Gotcha. And under boost the gasses couldn't escape from the crank through the PCV because the manifold is pressurized. I think I'm getting the hang of this lol. My idea for a frankenstein setup with zero gunk getting into the intake is this:
Front valve cover has a breather filter, but with a check valve behind it so air can only go in, not out. Rear valve cover has one line with a check valve so air can only go out of the crank case, not in. This line goes to a breather tank, which collects material like a catch can, but has a filter venting to atmosphere. No return line to the intake tract or intake manifold or anything. Any time the crankcase experiences negative pressure, filtered air comes in the front valve cover. Any time the crankcase experiences positive pressure vapors escape through the rear cover. The check valves ensure this is the only way air can move. Now you have ZERO gunk getting back into the motor and also free up a port on the intake manifold to use for meth or what have you.
Any reason that setup wouldn't work?