Air filtration media pack, filter element, air filtration media, and methods

An air filtration media pack is provided comprising a plurality of layers of single facer media, wherein the layer of single facer media comprising a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute 5 length extending from a first face of the filtration media pack to a second face of the filtration media pack. A first portion of the plurality of flutes are closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes are closed to unfiltered air flowing out of the second portion of the plurality of flutes so that air passing into one of the first face or the second face of the media pack and out the other of the first face or the to second face of the media pack passes through media to provide filtration of the air. At least a portion of the plurality of flutes exhibit a flute width height ratio of greater than about 2.2 or less than about 0.45, and a media-cord percentage of at least about 6.2%. The fluted sheet comprises a plurality of repeating internal peaks facing toward the facing sheet and repeating external peaks facing away from the facing sheet, said plurality of internal and external peaks comprising sharp 15 contact points with adjacent facing sheets.