INSTALLATION NOTES
(Not HowTos)

Oil Catch Can (OCC)

The controversial modification

The oil catch can rates amongst the most controversial modifications to do on a MINI Cooper S (it effects the intercooler performance, apparently.)

You can buy an OCC (for $100-$150),  or make one (for $20-$50).  The idea is to capture the oil vapors that accumulate in the engine at the valve cover, and precipitate out the oil preventing it from entering the intercooler (IC) and reducing the heat transfer efficiency of the IC.  There are various ways of installing the OCC.  After much discussion on NAM, the sketch below has emerged as the "preferred" method for installing an OCC.  An additional OCC could be added to the line between the intake tube before the throttle body (TB) and the valve cover, although this line is under little pressure there's not much room to install an OCC.

Preferred Routing for OCC

Before the general consensus emerged on the routing above, the routing below was considered an option, although current thinking has it that this may draw too much oil from the engine as the grey line from the IC produces quite a bit of vacuum.  The outlet at the left side of the valve cover has a Pressure Control Valve (PCV) in line with the tube.

Alternative Routing for OCC