Good Daily Driver Scenario, Not Really!

[BGGSTin]

- Alright, when I purchased the things for my car recently and put them on, I didn't think I was going to have boost creep issues. I was trying to avoid this via: 38mm external gate with external dump, stainless O2 housing, 3" Full exhast, Equal length headers, Ported Evo III.
- Here's the issue, Using AVCR I have boost controlled at ~1.0bbar, from spool up to >~6k. After 6K however is when the real problems start, as I'm boosting to increadibly high levels of up to 1.8bar so far. Yessiree, that would be on an internally bone stock motor
- The problem seems to build up, 5th gear ~WOT, the AVCR selenoid fluctuates boost, say when it hits 1.0 knocks it down to .8bar. As the RPM's increase however it becomes progressively worse. Say while fluctuating from 5K - 7K it goes like this 1bar to .8bar to 1.1 bar to .8bar to 1.3 bar to .85 bar to 1.5 bar to .9 bar to 1.65 bar to 1 bar to 1.8 bar.
- Just as an FYI also, when it creeps, it feels like Vtec [sounds also]. Once the RPM's get to 6K, almost instantly, shoot to 7.5K . What I "think" is going on here is my bad clutch coming into play, Stock clutch already slips if I try to get any kind of quick start. I'm going to Sloyboys this weekend to get a 3500 and see if that will cure this problem, but still, if my clutch were slipping would that not decrease the load on the engine, thus lowering the boost, or at least not making it shoot up so high?
- For now I just don't bother with high RPM driving but nevertheless, the problem is still there, even with the precautions I took in the beginning. I'm trying to think of where I could possible have a restriction causing it to creep so high >~6K.
- Anything to do with my 'gate being mounted on the O2 housing, rather than the headers?

Sorry for the length, but I try to get everything in for diagnosis; sorry if I left anything out and thanks ahead of time

 

[BGGSTin]

Thanks for the advice.

Yes, Slowboy ported the whole exhaust portion of the turbo to match their O2 housing. After a little discussion with Nate, when I go up there this weekend to get my clutch and new dump tube, were going to throw on a manual boost controller and bypass the AVCR to see if it eliminates the problem. Regardless, I'm selling the AVCR because I don't really like it, I need to stick with my motto, "function over form "

 

[Steve93Talon]

First off, since your wastegate is on the o2, did you port the wastegate passage on the turbine housing? It's not gonna do you much good having a 38mm gate if the stock 24mm hole is still there. It should look something like this:

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Other than that, I'd suspect the AVC-R. I know they can be flaky and hard to set up. Try bypassing it and just running a hose from your boost source straight to the wastegate and see if it holds spring pressure to redline.