Originally Posted by charosenz
I am fortunate that this engine did not create any appreciable pressure at 5 lbs of boost with the 1/4" vent lines. If it did, it was less than what I could see on the MAP gauge I was using, probably 1 lb or less.
Case pressure is typically measured in units much smaller than PSI. For example, the Lycoming case pressure limit is something like 4~5 inches of water. One (1) psi is 27.67 inches H2O. Perhaps a re-test with a manometer? I'd expect a healthy Honda to exhibit less blowby than a Lycoming, so an accurate baseline captured now may be useful as a diagnostic tool later.