Since you are one of the smartest people on this forum I think you have potential to fully understand some things. That is why I spend my time to write extra. I wrote this elsewhere but I figure you don't read all the links.
Lets start with this
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I've seen data logs of crankcase pressure on my old shop?s wetsump 1100whp 4G63 with only atmosphere crankcase ventilation. 2-3psi. Wooptie fuckin do.
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yes, most vented setups for performance engiens see 2 and 3psi of crankcase pressure. It's easy to say 'big deal' and move on.
Yet. With over ten years of chemistry & physics courses with 20 years of wrenching I have learned a couple things about oil molecules and engine seals.
All engine seals leak. If you install a brand new seal, then let oil sit on it, eventually the seal will age, and oil will begin to leak.
So there is a time limit from the moment you install a seal.
Oil molecules are very small, especially uniform synthetic variety. They gradually worm their way into/under/around oil seals over time.
The only thing that can speed them up, is heat and pressure. Higher temperature causes oil molecules to become more lively, think melted butter vs solid butter. Oil and butter are almost identical. The warmer the butter, the warmer the oil, the more easy it can fit through an engine seal or other tight spaces. In general.
Also, oil tends to pack into spaces, like butter can. When the engine cools off, imagine you cool liquid butter to a more solid or viscous state. it will pack rather well into a corner.
Then, when the engine heats back up, those tightly packed oil molecules start to expand and REPEL each other. So they start forcing their partners away; DEEPER into the oil seal crevice. Each time they pack and unpack they are forced deeper and deeper into the seal.
The other force which assists them is PRESSURE. For a simple example, put a tiny hole in the bottom of a water bottle and watch it drip out. Then, apply some pressure to the top (1psi from your mouth) and watch the water speed up from a drip to a stream.
That 1-2-3psi of crankcase pressure is applied to those oil molecules inside the seal crevice, and it speeds up their progress. If you hook an air compressor set to 2psi to the crankcase and walk away- the oil seals will leak MUCH sooner than if left at atmospheric pressure.
The only thing that can slow down the progress of those hot oil molecules which invade the seals, is PCV. That is the main purpose of PCV, to help pull oil molecules out of crevices, to help remove them from attacking and entering the oil seals and oil passageways around the engine. PCV is what keeps them from leaving the crankcase.
But PCV is not a flow rate. PCV is a PRESSURE setting.
That is why so many systems fail or seem to be insufficient. People modify their engines with high performance air filters and fail to adjust the system to regain lost pcv action. It wrecks the pcv functional pressure of the crankcase.
PCV is a setting just like boost pressure- it must be logged, calculated, and set manually anytime you adjust anything in the intake air pathway. If you alter the air filter to the engine- you must adjust the pcv system orifice and flow to regain the lost pressure of the high flowing filter. There must be some form of pressure drop or pressure will not be controlled and oil will escape and invade anywhere it can.
If you are putting it together now you may start to realize those engines which seem to aspirate oil to their intake manifolds, and fill oil to the intercoolers, all had high performance air filters or no air filters, and original or disturbed pcv hardware.... Yes there is a connection