Crankcase Hoses, Catch Cans, and Venting on the N51 & N52

Here is all the info I got on the catch can system, CCV, compiled into one place

• Do not downsize from 3/4“ ID. Will be a restriction
• Magnesium Valve Covers will benefit from a Mishimoto or URP 3/4 One Way Check Valve. Recently found cheaper option at ECCarbuators
• If you are running a magnesium cover, you will have to run a N54 catch can system, or the stock 2006 CCV setup
• When venting to atmosphere, on a magnesium setup specifically, its recommended to run a one way check valve, as without it, you will start burning oil.
• If you are running a plastic valve cover, you can run direct from back of valve cover directly into the PCV heater, you also can run catch can as well but is not required.
• Plastic valve cover has a one way valve and oil separator built into the top of cover
• If you want to run catch can system in negative / freezing weather, its a benefit to mount the catch can on the exhaust side of the vehicle
• PCV heater is a recall item, get it checked out, keep an eye on the connector and contaminates on the heater itself. You can simply not plug it in, it will not give you any check engine lights. Recall item due it always having 12V power and contaminations on the PCV heater which can cause it to catch fire. 
• If you are switching from a 2 port intake manifold into a 1 port intake manifold, having 3/4 Fuel/PCV hose will make it easier, but using a 3/4 vacuum cap, you can delete one of the port hoses, making it a one port hose setup.
  
• The usual catch can to use for the N52, is the N54 one, higher end and other styles of catch can might need a custom mounting setup solution. Make sure the catch can you source has 3/4 (19mm) inlet and outlet. The N54 catch can, does include a bracket to mount to the strut bar for E9X
• Having a little bit of hardline left on the connectors does make it easier to slip on and off catch can hose for maintenance and removal.

Thank ya

Chris