N249 Bypass

[morf101]

Hello, I am a complete novice to all car work so ask really stupid question learn about it then attempt it myself. So far this has work ok, with most recently changing coil packs and Iridium Plugs ok simple stuff but need to start somewhere and its saving me money to pay for the petrol to run her lol
I have been looking in to the N249 bypass, Firstly is it worth doing Secondly what exactly does it do? Told you stupid question
Thanks

 

[dazjstuart]

No such thing as a stupid question! Someone else will be better qualified to tell you what the N75 actually is, its basically a vaccum reservoir, why you would want this I dont know but it introduces a bit of lag in the dump valve. If you remove it you may find that throttle response is a bit sharper and that you can hold boost longer, N249 has a habit of opening the DV whenever it feels like it. If you have an open cone filter too I believe the DV sounds a bit louder after bypassing the N249

Basically you wont see huge performance increases but as its really easy mod to do I would just go for it. I did it at the weekend it literally takes 10 - 15 mins, some silcone hose, a t-piece and some cable ties. There are loads of how to's on here just make sure you get the one for your engine, mine is an LC 180 AUQ engine but I think the N249 bypass is a bit different for the LCR (AMK or BAM engines) I could be wrong though!

 

[sami1]

I want to do this now. Is this why when i am driving and holding rev's at about 2-3k, it feels like the boost that has been building it releases itself?

 

[ibizacuprabates]

I ant impressed with the 249 bypass, i actualy lost a bit of boost. Im back to normal now and its much better. If u search this subject there are lots if ppl with the same prob

 

[nd-photo.nl]

I like the n249 bypass, boost buildsup faster and is released in a more "spikey" manner (due to the direct vacuum), using the n249 gives you a "smoother" experience. Also, using the n249 should give you a slightly better fuel economy, but I think the weight of your right foot is more important

@sami1
Check below links, click Easy way. 10 minute job if not less.

Check:
Hard way (but better): http://www.seatcupra.net/forums/showthread.php?t=312083
Easy way: http://www.seatcupra.net/forums/showthread.php?t=349627

 

[sami1]

looks fairly straight forward. Just need some tools and parts.

There's so much that can be done to these cars, it's all about having the cashflow and then deciding where the limit is!

Need start saving for some mods!

 

[ozaudio]

is it basicly this?

 

[halsall1987]

If you follow the original hose from the FPR (#2 on the picture) it goes under the manifold.

Ignoring the red hose in the picture above.... the blue line is correct, you just need another bit of hose going from the plastic t-piece under the manifold to where the original hose from the FPR went.

 

[virdi]

The N249 is controlled by the ECU right? So it has a purpose, as it must be feeding the ECU a signal or rather the ECU is telling it what to do.....

Doesn't make sense to remove it.? (unless it has a fault)

 

[paradigm]

The N249 is controlled by the ECU right? So it has a purpose, as it must be feeding the ECU a signal or rather the ECU is telling it what to do.....

Doesn't make sense to remove it.? (unless it has a fault)

It makes perfect sense to remove it if you are making more than standard boost. Less of a reason if you aren't.

 

[mty12345]

As far as i understand it( i'm no expert) the N249 has a few purposes
1. It gives the ECU the ability to open the DV to slightly improve MPG during light load crusing conditions
2. It's a failsafe that gives ability for the DV to open immediately if the ECU detects a problem such as faliure of the N75 valve
3. it should in theory improve the responsiveness of the DV by using the vacuum in the reservior to open the DV slightly before it could be opened by manifold vacuum.

Could be more purposes too but thats the ones i know of, None of them are "vital" for the car, so it's upto you if you want to remove it or not
I'm keeping mine connected but like i say it's your engine, your choice tbh

P.s i think the little louder DV noise which some people report with it removed is actually more likely to be the onset of compressor surge due to the DV not opening so quickly without the N249 connected (not a good thing)

 

[traumapat]

The N249 is controlled by the ECU right? So it has a purpose, as it must be feeding the ECU a signal or rather the ECU is telling it what to do.....

Doesn't make sense to remove it.? (unless it has a fault)

Have to say I agree. If Im happy for the ecu to manage boost and fuelling etc, why not the dv.
Its never caused me any bother and Id rather not remove any failsafe for the sake of it.

 

[morf101]

Thanks for the info... im looking at changing the hoses to silcon hoses soon so will give the bypass ago at the same time

 

[nd-photo.nl]

If you try the easy method, you can always revert. GL+hf

 

[Derekm2104]

As above. I'd give the easy a go and see how it feels first.

 

[mcdatkyid]

Tbf I switch between bypass and standard every so often just for those days when you feel the need for a bit more fun

 

[nd-photo.nl]

I have done the n249/n112 delete and am happy I did, looks much cleaner under the bonnet now and car is less prone to errors due to removal of those systems.