Hey guys. I hate to ask this question, but Ive been searching for two days and cant find a defanate answer. I have an 07 wagon and I was given a Invidia catless DP, and was going to buy the Invidia N1 race cat back. My question is, will I have to port my wastgate as well as adding a EM to my car to stop boost spike and the CEL's, or will EM be enough? Again Im sorry for making you guys answer this question again...
im going with a catted DP just for that tiny bit of back pressure but my tuner assured me that it wont be a problem with a custom tune using uniChip but then again im just getting a very safe stage 2 93 octane tune
The problem is that the 2.5l flows too much air for the tiny TD04 turbo. Therefore, when the wastegate is open all the way to bypass air around the compressor wheel it is not a large enough opening to cope with the greater airflow that an aftermarket downpipe will create. This leads to too much air flowing around the compressor wheel and overboosting.
Pick up the June issue of SubieSport and read the boost section where they refer to wastegate actuators and the basics of boost. Also check out Unabombers Manifesto on NASIOC, I believe there are several diagrams in the thread to help explain. Try to do as much research as possible.