Critique this PCV Setup
 

Got the motor torn down today for heads and cam swap plus supporting mods for the turbo, and figure I might as well do the PCV system while I'm at it. John's (nonnieselman) other thread inspired me as well. I came up with a design that's rather elaborate, but I think it will work great, no downsides really other than complexity.

In this setup, the catch can is filtering the air in and out of boost (I'm trying to use the 2-port unvented AMW can I already have). The air vented from the crankcase in boost goes back into the turbo so it's burned instead of smelling like ass. When out of boost, the air venting the crankcase is filtered w/o needing an extra small filter. No crankcase breather. The factory line on the TB is capped. Downside is needing three checkvalves along with the PCV valve.

Thoughts?
Issues with tuning?
Do we have to worry about the amount of air that is bypassing the MAF by going through the crankcase?
A small amount of oil will probably still get into the turbo in boost, is this an issue? I could run that crossover line to a small breather I guess.


Idle/out of boost:
Attachment 128508

In boost:
Attachment 128509

Makes sense to me, I think it should work well.
One thought or question maybe. What would happen if you put the vent on the pressure side of the turbo and blow it back to the engine, you know the side that smells like ass?
I am wondering how much vapor/oil will foul the turbo if the "ass" vent is going on the sucking side of the turbo.
I only ask because I have seen how much "ass" comes out of my vents on a hurt engine. Your engine or any properly working engine will not barf as much out as mine does, but there is a combination of fumes, oil, and condensation in that "ass" mixture that I would not want to see running back into my engine.
One more note, since the fumes are being vented back to the engine to be burned, where is your MAF or SD sensor and how much will that cause issue with that part of the system?

Why use 3 check valves? Just put one where it exits your catch can before you branch it off to the other 3 locations. Also in your first illustraion your arrow is pointing away from the turbo intake. It is still going to be pulling vac even at an idle. I think the catch can should also be branched between the air inlet @ the turbo or its going to suck up some oil from the passenger side valve cover.

The ass vent pipe needs to go to a zero pressure location, otherwise in boost the air from the crankcase has no where to go. The turbo inlet is a good spot since in boost there will be a little bit of vacuum here and it will help pull blowby air from the crankcase.

As for tuning, I'm not sure. I'm planning on keeping the MAF. Out of boost, some air is bypassing the MAF. In boost, some air air is being double counted by the MAF. I'm guessing this is something that can be "built into" the tune.

The left-most check valve is needed to keep crankcase blowby from getting sucked into the turbo when in boost.

The middle check valve keeps prevents the engine from sucking in fresh air that hasn't been through the engine yet when out of boost boost. If this valve wasn't here then it would basically be bypassing the PCV system.

The right-most check valve prevents boost from leaving the intake manifold when in boost.

The engine will be pulling WAY more vacuum than at the turbo inlet. The vac at the turbo inlet should be relatively small unless the air filter is undersized or clogged. The catch can is in-line between the engine and any air that is going into the turbo inlet, as per the 2nd diagram. But, catch cans aren't perfect and I may just run this crossover line to a vent so I'm not fouling my intake piping with oil.

I still dont understand why in your first dia. the arrow is pointing away from the turbo inlet going towards the passenger valve cover where it says check valve. If your engine is running then there is going to be vac. in front of the turbo. Even at idle.

The vacuum produced by the engine itself is FAR greater than the vacuum before the turbo (when not in boost). The check valve you speak of prevents crankcase blowby from getting sucked into the turbo when in boost. The blowby needs to go through the catch can first, then it goes into the turbo.

The only time there will be a significant amount of vacuum before the turbo, in a 4+ inch pipe no less, is when the pedal is mashed when the engine is moving a ton of air. This vacuum will then help draw the blowby from the engine.

I think your system will work fine. I have seen the others that use the exhaust to draw the "ass" smell out of the crankcase but I have always thought it is not a good solution for anything driven on the street. Can you imagine the smoke coming out your tailpipe when the system is hot and all that garbage is going through the entire exhaust system?? Nasty!

So where are you guys getting check valves? Preferably with the lowest opening pressure possible. Someone said Autozone but they don't have any, or I couldn't them. Lots of PCV valves though!

Most PVC type valves act as check valves, but I'm sure there is something more industrial out there that will last longer and is cleanable when needed. I will look around some.