Hi,

After doing a lot of research, w/o finding any "REAL'" detailed installation of a John Cooper Works (JCW) Performance Kit Air Box, w/the Cone Filter, on the N18 engine, I decided to write one here.

I just did the installation, and took photos.

The JCW Performance Kit uses the Cone Filter, while the one used in the MC w/the JCW Package, as well as the GP, are said to use Flat Filters. The Cone Filters are say to flow better than the Flat ones, from what I've read.

The JCW Air Box is design for the N14 Engine, and sadly not the N18. There's some interference from the HPFP on the N18, which is different on the N14.

Things which you need for the installation:
1. The Lower Portion of an Air Box from an N14 engine. The Lower Portion of the Air Box from an N14 engine fits w/no problems at all on the N18. It's held in place on the engine w/some rubber grommets. Make sure you don't lose them, because they can easily come out.
2. The John Cooper Works Air Box from the Performance Kit, w/the Cone Air Filter.
3. A gasket, used on the Lower Air Box for Sealing the JCW Air Box.
4. Aluminum Tape. The thinner Tape is easier to form over the ground out area.
5. A small round piece of plastic, used for rubbing down the Aluminum Tape in order to remove bubbles and such.
6. A Dremel Tool, for grinding the Air Box.




Stock 2013 MC S Air Box




2013 MC S w/the JCW Air Box




2013 MC S w/the JCW Air Box





N14 Engine Lower Air Box w/Required Gasket for the Upper JCW Air Box. To the right of it, is the High Pressure Fuel Pump (HPFP), which is the clearance issue w/the JCW Air Box. I'll be replacing the Lower Air Box w/a new one, due to a stripped mounting hole, and a broken tab, but it'll work in the mean time.


As you can see here, there is a clearance issue w/the HPFP. You need to marked it as best as you can, and pull the JCW Upper Air Box in order to grind it. The Upper JCW Air Box isn't seated on the Lower N14 Air Box, so the grinding slot tends to move to the left as the Upper fits better. It's takes a little time to mark, take off, and grind, till the Upper Top is finally seated onto the Lower. Once done, you want to grind a little more for a little clearance, for the Aluminum Tape.


As you can see, you can remove this piece from the JCW Upper Airbox for easier grinding. Anyway, once completed I went and used Aluminum Tape in order to seal the Air Box. I used four (4) layers, rubbing each layer w/a small round plastic piece. to removing air pockets and such. I don't know if this will hold up to the heat of the engine, we'll see.


Here's the inside of the taped opening.


Here's the whole JCW Air Box assembled.


Another view of the completed assembly.


Here's it assembled.


Here's another view of the assembly, relative to the HPFP. It barely clears, due to the Aluminum Tape. I'll be checking on both and how the Tape holds up to the heat of the engine, and well as any contact wear, if any, next time I disassemble things.

The ground out area shouldn't need to be that big, but once again, the Upper JCW Air Box wasn't fully seated, and so as I ground down the area, the top would seat better, as well as the contact area tended to move as well, because of it. If you had a 3D Scan Model of that piece, you could use a 3D printer to make a 3D Plastic Model of it w/the slot molded in w/o the need of the Aluminum Tape.

I'll be replacing the Lower Air Box w/one in better shape than the one I used. One of the mounting holes is stripped, as well as one of the Tabs in the back is broken.

I hope this helps others interested in adding a JCW Air Box on an N18 Engine.

Finally, I took a quick spin, and it felt a little more powerful, it's hard to say. I went and passed someone on the local expressway, then suddenly noticed, that I was running well over 100 MPH, in 6th gear no less, w/o downshifting or anything, nor feeling any load on the engine. Last time that ever happened to me, I was driving a Porsche.

By the way, I also have the JCW Exhaust installed as well. I kept the Resonator installed because it would of been too loud for me. I got a excellent deal on the JCW Performance Kit, minus the software, for a very good price. Someone bought the kit, but only needed the software.


JCW Exhaust