kirban's pcv inline check valve

[2QUIK6]

Alot of the quick 10sec cars and faster have some sort of crankcase ventilation. At WOT there is no crankcase gases getting ingested because of boost so no loss of power. As far as 4in vac, thats not enough to ventilate much, notice anytime you mash the pedal, even on slight inclines, the vac goes to near zero, in which case even with no restriction you will get no ventilation. I wouldn't worry too much about it either with or without the check valve, as mentioned, not necessarily needed if the PCV is kept clean and new I just don't check mine that often so its just insurance for me that nothing is going into the cc.