Originally Posted by darkrider
Does the OCC eliminate the need for walnut blasting on the N54's altogether, or does it just prolong the inevitable? Is the BMS variety the most reputable, or are there other cheaper effective solutions?
The OCC wasn't designed to eliminate the need for walnut blasting, but more to prevent oil blow through from clogging up (and reducing the efficiency) the FMIC/CP/DVs or BOV. The PCV on the N54 really doesn't seal that well, so the OCC was designed to filter out the oil vapors before they clogged up other things further down the intake tract.
The BMS OCC is the #1 OCC & the only one "approved" by Rob Beck for use with his turbos