Thes filters are marketed as Mad Duc here in the States.
Maybe the best way to answer your question is to go to their web site and review the their marketing presentation.
They state: “We designed this air filter system by having these critical issues in mind:
Best Air Flow Maximum Air Circulation in the Air Box (All after market filters consume a large volume of the air box.)”
Critique: They state their filter has the best air flow maximum air circulation IN THE AIR BOX and mention that other AFTERMARKET in-the-air box filters take up more volume. The stock filter is outside the air box so it obviously has better “air flow maximum air circulation in the air box.” Notice that they don’t claim that their device has lower air flow restriction than the stock filter. It doesn’t.
“Complete Sealing of the Air Intake Bell Housing From Outside Elements ( Reducing the chance of engine ceasing in case of a crash by sucking in gravel.)”
Critique: We can give them this: IF you crash, AND the gas tank becomes dislodged from the air box breaking the seal, AND gravel gets into the air box this device will prevent engine ingestion and further damage caused by the crash. Your insurance company will thank you.
“Quick and Easy Change and Cleaning Procedure (Raise the gas tank and snap the filters over the bell housings.)”
Critique: This is good. Given the tiny filter element you’ll be doing this a lot.
“No Distortion at High RPM (Most available filters cave into the bell housing at higher RPM.)”
Critique: The stock filter doesn’t.
“And Finally, More Horse Power, More Horsepower, More Horsepower…. “
Critique: At Last, Good, Good, Good…. (but show us the dyno charts comparing it with the stock filters and any others for that matter). To be fair, they don’t really say that their devices will actually give you more horsepower, they simply say that they designed “having these critical issues in mind.”
One more point (that they fail to mention as a design objective): Show us that the device is actually a FILTER by some information about the particulate size it stops relative to the stock filter or any other competing aftermarket filter.
PS. Next time you're doing some dyno work, place your finger near the top edge of one of the velocity stacks and watch the power output drop-off big time. This is absolutely the worst place to place a filter because it turns laminar (smooth) airflow into turbulent flow.
Posted comments from owners:
"Those filters suck! I have no idea why, but I have witnessed, with my own eyes three different dyno runs on the same bike (race only 996) and the difference between those mushroom filters and a FBF filter was about 10 rwhp.
The bike belongs to Ben Fox at
http://www.foxperformanceengines.com/. He also could not figure out why those little filters would rob so much power but the bottom line is that they do. We tested a Pipecross filter on my friends 998 and the difference with the filter and without a filter was less than 1 hp." mr.duc
David Vizards book "Tuning BL A series engines" its well worth a read. He did a whole series of flow bench tests whith various configurations of flat edges, radius etc and it clearly shows that the shape at the edge of the intake is critical to the airflow peformance." rockhopper
Caveat emptor.
skidlids
Shazaam!
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