In my attempt to better understand the factory PCV system here are a few diagrams from the Japanese FSM for the SR20DET showing the pipes connected to the intake related to the PCV system.
Factory SR20DET Intake Diagram
PCV and I'm not really sure where that lower pipe goes? Lower intake manifold? EDIT: Looks like it goes to the AAC valve
Split air pipe to intake manifold and lower pipe to lower intake manifold? EDIT: Looks like it goes to the AAC valve
I just thought this looked funny.
Another view
Picture
Ever since converting to Speed Density I have a catch can vented to atmosphere and have had a fucked up rich idle issue which led me to this thread. I am going to re-plumb the hose from the Tee on the valve cover to the catch can and back to the intake before the turbo. I will edit this post with results.
In my opinion -AN isn't really necessary for anything in the system. Simple barbs/hose/hose clamps are adequate. -AN only needed for pressurized fluid. EDIT: Ha!
I find it hard to believe that a working PCV system vs Venting to atmosphere would actually net HP gains, but I think it actually will/does. Something so simple but necessary for applying vacuum to the crankcase.
5-13-20 EDIT:
I hooked up my catch can to a nipple on the intake pre-turbo and it didn't really seem to do anything noticeable. However, while trying to determine my idle issue I removed the intake manifold and noticed a pool of oil in my intake manifold. This was probably because I didn't have the vacuum source hooked up causing pressure to build up and push oil out the PCV into the IM. I have not yet checked the PCV valve. Idle problem may be related to IACV, but it looked and tested fine.
