N14S after Catch Can, Pressure Relief Valve on the head is spewing
 

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ok guys, this is my setup. i know it looks wonky as hell but it works.

i have a 3 port cc. 1 outlet (marked with blue goes to turbo inlet) and 2 inlet (one comes from head outlet and other comes from the suction under the manifold). catch can has some kind of filter element under the outlet and baffling under the other 2 ports. there doesn't seem to be any blockage or pressure leak.

yet, after pushing the car to its limits, relief valve (marked with blue) spews oil to the air filter housing.

this wasn't happening before installation. can anyone help me to fix this?

Hopefully this helps. It's my understanding that under normal driving conditions the PCV routes the gases out the port on the back side of the head to the intake. When the point is reached when the turbo is being used, the the gases come out on the drivers side of the valve cover. It appears that since the outlet at the back of the head is blocked of, the only other location where the gases can come out is the relief valve (when the turbo is not being used). I think if you connected the back side port from the head to the catch can instead of the intake to the catch can, this should solve the issue. I use a single catch can and it's only for the drivers side of the drivers side of the system. I'm thinking about adding a second can that would take care of the back side of the head to intake path. The two cans would keep the two paths separate so the PCV would function as designed.

Since your intake manifold is connected directly to the CC, any time you have boost (positive pressure in the intake manifold) that pressure will also be seen at the CC, causing a "reverse oil flow" in the CC. That'll cause all kinds of grieve with your PCV system.

An alternative to a 2nd CC would be to install a check valve in the manifold hose --- a valve that only allows flow one direction. However, with the back outlet blocked, there will be zero crankcase evacuation activity during normal driving, causing gradual pressure build-up, depending on the condition of your piston rings, valve seals, etc. This can affect turbo oil return, which is gravity only --- any crankcase positive pressure can cause oil to seep thru the turbo seals and into the compression chamber, eventually puddling in the FMIC, fouling the valves, smoke, etc. I strongly recommend using a dual CC system, instead of your existing 3-port CC.