Many have problems with this and many solutions are suggested to resolve this.
Ever since my K04 build i have had this problem and many solutions have been tried incl. fitting the RS4 pressure valve. not that it made any harm but my problem showed below wasn't resolved
At a little Meet a couple of month ago i started to talk with a halfswede, danish guy living in sweden, and he had had the same problem with his ed30 after fitting exhaust and getting his map just right.
He has helped me log to see and understand the problem.
Apparently some software developers are very cousios and when they map the write so that the system runs very fat. For example the std. ED30 map runs with a lambda value of
0,83 (the higher the number the leaner the system runs) these software writers ask the system to request a value of
0,75 which is
very fat .
What has happend with my car is that after app. 2800 rpm the system request the
0,75 and the system accepts a difference of this value of + - 25%. when reaching above 5000rpm at wot the 25% is exceeded and the system lowers the boost until it is able to work within tolerances. then the boost goes back up again, with a very annoying hold in accereration as a result
well after a very hard battle to get my softwaresupplier to first of admit and supsequently changing the map for me, i now have this instead
Now thats more like it
Please let the experiences flow to the screen in here