N54 PCV/OCC (Oil Catch Can) set up for M18 VC (valve cover) on my 335IS


New Member
Jan 16, 2023
So once I realized the dilemma of needing oil catch cans after installing the valve cover. Due to there being no cyclonic separator, as well as not being able to reuse the OEM PCV or CCV (Crank case vent hose) as the 2 ports (high/boost and low/vacuum) on the M18 VC are both just -10AN. I then order the dual BMS OCC instead of the radium due to price, which didn't have an option for BOV just for N54 or the other. Researched videos and forums through a week to figure out how to configure the BMS kit to the m18 Valve cover. Received the BMS kit without the BOV adapter which is needed wether or not you use a BOV. I was wondering why everyone had it except for me since they'd only link the BMS kit but never the BOV adapter. So at the time of this writing I'm waiting on a reply once Monday comes, so I may order it if it indeed doesn't come with the dual can BMS kit. Then I can finally install this and get my car back on the road.

Here’s a video mentioned from the other forums I read up on that was helpful when I was learning about all the confusing and different sides of blocking the ports, PCV delete, OCC, the oem flapper, high/ boost side, low/ vacuum side etc. Granted I’ve watched the video like 3-5 times LOL.

So I was confused as to wether or not there was a check valve that came for the vacuum side OCC, because it was not put together and once I put it together I realized I didn’t have the BOV adapter.

So before i realized this I assumed there wasn’t a check valve and there were people speaking about vacuum leaks on the vacuum side on some forums. So I then ordered the radium 10an ORB PCV to 3/8 barb.
Then I realized the hose for the vacuum side is compression tubing. Which I now get the pleasure losing brain cells I mean learning more about sizing and plumbing sizing.

Compression tube has an OD (outer diameter) of 3/8 while other hoses for a barb 3/8 will have a ID (inner diameter) of 3/8. I believe so excuse my
Ignorance lol.

So after committing to use everything I’ve ordered, I went to autozone and got a 3/8 hose and then to Home Depot since they didn’t have an adapter. I’ll just show pictures to do it justice lol.
So the radium 10 AN ORB will go directly into one of the ports in the M18 VC. Connect to a 3/8 hose (I still have to cut it just to like 2 inches, then to a 3/8 barb that I’ve adapted to use the 1/4 Threaded 3/8 compression fitting so I may use the BMS 3/8 compression tube mostly.

Now the boost side was a little bit simpler after watching multiple DIY videos. I used the black adapter piece on the beginning side instead of the end of the CCV hose and took off the plastic hose and will connect the 3/4 hose directly over the flapper. While having the adapter side connect to a short 3/4 hose to the 3/4 barb with 10 AN orb to fit directly into one of the ports in the M18 VC. I’m sure the pictures help make it be simpler
Here’s 2 diagrams out of many from other forum posts

Also I’m not blocking my head ports, I’m on stock turbos on MHD stage 2+. The screenshot below and from reading around and watching videos I decided I’ll skip out on it. And come back to it later if needed when I upgrade the turbo

This was a big headache and I thought maybe I’ll share my experience of it all for some other person that runs into the same dilemma. Or just order the radium kit if you have the money haha. Although I do love BMS. Feel free to educate me on anything I butchered or to leave your thoughts and 2 cents/sense.

I’ll maybe update once I have it all installed.


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