the Positive Crankcase Valve is a one way valve, pulling air from the cam cover on idle when the intake plenum pressure is low and closing when intake pressure is high (on boost). the actual valve is in the cam cover itself so ppl usually move it to the plenum and run a hose from the catchcan to it. similar to the one going to the intake pipe after afm. so you have one hose (or 2) from cam covers to can, one to the intake pipe and another thru pcv into plenum. if the pcv is just gonna be sucking can air anyway, does it matter if it sucks ambient air?
i assume no because the hole is small for one and the valve is only open on idle. anyone care to correct me?