n249 bypass

Deleted member 20376

Guest
Yea, if you need a hand I've got a fair few tools in Lboro these days :)

sweet cheers mate.
tbh i didnt really notice much from mine as my dv was quite loud for a forge 007 anyway hard to say with boost wise without having a boost gauge.
 

bathrumble

Guest
Did mine a while back and it definatly releases quicker now and i think its a better sound and maybe even slightly louder, cant say ive noticed alot of difference driving wise though.
 

SeatR

Active Member
Mar 17, 2008
399
0
Norway, Bergen
Just done this mod.

The dv is very slightly louder but the biggest difference is on part throttle. When i drive down my street on part throttle in first (between speed bumps) the power would cut off. It was as though i had lifted my foot off the throttle but now it hold its speed without the jerk. Its abit hard to explain.

i have this same problem ! its a pain in the ass to drive en 1th. between speed bumps and i look like and idiot who cant drive when the power cuts.

So if this mods helps i would be glad ;D trying it out to night
 

Faisal

UK's 1st Liquid Yello LCR
May 27, 2008
1,445
0
Most likely at work
for me its the reverse..car was smooth before the bypass, afterwards it jerked/stuttered and i couldnt hear the dv loud enough. eventually i thought enough was enough so switched it back. and im glad i did.
 

leon cupra r

Back in an LCR!
Nov 10, 2009
902
0
Barnsley
hmmmmmm

for me its the reverse..car was smooth before the bypass, afterwards it jerked/stuttered and i couldnt hear the dv loud enough. eventually i thought enough was enough so switched it back. and im glad i did.

Ahh thats a bummer, dont know how I'd manage if I couldn't hear my dump valve when I was reversing! :lol: haha!

Anyway,

I just tried this today, and to be honest I'm split as to whether or not I prefer it bypassed....

Dump valve definitely sounds different, although to be honest I don't think it releases any quicker... (I'm presently using very thin vac hose, as unipart only had about 2mm in stock, so this might explain why it is a little delayed in opening) although I see what people mean about the 'crack' sort of sound it makes when dumping, sounds quite nice...

I originally just stuck the whole metre of hose on, and there was a slight bit of turbo chatter when letting off (like half a second of chatter, followed by dump) which you can now barely hear after cutting pipe short... which makes me wonder if the crack sound we can hear is just a combination of a split second of turbo chatter (one or two chambers venting back up the TIP) followed by the DV...

I know that people say the DV should react quicker with all the boomf bypassed, but I do wonder if this is infact the opposite, and with the help of the vacuum reservoir, the N249 actually manages to open the DV quicker? the reservoir acting as a store of extra vacuum to suck the DV open sooner?

Obviously, being a bit of a retard, I have no mechanical back up for this, just a few thoughts going through my head after having a listen tonight....

Views on this anyone?
 

Jenko

Guest
Hello all.I know this may sound dumb but what exactly do I need to do the n249 bypass?I've heard alot of talk about it but don't actually know wat it requires.I've got a mk3 Ibiza cupra and would like to make a few cheapish mods to make it that bit quicker! If anyone could explain I'd b very grateful.thanx
 

jaybeee

[e]
Feb 24, 2006
202
0
Belfast
www.metalrhino.com
This is certainly an interesting thread.

Seems that there's quite a split in opinion/results when doing this mod. Some seem to say it improves things while some say it makes things worse (or could make things worse).

I also always take note of what mechanics and the like say about such things and the Forge guys don't seem keen on it...

I do however wonder if this bypass would "fix" the slight delay in response I get (which many have said it does improve).

For those that have done it, as of June 2010, what are peoples opinion on this now?
 

leon cupra r

Back in an LCR!
Nov 10, 2009
902
0
Barnsley
im still split between which is better....

If you have ever had the problem of coming off then straight back on the throttle and having the DV open for about 2seconds under full throttle... The bypass seems to put a stop to this, which is good and obviously makes the car more responsive... However, when coming off the throttle, it is harder to do it gently for some reason; this combined with the slight bit of turbo chatter you get a split second before the DV opens makes me think the bypass makes the DV slower to respond when it needs to open, possibly causing damage to turbo.... It is also possible to get chatter when coming off the throttle under part acceleration which I never got before the bypass...

I am tempted to put my green spring back in with the bypass to see if this improves that problem....

Dont suppose this has helped you as its by no means an argument for or against! its nice to get rid of the annoying n249 interference, but I am not convinced its good for the car!
 

jaybeee

[e]
Feb 24, 2006
202
0
Belfast
www.metalrhino.com
^^ no mate, that's good info. I see what you're saying and I do think it will help the smoother acceleration, but worry about the throttle release being hasher plus the possible damage to the car/turbo.

I know it's a cheap and easy fix, and my car is ok to have this done since I have a stage 1 remap and a forge 007p.

Anyone else wanna chip in?
 

leon cupra r

Back in an LCR!
Nov 10, 2009
902
0
Barnsley
Just give it a try and see what happens mate, you can always revert back to standard if you dont like it.... I can't see it immediately blowing up your engine to be honest!