I have been getting moisture under the oil cap on my truck and even a little bit of oil coming out of my rear seal which I assume to be from crankcase pressure. I have an aftermarket forged setup with bigger ring gaps and it just seems to have too much blowby for the factory PCV to be happy. At idle, I have good vacuum going to the PCV, but when I pull the clean side hose and cap it with my finger, I don't ever seem to get any meaningful crankcase vacuum (I don't get any puffing as if I have a bad ring and the truck runs the same as when I installed it). Has anyone ever drilled out the orifice in the PCV system to try to up the PCV flow and restore crankcase vacuum or do most run some sort of vacuum pump or even OCV once they get to this point?

 

You are drive by wire, aren't you? If so, in my opinion having a larger orifice shouldn't hurt anything. Is the PCV vacuum source between the throttle and the blower? So that it sees no boost

 

Yes to both. Drive by wire and PCV vacuum is coming off the blower behind the throttle body in front of the rotors.

 

I don't think that your crankcase would become too much pressurized, because excess blowby should go backwards through the clean side hose. Maybe it takes less pressure than I imagine to cause a crank seal to weep.

 

Definitely seems like there is some clean side flow too.

 

I have breathers on both covers and pull vac via a -10 on my valley cover. In boost it can vent through all 3 if needed as I have the Mighty Mouse catch can with the breather check valve.

 

Aftermarket valve covers? And did you just drill and tap a valley cover for an AN fitting?