Quote from: Wardog692 on February 02, 2017, 07:32:47 PM
Pardon my stupidity, but what's the difference in a catch can vs a clean side separator? Isn't a CSS just an add on to a catch can? Also, any suggestions on brand (UPR, RX, JLT)?
No worries! The clean side separator does not actually connect to the catch can. The clean side is primarily a fresh air intake. Occasionally, flow temporarily reverses direction, which is where (I suspect) a bulk of the oil is pulled into the intake on the OE setup. All the CSS is supposed to do is prevent oil from exiting the valve cover during these temporary flow reversals. Usually with a CSS install, the OE cleanside ports are plugged and the new CSS tube is run to either the clean side of the airbox or vented to atmosphere with a press-on filter.
An OCC, on the other hand, connects to the dirty side (rear bank on transverse), and vacuum is provided from the IM (during cruise) or the intake piping (under boost) to draw "dirty" air into the catch can, where oil/water/fuel from PCV vapor (hopefully) stays in the can and "clean" air returns to the vacuum source.
Some OCC setups (like JLT) do not pull from both vacuum sources, but can be modified somewhat easily to do so. You'd want vacuum from both intake pipes and IM for maximum efficiency, since you'd be drawing dirty air under all running conditions.
Hope this helps a little. Keep asking questions if something still isn't clear.

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