Hello,

Today I fitted a Milltek exhaust on my vrs, it a de-cat non resonated version and strange thing started to happen.

With stock exhaust boost was around 0.9-1.0 bar max and was holding boost OK to the red line, never drop below 0.6bar.

Now, boost spike is around 1.5 bar! and drops to 0.7 and then back to 1.0 bar. I can hear, see (boost gauge) and feel clearly this boost fluctuations.

Example; Driving along the highway in fourth gear and slam the throttle all the way, boost jumps to 1.4bar, then to 0.7, then 1.1 bar .

I have N75J valve, so I have replaced it with stock valve but the problem is still there, also I have turn another 4 clicks on forge splitter valve but nothing.

Vag logs don`t show no DTC`s except 16804 " efficiency below threshold" which is caused by de cat downpipe, also reset of ECU didn`t help.

I have checked all the hoses but everything looks OK.

Car is remapped so is it possible that is something wrong with the map?

Best regards

the reason you are getting spikes is you have just put a free flowing exhaust on so the car will spike harder you have to get the map ajusted now to take into account the new mod. this will always happen when you change parts like this.....

only way to sort it is map tweak

p.s use the standard n75 valve the others just give you spikes and there crap and get this sorted asap as it will not do the turbo any good spiking that hard .

hth

who mapped your car mate,ive a decat exhaust on mine and never noticed any boost problems.

Good advice from westallc.

TNX all!

I called the guy who chipped my car and he said he will upload my stock map, just to eliminate the problem with the map.

Btw; With Milltek fitted I can spin my wheels up to 3rd gear! it is insane how car is performing now.

Definitive the best mod I`ve done so far....

Best regards

OK, here is a update;

They have uploaded stage 2 map and now there is no fluctuation till 5000-5500rpm, after that it fluctuates sometimes from 1.3 - 0.7 bar.

Also the peek boost has increased to 1.7bar (24,6 psi), it holds 1.5 bar to 3.500-4000 rpm, after that it starts dropping to 1.0bar.

Is 1.7 bar too high boost? Will I blow my turbo really soon?

Best regards

if thats on a k03s then your turbo is going to last all of 5 mins

It is raining almost 3 weeks without stopping here and I can`t log this because my wheels are spinning like crazy... :S

But today I went to a mechanic shop and they have measure AFR with external lambda sonda and some other equipment and said that AFR is OK, only problem is when boost starts to fluctuate AFR goes crazy.

As soon as weather allows I will log boost, N75 and other stuff and post back.

TNX!