[Travis1807]

Not having had a BMW before my current 2013 X5M I’m not to familiar with their CCV system or PCV valves. Historically PCV valves have always had high failure rates or just plain won’t work the way they are designed to in forced induction applications. Our CCV system in particular has remained especially elusive to me. So recently I experienced a boost leak that forced me to replace a few CCV pipes as well as the intake air duct on the engines 1-4 side and decided to do some digging around.

I took the old pieces that I had to replace apart to get a better look at our PCV valves as well as taking a closer look at the CCV connection point on the intake air duct. I had originally planned on replacing the entire set up with SS hose, –AN fittings and aftermarket check valves but after examining our system I’m actually kind of impressed with our PCV valves. It’s the first “flapper” design I have seen as large as it is and in theory looks like it will work quite well. It’s crazy to think that BMW succeeded on the PCV design where most fail and then dropped the ball on something as simple as not using hard plastic lines to plumb the CCV system. I also think the size of the piping used was perfect. Normally the largest piping used is -8AN.

Now after I looked at the intake just past the hole where the CCV system connects it didn’t appear that at 33,000 miles there was that much oil vapor from blow-by getting back into the system. I plan to do away with the connecting pipe and add a catch can on each side with -12AN fittings. I believe the dual catch can system will still serve a purpose and will help with keeping a clean intake system. The new version of our S63 engines the S63tu has a built in catchcan on the CCV system. If the improved version of our engine is coming from the factory with a catchcan I think it makes good sense to install one (or 2) on any S63.

Below I have some diagrams of our system and then the pieces that I took apart. I also have some pictures of a M5 with a dual catchcan setup from ASR that I really like, it’s flawless in my opinion . The M5 is using the same hard plastic pipes as us for a portion of the syslem but doesn’t have the same connection points. There are also some pictures of the custom fabricated connection points to connect our current piping to the –AN fittings that ASR uses.

If anyone wants to see pictures of the new S63tu engine and its "oil mist blow-by catcher thing" (aka catchcan) just let me know. I didn't want to post them here and start confusing people.