm using 4mm hose mate ;)

How can i plumb the DV directly (one hose) without putting a T in for the N112 (i think that's what its called) ?


Syvo said:
yeh flutter was rearly bad sounded like a subaru with flutter bov
Click to expand...


Mines not that bad...lol

Did you try and T into the fpr?



I removed the T for the boost gauge today to give the DV a bit of extra pressure but it made no difference what's so ever :(

What i find strange is that you would think by removing the N249 and coming off the manifold , that there would be loads more pressure for the DV and the ptsssst would be louder (if not the same as before the bypass).
 
I've spent the last few hours looking all over the net for a solution but there doesn't seem to be any hope :(
 
Just had another idea.....lol

Would it work if i linked the N112 in to the FPR then run the DV straight to the manifold ?
 
technically it would work, but then so should you current set up. If you were to do it like this you would have to be careful that there were no boost leaks in the FPR line
 
Alex C said:
If you were to do it like this you would have to be careful that there were no boost leaks in the FPR line
Click to expand...

That's what's worrying me mate :(

I was thinking of putting the T in the FPR for the DV but I'm thinking, If the pressure from the manifold is that low then it will mess with the FPR every time DV dumps.
 
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