This is a great picture, Thanks Sekred for the image!
There are two Vent lines to discuss here.
#1 is on the left in the picture. It goes from the PCV Valve near the back of the engine, along the vent hose, and into the Intake Manifold.
This vent hose is where we have all been installing our OCC's, for good reason. During low boost or no boost (idle) conditions, the majority of the Crank vented Oil goes along this path. Putting an OCC here helps to pull that airborn oil out of the system, preventing it from hitting the back of our intake values (hence - hopefully - preventing carbon build-up on our intake valves)
#2 is on the right in this picture. It goes from the Valve Cover to the Air Intake (just upstream of the turbo).
This vent hose is where oil goes when we are under boost @ the intake manifold.
I'm NOT SAYING the valve cover is under pressure.....
Under boost,
we have a HUGE Vacuum on the Air Intake side, and oil vapor is pulled from the valve cover into the air stream headed towards the turbo (and more importantly - our inter-cooler).
I can understand the need (and desire) for an OCC on line #1. It keeps excess oil from entering the intake, and carbonizing our intake valves.
There is clear evidence from users that these OCC's do capture airborn oil.
For line #2, having an "oily" airstream (let's ignore that its HOT air coming from the Valve Covers) headed to the turbo - and then into the Intercooler - seems like another bad situation.
Especially if we want to keep oil out of our air stream (both under vacuum and under boost)
Question: Wouldn't adding a second OCC to line #2 protect the inter-cooler from getting gunked up with oil residue? .... and out of our intake Valves?
I believe this line is not under pressure (when we are under boost), so the OCC would act similar to the OCC in line #1 (?)
The
CFM Baffled Valve Cover vent might / should allow you to remove line #2, and just Vent the air to atmosphere. However, if you don't want to VTA, I think installing a second OCC in line #2 would be important.
I already plan to install an OCC on line #1. Worth it to do so in line #2?
-- Max