Some may remember i had boost surge when i bought my octavia. after checking a few things i thought i had narrowed it down to the map. I had a standard map put in and it was exactly the same so the afm was changed and the n75 disconnected and manual boost put in. It ran perfect. But with manual boost control it kept going into over boost protection at 12psi so today i have put another new n75 in and its back to surging. It has forge 007. de cat & n249 bypass (makes no difference to the surging).

here is a couple of videos of the boost gauge. If anybody can give me anymore clues i would be very grateful. i love this car when it runs right but cant live with it like this. If it doesnt get sorted this time i will break it.

This is going through the gears.

 

This is from 50mph in 5th gear with foot flat to the floor.

Looks perfectly normal!

 

So the car has now a standard map on only and its still misbehaving?  What fault codes does the ECU have?

No it was mapped with manual boost control in. But it was doing the same with standard map. Without n75 it runs really well for a while then goes into overboost. But with the n75 in its all over the place.

No codes at all. It had maximum boost exceeded and brake light switch but both are sorted.

does anybody think removing n249,sai etc could cure this? the thing i cant get my head around if i remove the n75 there is no surging at all but it goes into limp mode as as it hits 12psi

Honestly, I would get it back to stock and start from there!  Just my 10p anyway.

 

Mines 100% standard bar remap and is fine with all the extras.

I am thinking to flash stock map back in and see if i can sort it from there. But then on the other hand it was doing exactly the same with stock map so would i really gain anything?

So everything else on the engine is stock, no boost controllers etc?

Yeah other than de cat and map its totally standard. Just been and got a map sensor but my missus needs the car for work so i will have to fit it tomorrow.

Have you got VDCS, can you do some logs ??

 

 

I'd agree with back to basics and go from there.