Originally Posted by bigbadandugly
The high-flow BMC air filter provided no performance gains to the subject motorcycle. In fact, of the 20+ runs we did, only two were with the stock filter and it was one of these runs where the bike achieved 111 rwhp. If you're buying the filter for its reusability and wet weather utility improvements over the OEM paper filter, then you're buying it for the right reasons. If you've drank the Kool-Aid and are buying it to give you increased power, you've been suckered.
4) The airbox snorkel appears to be an integral part of the air intake design. Out of curiosity, we removed the snorkel, thinking it may restrict air flow through the already quite small air filter. We did two runs and both were in the 105 rwhp range, down 5-6 rwhp from our high run.
The BMC is no different then a K&N, which has been tested against paper and Uni Filter AUS foam to flow over 50cfm less then the Uni on a flow bench. I've also tested the Uni on R1200GS SIHC bikes with full exhaust systems and a tuner, the Uni did provide up to 3 additional rwhp with stock snorkel.
WL offered a "big mouth" snorkel for the Boxers, however I have not seen it of late and not dyno tested myself.
Also your dyno of choice is very generous as most dynojets around these parts put a stock R1200GS DOHC in the 90-94 rwhp stock with up to 104 after full Akra, PC V and Unifilter.