It seems the factory PCV orifices/passages are restrictive enough that it doesn't really matter how big the oil cap is in terms of air flow from the crankcase into the combustion chamber. If you've removed those restrictions, then the air flow is increased but the vacuum levels should never exceed what the flapper port permits due to the controlled leak it provides. The only difference would be the amount of time required to build up that vacuum, no?
If you had zero blow by and a blocked/plugged flapper port, you could see UP TO engine vacuum on the crank case. This would probably only happen if you've got an issue with your flapper port and this may cause the crankshaft seal whistling problem.
As we already know, the flapper's inward ventilation capability, or at least the existence of the port where that flapper should be, prevents the full engine vacuum from building up in the crank case.
Pulling the oil cap is effectively the same as deleting the flapper as the air flow choke point changes from the flapper port to the PCV passages. If you've increased those passages with an external product, then air flow from the crank case into the combustion chamber will go up, but that doesn't necessarily mean your crank case vacuum has increased.
If the ventilation choke point was never the flapper valve, but instead it was your previous pcv passages, then your crank case vacuum could indeed be higher now than before. But to me, that would illustrate an issue with your pcv system IF a flapper valve was in use because that shouldn't be the case. If that wasn't true, there would never be a point to having the flapper valve in the first place.
So in my opinion, you've currently got more airflow from the crank case, into the engine, not necessarily more vacuum (because you weren't out flowing the flapper port then and probably aren't now unless your new pcv plumbing is bigger than 10AN). Since you don't have a flapper valve anymore (you mentioned in your first post that your high side is OCC->VTA), if I'm interpreting this correctly, you probably have LESS vacuum on the crank case but MORE airflow going into the engine than you would if you just had the flapper installed with properly flowing PCV passages like a factory engine. So I don't believe the amount of vacuum you are getting in the crank case is damaging, since the flapper valve is deleted. You just have a lot of air being sucked into the engine and you may even get codes about the throttle blade position as the DME is needing to adjust it to an unusually closed position. If your plumbing changes are solving your problems with excess smoke from the crank case, I would explore reasons why you are getting so much more blow by than a healthy engine, such as ring land problems and so on.
My new, and current recommendation to people:
Stock VC - Easiest way:
1) Use a PCV delete fitting and put on an 8AN cap, this effectively blocks the head ports(supposedly).
2) Delete the flapper valve with any of the existing flapper delete options
3) Run the flapper delete port to an OCC then to your intake pipe or to the rear of the car
Aftermarket VC:
1) Block head ports (tap/plug)
2) Run one or both VC ports to OCC then to intake pipe or to rear of car
I would have done this from the beginning, but there just isn't a convenient intake pipe for a single turbo without a mess of hoses running around.
