[SOLVED] Possible boost creep issue (20psi at 5k rpm)

What's up fellow Mazdaspeed monks - I've got a '12 MS3, owned by me since new, 119k now, the usual bolt ons with the exception of a DP. Stratified tuned by Nolan about four years ago. I've left the car alone since that tune with the exception of adding a Turbosmart Kompact BPV to replace the stocker. Also replaced a dying high flow Magnaflow secondary cat (9 years old) with a brand new one earlier this year. Car is no longer a DD and it's strictly for enjoyment at this point.

Earlier this fall, I was experiencing an audible boost leak that led to me doing a boost leak test and fixing a number of small leaks that may have been there for years, and I was just unaware of them - I had a leak at the hose from the intercooler to TB (loose clamp - now fixed), a small one at the little hose on the BPV (bad spring clamp - now fixed) and a noticeable one at the BPV to intercooler interface (I didn't have a gasket there, oddly enough - got one and fixed it).

Ever since fixing those leaks, I'm experiencing what seems like boost creep above 5000 rpm. The turbo is obviously a flamethrower at that point and I have a little touch of KR to demonstrate that - I'm holding more than 20psi above 5000, which shouldn't happen, as the tune should be tapering down to 17-18 psi by this point. What I'm wondering is that if the combination of the fixed boost leaks, the new cat, and the aftermarket BPV has pushed the hardware out of the parameters set by the tune, and if I need a retune. I'm going to swap out the Turbosmart for the original BPV and give that a try tomorrow. Car pulls strong as shit up to 5k, it's just that stuff is getting weird beyond that and I don't want to push it. I'm still on an old ass Cobb AP V2a and Stratified won't tune on it (I asked), so will need to have Freek or PD write me a new custom tune potentially.

 

Forum is quiet these days... guess there aren't that many of us left. Anyway, I swapped out the Turbosmart for the stock BPV, and the issue feels about 90% better. Guess the Turbosmart was the culprit. I did notice that the spring on the OEM BPV was much, much firmer than the Turbosmart, so I'm going to see about getting a stiffer spring for it as a next step.

 

I don't understand why they wouldn't tune on an ap v2. Fixing the boost leaks is likely the source of your problem would need a retune to correct

 

They said it was GreenSpeed (EPA crackdown) related. Although they're in Canada. Both Freek and PD will tune on a V2 after I asked.

 

Update to this thread: turns out I had a leaking BPV. I was running a Turbosmart Kompact Plumback. Swapped it out for the OEM and it pulled cleanly all the way to redline, holding boost. I then opened up the Turbosmart and found that it had a green spring (i.e. too light). Swapped it for a pink one and now it holds boost perfectly. Still on the same tune.

 

Blue two shims