Hi all.

I have a eur. spec 2004 2.0 WRX STI with stock VF35 Turbo(ported),
gruppe-s header and helix up-down-centerpipe and muffler.
The car is ECU-TEKked and runs boost 1.3bar without any problem with the stock tmic and airfilter.

Recently I installed a Perrin Front mount Intercooler together with a Perrin Short Ram intake since the stock intake didn't fit anymore due to the piping.

Now after installation I am having problems wich might be a sort of compressorsurge starting in 4th gear.

When I accelerate and the engine revs up to 3500 rpm a heavy fluttering noise is heard and the turbogaugeneedle is vibrating alot. The boost is not stable.
when slowly accelerating further by easing on the gas the fluttering dissapears at about 4500rpm. After this, full throttle can be applied and full boostpressure is reached without any problem in the higher rpm's.

I tried 3 types of Bov's (Forge bov*, Original bov, and now Apexi bov)to see if it could be cured, but so far without success.

With this setup I went to the ECUTEK tuner for a remap and hopefully to identify and cure this strange issue.

Unfortunately whatever we did didn't cure the flutter.
We had to lower the boost at the 3500-4500 rpm range dramatically (0.9bar)to make it somewhat drivable. in higher rpm's 1.3 is again no problem.
The mixture is ok all the way and there is no knockcorrection, so i think clearly a turbo related issue.

Since I tried 3 bov's this can't be the cause.
Also a leak is out of the question since in higher rpm's the pressure is reached and stable.

Can any tuner identify the problem and help me out with this issue?

I would be very gratefull.

Thanks Barry (The Netherlands, Europe)



*>The forge was by far the worst, this one made fluttering happen when changing gears, so it had too less capacity to remove all the air in fmic system, worked fine with the stock tmic however..

 

check an make sure ur fmic piping an clamps are all on evenly an tight. my turbo needle use to bounce a lot b4 i checked all the piping.