The background:
The direct injection used on the N54 has a number of attributes, but carbon deposits on the intake valves and a questionable PCV system are annoying exceptions, requiring walnut blasting every 40-50k miles to keep smoothness and efficiency in check. While the procedure doesn't appear to be too bad, it's a hassle and I'd prefer not to disassemble anything unnecessarily on my 7.2k mile 1M.
A few years ago, Rob Beck from RB Turbos, designed some parts to help externalize the PCV system (
https://www.rbturbo.com/products/acc...ternal-pcv-kit). Basically, these parts allow the valve cover to be vented to a baffled and filtered Mishimoto oil catch can (
https://www.mishimoto.com/compact-ba...an-2-port.html), trapping most of the oil that usually finds its way into the intake (believed to be a significant contributor to the intake valve deposits). I liked the design, but since it required the customer design and fabricate a mounting bracket, the project was put on the backburner.
Enter the new Burger Motorsports BOV adapter (
http://www.burgertuning.com/N54_BMS_...m_Adapter.html). BMS recently released this little gem which, like a similar part available within one of the RB kits (they offer three options), is installed between the throttle body and evap valve to provide the vacuum source for the external PCV. However, rather than being equipped with a fixed single barb, the BMS version has two 1/8" NPT ports. This is huge, as it accommodates the new PCV plumbing and provides a convenient way to increase BOV hose diameter from small (able to fit the diverter valve vacuum supply barb on the intake manifold) to 1/4" (recommended by Tial). The benefit of this hose upgrade is a more responsive BOV.
Seeing an opportunity to knock out two projects at once, I ordered both the RB external PCV and BMS BOV adapter. The process of installing the RB system is well documented (
https://www.n54tech.com/forums/showthread.php?t=35535,
https://www.e90post.com/forums/showthread.php?t=1293291,
https://www.1addicts.com/forums/show....php?t=1216651), so I won't go into a long-winded DIY here. Also, keep in mind my install location was made possible due to the extra space provided by my aFe intake (
https://afepower.com/afe-power-54-11...-intake-system). The stock airbox takes up more room.
The parts:
BMS BOV adapter (BMS)
External PCV valve and N54 valve cover adapter (RB Turbo)
Oil catch can (Mishimoto)
3/8" NPT to 3/8" straight barb for catch can (RB Turbo)
3/8" NPT to 3/8" 45 deg barb for catch can (Vibrant Performance)
1/8" NPT to 3/8" straight barb for PCV vacuum supply (RB Turbo)
1/8" NPT to 1/4" 90 deg barb for BOV (Vibrant Performance)
3/8" Gates Barricade fuel hose, looks OE right down to the green lettering
6 mm silicone BOV vacuum line (Verocious Motorsports)
4 mm silicone intake manifold barb cap (Verocious Motorsports)
4 constant tension clamps for 3/8" hose (RB Turbo)
1 constant tension clamp for 6 mm vacuum line
1 constant tension clamp for intake manifold barb
1" wide 1/16" steel strip for bracket fabrication
Bosch EV1 short male and female connectors
Bosch EV1 short 90 degree boot
20 gauge wire, mesh wire loom, adhesive-lined shrink tubing
The process:
Most of the core parts are shown here, including the RB external PCV valve (left), the BMS BOV adapter (center), and Mishimoto catch can (back right).
The PCV valve install was straightforward, just make
absolutely sure not to cross thread the plastic valve cover with the aluminum threads of the PCV adapter. The Gates Barricade fuel injection hose looks OEM and was routed along the existing PCV flapper tubing. The allowed the engine cover to be properly installed without modification.
I initially installed the BMS BOV adapter with the straight barb shown in the first pic on top and the RB straight barb on the bottom. Not liking how the hose routing looked, I moved the RB fitting to the top and used a 90 elbow on the bottom to supply vacuum to the Tial BOV. The ID of my Tial BOV barb was 0.170" so I bored the Vibrant elbow to match.
As previously mentioned, the BMS BOV adapter is installed between the throttle body and evap valve. In my case, this caused two problems. First, I felt like this put too much tension on the wires leading to the evap valve, especially at the end of the connector. Second, the wires at the end of the connector touched the firewall insulation. Probably not a big deal for most people, but it bugged me. To remedy, I fabricated an extension using short Bosch EV1 connectors. I didn't realize they came in so many sizes, but the extra 1/8" I gained using the shortest version made me feel better.
The last part of the install required fabrication of a bracket to adapt the Mishimoto catch can mounting ring to the car. The aFe bracket used to attach the dual cone intake to the BMW airbox location worked well for this. All mounting hardware was secured with Loctite blue.
The result:
I'm happy with the end result, and look forward to never having to walnut blast the intake valves. The install is clean, looks nearly OE, provides easy service access to the can, and did not require any irreversible modification to the car.
