Positive Crankcase Ventilation (PCV) system improvement

The PCV is entirely packaged in the cam cover. It's supposed to extract oil vapors from the crank atmosphere before recycling this air in the engine.
However it does not contain either filters or efficient baffling (turbulences are an efficient way to separate oil and air).
Additionally the output passage that goes to intake in front of the throttle is narrow and contains a restriction. I found this passage can be enlarged up to 13mm diameter which is not so bad.
There are also restrictions on the other side of the hose connecting cam cover to the intake ahead throttle.

The PCV system can be opened and modified.

The hose connecting MAF to throttle body. PCV connection is restricted (poorly finished).
The 90 degrees plastic tube inserted here is also very restrictive and must be replaced with something larger.