N249 bypass issues...

[Benj225]

Hello all

After reading many posts about people doing an N249 bypass i thought i'd give it a go yesterday.

all went smoothly but is there any chance that doing this will actually slow my car down? I'm not sure if its just me but it feels slightly less powerful than it did with the N249? I dont know whether it has something to do with ta smoother power curve but its making me consider reconnecting it again!

Any ideas??

NB. I have a Leon Cupra R 225

 

[paul-murphys]

i had same problem, put mine back to normal an feels better now. boost did come in earlier but just didnt feel as quick.

 

[Benj225]

do you think it is actually a bit slower with it bypassed or just in our minds??

Has anyone timed acceleration etc??

 

[LEE69]

I got about 1 psi more tbh god knows how

 

[Benj225]

Hmm strange, i wonder whether it has anything to do with that fact your's isnt an 'R' ?

 

[andymac]

ive done it on my R' and it didn't make it any slower in fact it felt more pokey

 

[ben652]

mine feel like a rocket on take off

 

[J0N]

I'm really not convinced about this mod, can't help thinking the N249 is there for a reason.

 

[Benj225]

I also dont understand why its now created a little turbo chatter. I've got the split-r valve (and never had a problem with it!) and it never created ant turbo chatter at all, just a nice whoosh. But now i've bypassed the N249 every now and then theres a little chatter. DV does sound different and very nice, but surely the only reason it would chatter is due to a decrease in boost pressure?

 

[speedsix]

There was a guy making posts on some of the N249 threads stating that the N249 is actually used coming off throttle to open the DV quicker than the manifold vacuum, based off throttle pedal inputs.

 

[Ronin225]

I have an R and my boost raised doing this mod by 1-2psi
Car drives fine and had no issues or faults from it

 

[paul-murphys]

if anything mine was boosting an peaking at 21 an holding at 20 without the n249 mod an with the mod would only boost to 20 an hold a little under, boost did come in earlier but sometimes would put foot down an was a little hesitant, its ok now that put my car back to normal,

 

[lordgibbness]

It's definately there for a reason, although it doesn't mean that reason is strong enough to make it a bad idea to do the bypass. However, I always believe "if it ain't broke don't fix it" with most things. My car runs like a peach so doing this mod for no apparent reason just doesn't make sense to me. If I was having hesitation/boost problems I might try it out otherwise can't see the point. Mods I've done so far have only been done if they make road driving a better experience, rather than doing it just cos some other people on a forum did the same thing...

 

[Benj225]

The boost does feel smoother after doing the bypass and it seems to tail off less, but there seem to be the same amount of pro's and con's which result in it almost being pointless. I just find it strange that it can vary so much from car to car...

 

[mrwookie]

N249 is the for safety reasons to open the DV regardless of the throtle position if the ECU tells it so.

By passing it you are using the vac from the inlet manifold to control the DV and haven't got to wait for the pressure in the N249 pipes to pressurize/depressurize so hence the car feels more responsive.

Just to bear in mind regardless of whether you have bypassed the N249 or not the ECU would throw the car into limp mode to protect against any problems so bypassing is not removing all protection per say.

If you are saying Benj225 that you are getting turbo chatter that would point towards a vac leak some where or a knackered DV as its showing the DV is not responding as it should so boost being pushed back when throttle body shuts and the flutter noise is the air hitting the turbo and causing it to stall.

Hope this helps.

 

[Hilla LCR]

Ben, (I'm almost certain your Ben Bray!!)

Have you got your Split-R set up properly, I.e. set soft enough?

Still gotta take you for a proper run in my car!

Alex, your colleague

 

[Benj225]

I was wondering how long it would take before you'd pop up on this thread!

Yeah before i did the bypass i didnt get any chatter at all, but since I have i've started to occasioanlly get a little. Not very much though, but im still going to set it a little softer later.

I have to admit i am beginning to notice an improvement with the bypass but could all be in my imagination!

 

[Hilla LCR]

I defiantely noticed a difference, and mine chatters a tiny bit at low revs, but dumps properly at anything higher than 2.5K

Got Revo put on last night....bloody hell it's quick now!

 

[Benj225]

Getting mine done soon too, cant wait!

You notice a lot of difference then??

In any shape or form turbo chatters a bad thing wouldnt you say?

 

[Hilla LCR]

Hmm don't know all that about the chatter to be fair, but I thought at very low revs, chatter isn't dangerous?

If it's chattering on full boost (which mine doesn't) then I'd think there was a problem?