Logically I'd think the opposite should happen with a binding piston spring shouldn't it? Would keep it from returning to sealed, not the other way around. Also not seeing any reason for the DV to rotate as it is a simple up/down movement. Some require free movement to spin, but I don't see why the DV+ would.I think I may have found a culprit. Much like some other "cheaper" aftermarket wastegates like the one I had on my MS3 the piston needs to rotate. The spring was binding badly inside. I had a Forge BPV replaced twice for the same thing on my Mazda.
I put the stock one back in, see what it does today.
The DV+ is much better at holding pressure, while the stock leaks like crazy at full boost. It also uses a pressurized system to relieve just enough pressure to keep from surging instead of dumping everything. Great increase in throttle response. It's not really a performance mod, I'd consider it more of a reliability/driveablilty mod.
You mean the one from stock DV? While it may help with the spiking, I'm not sure it will keep it from overboosting as that's not the DV's job.
No I just put the stock valve back on and it feels much better. I'm expecting to see much less boost at peak and probably boost tapering off like it did before I put the DV+ on. I'm looking at the HKS SSQV myself, I love the sound of that thing.
I'll try to revert back to stock when I get home, but I don't see it helping much. The wastegate should be keeping the turbo from creating that much pressure not the DV. The DV's job is to relieve pressure upon throttle decrease, not stay open at WOT to level boost.
That was my guess, the DV+ may be the cause of the spike to 30psi when you let off. The 26 psi steady boost may be the WGA or as you said, maybe a leak?