I recently picked up an R56 JCW, details in my signature. The previous owner did the PCV hose delete with plugs on the valve cover and intake, turbo side is unmodified and has no catch can. My oil consumption doesn't seem to be any worse than normal. It's better than my '09 MCS that is bone stock. I've read through about 10 years worth of discussion debating this modification and there still doesn't seem to be any consensus on what's best for the N14. As of 2020, it seems that the thought has evolved to a dual catch can setup being optimal.

For those folks that have plugged the intake side PCV... How long have you ran it that way and what are your long term results both positives / negatives? With 153k on my JCW, I'm deciding whether to change over to dual OCCs or maybe leave the PCV delete and add an OCC to the turbo side. Also, does being stock vs modded matter?

 

I have been running it for 20000 miles now, and have had an oil catch can on the other side. The crappy winter blend gas is the only time when I see more stuff collected in the can. I blocked it to help keep stuff off my intake valves, there was some oil residue in the tube when I took it off. I also had some oil both side of my stock intercooler, last time I checked my G+ it was clean on both sides, this was installed after OCC.

if I were in your shoes I would install a catch can on the other side and be done with it, would just leave the other side alone. Pull your intake tube off the turbo and you will most likely are going to see some oil.

 

Intake tube and turbo are actually clean. I'll check the intercooler next.

 

So I'm considering at this knockoff Mishimoto OCC with the bronze filter. However, looking at the illustrations, shouldn't the filter be on the outlet side, not the in?

 

That is pretty close to what I’m running. I don’t have anything in the filter housing, I could fill it with copper mesh, but no need for it really, it catches what it needs to catch and one more thing I would have to clean when emptying it out.

 

I've tried extensively to eliminate the oily air from entering the intake manifold. I've done the PCV plugs with OCC, just OCC and left the factory setup in place. After 10 builds, I now leave it as stock. The OCC did zero to remove the oily air and only created another maintenance task to monitor with no value. In fact, I went back to early builds and removed the OCC and plugs. You would need a revised valve cover & PCV valving to best remove the oily air. The motor wants and needs to breath. I would design yourself a walnut blasting tool and use it every ~40K miles (before the carbon builds up too much).
I've had freshly rebuilt motors show the presence of oil in the intake after a few thousand miles. It is what it is. My rebuilds that run the best are the ones that the owners drive them hard. Drive it, enjoy it, then deal with the carbon build up around 40K miles and save yourself the concern of always checking an OCC.