Home › Forums › Stay Dirty Lounge › Engine Modifications › Air filter performance, does it work? › Air filter performance, does it work? December 2, 2011 at 11:00 am #443426 Eric Noir DyParticipant there are oiless filters as well but i find them to collect dirt. As far as CAIs sucking up water, there are bypass valves (hydropurge valves) built to go between the two pipes. it doesnt get out all of the water but it helps.