N249 To by-pass or not to by-pass (That is the Question).

[J0N]

What is the intended use fot the N249 and is it really worth doing the by-pass.
I'm not convinced this is a good idea, I tried this mod but only for a quick run somewhere and back and if anything I had less boost and a bit of waste gate chatter. Is the N249 not there for a reason? What are the pro's and con's?

 

[slim20vt]

its has a few jobs to do! but your better offdoing a search try typing in n429 bypass in the search there a few threads on this. including my own thread.

but the simple answer is yes it does work
it helps maintain boost pressure. and stops it from dropping off.

one thing the by pass does is . when traction control is on,it stops the judder or stall feel when the wheels spin pulling away. (stops the dip in power) keeps the boost higher.

must dash. do a search mate cheers

 

[J0N]

Dunno, the way I see it the N249 is a fail-safe to prevent your turbo from over boosting if there is a problem with perhaps your wastegate actuator or DV. This could surely save a blown head gasket or some other disaster. I know lots of people love this mod and it may never, ever become a problem but I've tried it, albeit for a short length of time and I really don't think it makes much of a difference to the performance of my car. I think I'd rather have the protection that the N249 is there for. I know pre 2000 cars did'nt have one so why did they consider it necessary on newer models?

 

[Taylor c]

Well yeah the valve is there so when ya traction kits in restricting power there is no longer any use for all the boost the turbo has created so it releases the excess boost not needed. Coz if ya look at the valve there is a black resivoir box behind it where the excess boost is sent to for release. By passin the valve just causes the boost 2 not be released out the system and kept in the system instead causing the car 2 boost slighty higher and meant to give a better throttle response.

Ya will find mixed opinions and some av reverted to re-connectin it but not sure why and i tried it out and didnt feel all tht different but did feel slightly better throttle response and more of a release noise by induction kit but maybe the more noise made it feel faster lol. I av put it back on now though coz like u said its there for a reason and at the end of the day if it wasnt meant to be there then it wouldnt be and a little cheap mod like tht cant surely give ya all that much more performance.

 

[J0N]

The black reservoir box holds a vacuum to open the DV if the ECU tells it to.

 

[Pabs]

if it aint broke..... don't fix it.

 

[Havok316]

I done mine today, and I must say it has made quite a bit of difference, especially in the lower gears and acceleration is more responsive. does anyone know which resistor you can jam into the sensor? or just leave the n249 connected?

 

[slim20vt]

had a problem with a boost hose today............ it had split and put me in run home made....

so i took my n429 by pass back to standard while i was trying to locate the fault.....
found a split hose on the back of acuator... repaired it... gave it a 2mile spin without the n429 by pass.. everything was fine......
But the lcr didnt feel like it was pulling threw the gears that strong..... and the d/v wsnt as loud...

so got back home and performed the n429 by pass again, took only 10mins...

then went for the same 2 mile spin again what a diffrence it made d/v was alot louder and more fearece. and boost level peaked 2psi higher than with out...


so the moral of the story is DO the blooody bypass its so worth it.................

cheers

 

[J0N]

Mmmmm, still not convinced. I'll have to try it again for a longer period.

 

[Essexcupra]

I'm with you on that. i'm not a 100% sure either. Last thing i want is a blown head gasket/turbo! Really cant afford the repair bill at the mo!

 

[J0N]

It was the wastegate chatter that I did'nt like, this is'nt a good thing for turbo longevity. Something was just screaming at me to remove the by-pass. I know lots of people love this cheap/easy mod but I'm not so sure.

 

[B3LSY]

im thinking of doing this but im unsure to,like u say its there for a reason

 

[ScoobyJawa]

yeah so the ecu can rob you of boost! its a great mod!

 

[Mark300zx]

I found I got more response at lower revs, but lost power at higher revs, weird!

 

[paul-murphys]

i done this before but put back to standard as wouldnt boost as high, it felt like boost was coming in quicker but didnt feel as strong to me,

 

[Havok316]

In the end the excess boost goes the same route, only thing different is surely that it just vents back into the system and not get bottled up in the reservoir? How on earth would this cause damage to engine components? especially if you have an aftermarket DV anyways? I maybe wrong but has anyone ever suffered problems by doing the n249 bypass??

 

[J0N]

The reservoir contains a vacuum to open the DV if the ECU tells it to, in the case of over boosting for example.

 

[blackleonnarsty]

what promlems hav ppl had doin this bypass then? im in 2 mines anwsers ppl????????????

 

[J0N]

Some people like it because it can take away the boost spike but I've always been lead to believe that there's supposed to be one. Also some people report that after the bypass their cars hold boost for longer instead of tailing off but this might only happen if there are problems elsewhere. I know a lot of people love this mod but if everything else on your car is tip-top, ie no boost leaks, your D/V is working as it should be, etc, etc then you wont notice any improvement. I should point out that this is only from my experience with my own car but servicing my D/V (007p) made one hell of a difference and I think this can sometimes be overlooked.

 

[JamJay]

Firstly, nice to hear that you're keeping the car J0N .

Secondly, my experience with the N249 bypass has been good (touch wood) and it's been this way for a year. I found that there was less delay between pressing the throttle and the power going to the wheels with this mod, almost like it eliminated the ECUs thinking of "is it going to spin...eeer...no, ok you can have your boost back". I found that driveability of the car was improved in all areas, when pushing hard, boost was more instant, stronger and held longer. When driving normally and pulling away swiftly from a junction, there was no jerk/loss of power preventing you from making a swift entry/exit from a roundabout for example which with the N249 system in OE form, did quite alot and gave me a couple of @rse clenching moments.