Honestly I can't confirm overboosting or boost creep with a Turbo back exhaust, but I can say that I have been running a full catless uppipe+downpipe+exhaust for quite some time and I haven't been noticing any problems.

I do not have any gauges so I cannot be that accurate.

 

Will be fine!

 

Yes you will be fine, I ran a turboback, uppipe, and i/c hoses and everything was great. You can see before and after in a thread I made right before this one. I noticed a bit of boost spiking occasionally with the stock ECU, didn't happen too often and wasn't spiking very high, and I also had tightened the wastegate actuator arm a bit, so that didn't help

https://www.i-club.com/forums/engine-power-ej20t-pre-2006-wrx-jdm-60/road-dyno-cobb-stage-2-without-accessport-68306/

 

The stock wastegate arm is adjustable. it's under the stock turbo heatshield, pretty simple to do. You tighten it up a bit and it puts more tension on the wastegate spring and helps keeps it shut longer, hoepfully leading to higher boost, which was the result with my cobb stage 2, I wasn't anywhere near their target boost levels and tightening the wastegate arm up added an extra psi on without boost spiking(which showed up when I went to stock mapping) I don't know exactly how it all works but thats the basic idea, tightening too much can easily lead to boost spikes.

 

I have read many STi owners have had creep on their vf39s when going catless. I do not believe this is an issue with the TD04s. It is seems to be a often occuring problem for VF series turbos in particular (34 and 35 the ones i've seen complained about most often).

With a stock turbo you should be fine. If you upgrade your turbo to a larger VF turbo, just make sure you have the wastegate ported before you install it... I wish I had :-/


jason