So I wanted to share this with you all because honestly, I think it is an EXCELLENT way to not only improve performance and longevity in your engine, but it also ELIMINATES the worst BMW invention since the window regulator, the crank case vent valve!
I was working on reducing my oil consumption and it led me to a thread about catch cans here.
A friend of mine had an unused catch can from a turbo motor he never finished and he let me have it so I figured I would try it. I basically copied the OP's design from the thread. The only difference was my can had 3/8 fittings so I had to buy a 3/4 to 5/8 reducer and then a 5/8 to 3/8 reducer for the valve cover connection and a 5/8 to 3/8 reducer on the air distribution block side. I used the Oreilley Auto Parts PCV valve listed on page 2 and installed it between the can and the air distribution block (on the vacuum side). I then just capped the oil dipstick return hole with a 3/8 cap. Then pulled the CVV and we are done.
All I can say is wow! There is no denying the car has more power due to better sealing rings under the increased vacuum. And it is INCREASED vacuum. At idle, you have to really WANT to get the oil fill cap off, when you do there is a large WOOOSH as you break the vacuum seal. But this extra vacuum is what helps the rings seal better as the M54 uses low tension rings and many believe extra vacuum is just what the doctor ordered. Down side is, if you have older or ailing valve cover gaskets, oil filter housing gaskets, or even leaky dipstick tube o-rings, you will want to replace them as they will likely let go under all this vacuum. All my stuff was new so I have had ZERO issues.
Beyond the increase in power I also lessened my oil consumption by 300-400 miles per qt. I KNOW my car has gunked up oil control rings, so a healthier, lower mileage engine will likely benefit more.
The other super cool thing (IMO) is the amount of crap that is no longer being sucked into my intake and cylinders (probably what gummed up my rings to begin with) and being caught in the "catch can". And I have ZERO chance of ever having a CVV related failure or hydrolocking the engine because the valve locks up and sucks all the oil out of my dipstick tube and into the motor.
I only have to empty the can about 2 times monthly. But you will likely only have to do it every oil change. I just get more blow by and crap because of my ring issue.
Before you run out to ebay and buy the $33 cans let me just remind you, ALL CANS ARE NOT CREATED EQUAL. Some of the ebay ones are simply a can with two inlets and NOTHING inside the can. What you want is a can with internal baffling and some sort of media (mine uses stainless steel scrubber pads like you can buy at the grocery store) to allow the oil and liquids to grab onto so only clean air and vapor make it out of the can. This is paramount because the can won't do its job well without that media.
So good luck, I think this is a MUCH better way to do it than what BMW did with the CVV.
Stuff it catches...
With COLD AIR KIT INSTALLED....I have since re-routed the hose under the heat shield.