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the correct way to do the n249 and SAI bypass

conorc

Active Member
Dec 26, 2012
66
0
belfast
cool thanks for that mate, some pics of the SIA would be great... Alot of these things seem more complicated until I start the job and then its fine! Still trying to learn my way around the cupra engine, have only had the car a few weeks! thanks again :)
 

vaux_gled

Guest
does the n249 bypass make the car run any better or is it just to get rid of some crap on top of the engine.
 

conorc

Active Member
Dec 26, 2012
66
0
belfast
Thanks mate, ill get them ordered. How many of them would I need do you know? Sorry for all the questions!
 

gammon11

Active Member
Jul 12, 2010
86
0
Bypass done with two resistors of ebay and sai has also bin removed and the plug put out the way. Cjeers
 

nathan_20vt

Active Member
Mar 30, 2013
365
0
Kings Lynn, Norfolk
I know this is an old thread but I'm looking to bypassing my n249. It's my first turbo car so still getting used to it. This looks a bit confusing, is it really that easy to do? Don't want to mess anything up
 

Vladimir

Guest
I'm most likely being a plonker here but where do you run the pipe from the turbo actuator?
Just done mine and and routed it all up on the same line. Ie with DV, boost gauge and turbo actuator. Is this right?
 

mc funbot

its a beast its got boost
Jan 29, 2010
1,473
4
sunny kettering
www.seatcupra.net
Right if you have removed your sai you just blank it if. If you have not then guy run it from the actuator to the little silver bit in the side of your block. Just 1 like from that to the actuator that's it pal.
 
Last edited:

majesty78

Active Member
Oct 6, 2008
490
2
Austria
Still not a good idea to remove the N249 and let the DV work only from intake vacuum.

The ECU and it's programming is not designed for this modification, it is designed to work with the N249 and the vacuum reservoir.

With a fast enough logging tool (NOT VCDS, thats creepy slow) or an external wideband lambda sensor you will quickly see the malfunction and downsides of removing the N249.

Especially on part throttle / let of throttle conditions the N249 has an essential function to keep upright the correct lambda.
This function is deleted with removing the N249 which leads to enriching lambda spikes.

IMHO this is not a "tuning" but a de-tuning mod....getting the engine lambda control system in a mess....
 
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