In boosted applications, the intake manifold will be under vacuum only at very low rpms. Most of the time, the intake manifold will actually be under boost and therefore will be under positive pressure. Therein lies the problem. Even though the PCV will open under positive crankcase pressure, that positive pressure created in the crankcase by blowby is acting against a greater or equal positive pressure in the intake manifold. When both sides of the PCV valve are at the same pressure (pressure is acting on opposite sides of the diaphragm), there will be zero flow because the valve can’t open. That means that you’ve now positively pressurized the crankcase by blowby now making the PCV system operate in reverse so to speak. So Ash is the system you designed still gonna function correctly in a boosted application? If you wanted to eliminate the so called smoking problem (which I dont particularly have on my supercharged Dakota or my TT Z) why not go about eliminating the PCV system with a dual vent type system?? It seems to me that the smoking you were experiencing could have been that your ring land was missing a 2 foot section out of it....with the dual vent system you also will eliminate the dilution of air/fuel octane by the oil vapors introduced into the system. Draw back of this setup is having to clean the lil breather filters you install on a pretty regular basis, works great on the Blown Dakota though.
'Philosophy of Money..........
It neither makes you happy nor unhappy when you save the first dollar you ever made, it only makes you happy when you finally spend it!'
09:27:20 09/30/02
