Those do a good job of blocking boost from going through a weak/old PCV valve, but I don't see how it magically creates vacuum in the crank case. You really have to have bigger ports, more ports, or some sort of scavenging effect to have really good ventilation. Do you have any idea how that setup increases ventilation? I skimmed their website, but all I saw was something about the magic voodoo of their "unique Flow Controlled One-Way Valve that uses aerodynamic principles to move the valve in and out of position".
Doesn't make sense how that increases ventilation when our OEM setup doesn't even have a valve on the ventilation line. I see how it keeps boost out if your stock pcv is dead and I can see how it helps ventilate more under vacuum and idle, but I'm concerned about ventilation under boost.
