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This N249 bypass mod, FAO all of those who seem to dont understand it..


Dec 29, 2005
Sorry to revive an old thread. I've done this version of the mod to the BAM 225 LCR engine before I realised there was a separate guide. Have I knackered it or is it effectively doing the same job? Just been out in it and seems fine. Cheers.
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Active Member
May 15, 2014
Is this the same as the lcr?

I've bought the gear the op linked to and planning on doing it tomorrow!


Active Member
Feb 12, 2012
Ok previous owner has done the 112 bypass but dint but a resistor in so my eng management lights on, not sure ob the mod no nothing about it where how do i put the resistor in and which rwsistor isit thanks


Sep 23, 2014
Hello guys,

I did this today to bypass the n249 valve and also remove the empty air box.
I have revo stage 2 so the valves should be on...
i am attaching an image


Active Member
Oct 4, 2014
I did mine a week ago and have since lost 0.2 bar of boost should i have bypassed the n249 and then got a stage 1 done ? [/IMG]

Sent from my SM-G900F using Tapatalk


Intagram / johnyoung84
May 5, 2015
This is why I won't do it ether, cars are built in this way so taking parts of that are meant to be there is gonna ether cause harm to your car or do nothing to you car, it will just give you more space

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Active Member
Sep 21, 2016
Bypass Thingy!

Probably a stupid question but what are the benefits of the n247 bypass Mod! I'm new to this so please be kind to me. Lol.


Active Member
Aug 14, 2016
This pretty much covers it, just done mine and it is smoother and holds boost longer....

the n249 bypass is a simple mod which just eliminates the ecu dumping boost at low throttle and sometimes it becomes faulty and starts dumping boost randomly and can cause jerky pull off. also it helps hold boost for longer. the n112 and sai bypass/ removal are a bit more complex and all require resistors ect.. to bypass. if after doing the n249 bypass you still experience boost issues then maybe a n75/n112 and sai delete is the answer but in my opinion keep it simple and just do the n249 unless you believe or know the rest to be at fault.
also weather or not your car is standard or modified the n249 bypass works but its best used on a uprated dump valve as the n249 is a protective measure against the stock dv failing.


Active Member
Jun 17, 2011
When you lift off the throttle to change gear, the N249 opens the diverter valve slightly earlier than it would open on it's own. We're talking 0.1secs here, nothing that you can notice unless you have the car on VCDS or similar, but it protects the turbo from pressure spikes and the stress of trying to force air past a closed throttle plate.

That's it, it doesn't open at any time, and it certainly doesn't stop you holding boost etc etc etc.
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