Here's my test. So I just measured directly at the hose that goes into the distribution box that's connected to the manifold.
So manifold is pulling 16-17 inHG instead of 0.48 inHG?
Does the original CCV system then blocks the vacuum at the diaphragm and doesn't let it pull so much from valve cover?
I guess to confirm all we need to do is have someone with the stock CCV system measure the vacuum?
Which is probably going to be like bmw says 0.48inHG?
So on this case it's true, the vacuum with this mod is 30 times stronger.
Now how much vacuum is safe for the seals?
Just for fun I sucked on that gauge as hard as I could, and it showed 23 inHG lol! So it relative terms that I can relate to, it's not that much suction...
But it's probably enough to stop the oil consumption...
Here's CN90's picture, numbers are just examples.
BTW I wonder if CN90 is still around with thus mod?
Fifty150hs I think your mode is a bit different because you installed a catch can??