The RB N54 External PCV Kit is the original Low Side system originally developed in 2015, thus it has many years of usage and acceptance from dedicated N54 enthusiasts. This product we have found does wonders in eliminating vulnerabilities in the OEM PCV system, beyond that of what only a simple Internal PCV Valve replacement can accomplish.
With high performance always comes finding a systems weak links, and when you combine that with component degradation over the years you often end up with problems. Problems such as oil consumption, smoking out the exhaust, etc.; we have heard it all from all types of customers with a variety of mileage and turbo combinations. We have found this solution in some cases cures these problems, or mitigates them, many of times. What this means is that your OEM PCV system is not up to the task of the performance you are subjecting it to, or the components on your vehicle are less than healthy (ie. Clogged valve cover ports, Hardened/Cracked valve cover gaskets/etc). When using this kit to the full potential you would ideally plug the head ports, which positively rules out vulnerabilities in the valve cover gasket and valve cover itself meaning it is no longer a "worry"; but plugging the head ports is NOT required - but once again we suggest considering it as soon as possible to get the full benefits.
Another big perk of running an external PCV system is that you can finally eliminate the constant "building up" on your intake valves by inserting an Oil Catch Can into the low load system which is now finally possible. Most of the contamination found on intake valves is in fact due to low load oil collections in everyday usage through the Internal PCV valve and into head ports, which builds up as gunk on your intake valves over time. This is best done by adding in your own Oil Catch Can (not included) and you’ll see first hand this accumulation building in your can rather than on your valves, which you will need to drain at a mileage interval.
The RB External PCV kit we consider most applicable towards the dedicated, high performance, and maintenance savvy N54 consumer; and for those looking for the easiest and quickest PCV valve replacements we still highly recommend our original RB PCV Valve (Internal plug and play setup) for your maintenance or high performance needs.
The kit comes optioned as an "A", "B", or "C" (either "PNP" or "Non-PNP") in effort to minimize excess parts and costs for the consumer as they may have their own methods of handling the install; but our Option A "PNP" is the most comprehensive kit that is recommended. Please note that the PNP kits come with a dual port throttle body adapter, which can also multi-task as your BOV/Diverter reference as well. Also note that the Non-PNP kits are identical to the PNP kits aside that they do NOT come with the custom dual port throttle body adapter but rather just an NPT Bung adapter fitting and thus you must improvise your own 1/8" NPT vacuum reference interface. This is usually accomplished by drilling and tapping your intake manifold and threading in the supplied custom Non-PNP kit bung, assuming you do not already have your own vacuum reference adapter sourced elsewhere.
This is not compatible with our standard RB PCV Valve and Cap as that is an internal arrangement thus they must be removed in order to run the RB External PCV hardware.
We recommend the usage of Mishimoto Oil Catch Can offerings (or equivalent) to work with the RB External PCV kits: Older Model: MMBCC-MSTWO-BK (These have 3/8" NPT Threads for the OCC interface). Newer Model: MMBCC-CBTWO (These have M16x1.5 Threads/with O-Ring for the OCC interface).
The RB OCC Support bracket for the BMS AND Mishimoto OCC is NOW available, which affixes it to the 135/335 strut bar shape. It was design around the 335 model but it does work also with the M3 Strut bar. It does NOT work with the 5 series strut bar.
We strongly encourage reading the below for extensive information, recommendations, and discussions on this product (see post #1): http://www.n54tech.com/forums/showthread.php?t=35535
----------Option B "PNP"
----------Option C "PNP"