Originally Posted by
lkailburn
PCV system is not all that effective without vacuum sources. thats like asking vapors/oils to JUMP up and out of your block.
-Luke
So how do the pressures relieve themselves when boost pressure is present?
You would be surprised at how high the crankcase pressure can get and it doesn't need anything but a place to go to remove itself from the crankcase.
On another note, vacuum pressure draws those nasty gases back into the engine to gunk things up and burn in the combustion chamber.