I'm not getting much traction on help elsewhere, so I figured I would ask here. I get compressor stall, only under vacuum, around 10inHg. Seems to happen if I back off the throttle under cruise conditions, but I can also provoke it sometimes by blipping the throttle. Is this intake/MAF resonance, or an issue with getting vacuum to the BPV? In a nutshell, you can see the MAF jitter in the graphs, and you can hear the BPV/turbo flutter.
Things that I've tried so far.
- bypass vacuum tank, still happened
- clean and lube Forge BPV
- swap back to stock BPV
- checked line from solenoid to BPV
sidenote: yes, I know EGT and FP logging is broken. It's on my TODO list. I don't really care at the moment since I only run 93, and I only have a modest tune with no fueling issues.
Things that I can think of. I've not tested the boost solenoid. Could it be contributing? I doubt it since it's always 0% DC when this occurs. The valve holds boost even after the car is off, until I disconnect the tube going to it. One last thing. The MAF pretty much rests against the K&N heat shield. I was concerned about this when I first installed the intake, but didn't see any issues, so I didn't think about it. Just a few weeks ago, this cropped up. I suppose that could be contributing, but MAF resonance shouldn't cause the BPV to flutter, at least I wouldn't think so...