A filter element comprising: a filter structure having opposite first and second ends, wherein the filter structure includes a generally cylindrical inner filter pack having a filter medium, an inner periphery, an outer periphery, a plurality of axially extending pleats having pleat crests at the outer periphery of the inner filter pack, pleat roots at the inner periphery of the inner filter pack, and a pleat height that is substantially equal to or greater than the radial distance between the pleat crests and the pleat roots, and a hollow interior, a generally cylindrical outer filter pack positioned around the inner filter pack and having a filter medium, an inner periphery, an outer periphery, a plurality of axially extending pleats having pleat roots at the inner periphery of the outer filter pack, pleat crests at the outer periphery of the outer filter pack, and a pleat height that is substantially equal to or greater than the radial distance between the crests and the roots, wherein a ratio of the outer pack pleat heights to the inner pack pleat heights is about 1:0.75 to about 1:1.25 or about 1:1 to about 2:1, and a generally cylindrical helical support having first and second ends, an inner surface, an outer surface, and a plurality of support ridges and flow channels on the inner and outer surfaces extending generally helically between the first and second ends, the support ridges having a rounded or curved cross-section providing an arch-shaped configuration, wherein the helical support is positioned between the inner and outer filter packs (15; 14), the arch-shaped support ridges on the inner surface of the helical support contacting the pleat crests of the inner filter pack and the arch-shaped support ridges on the outer surface of the helical support contacting the pleat roots of the outer filter pack; first and second end caps (11; 12) attached to the first and second ends of the filter structure; a first opening in at least one of the end caps which fluidly communicates between flow channels of the helical support and the exterior of the filter element; and a second opening in at least one of the end caps which fluidly communicates between the interior of the inner filter pack and the exterior of the filter element; wherein said helical support is impermeable and non-perforated to maintain separation of the fluid flow along the flow channels on the outer and inner surfaces (20; 21) of the helical support. a filter structure having opposite first and second ends, wherein the filter structure includes a generally cylindrical inner filter pack having a filter medium, an inner periphery, an outer periphery, a plurality of axially extending pleats having pleat crests at the outer periphery of the inner filter pack, pleat roots at the inner periphery of the inner filter pack, and a pleat height that is substantially equal to or greater than the radial distance between the pleat crests and the pleat roots, and a hollow interior, a generally cylindrical outer filter pack positioned around the inner filter pack and having a filter medium, an inner periphery, an outer periphery, a plurality of axially extending pleats having pleat roots at the inner periphery of the outer filter pack, pleat crests at the outer periphery of the outer filter pack, and a pleat height that is substantially equal to or greater than the radial distance between the crests and the roots, wherein a ratio of the outer pack pleat heights to the inner pack pleat heights is about 1:0.75 to about 1:1.25 or about 1:1 to about 2:1, and a generally cylindrical helical support having first and second ends, an inner surface, an outer surface, and a plurality of support ridges and flow channels on the inner and outer surfaces extending generally helically between the first and second ends, the support ridges having a rounded or curved cross-section providing an arch-shaped configuration, wherein the helical support is positioned between the inner and outer filter packs (15; 14), the arch-shaped support ridges on the inner surface of the helical support contacting the pleat crests of the inner filter pack and the arch-shaped support ridges on the outer surface of the helical support contacting the pleat roots of the outer filter pack; first and second end caps (11; 12) attached to the first and second ends of the filter structure; a first opening in at least one of the end caps which fluidly communicates between flow channels of the helical support and the exterior of the filter element; and a second opening in at least one of the end caps which fluidly communicates between the interior of the inner filter pack and the exterior of the filter element; wherein said helical support is impermeable and non-perforated to maintain separation of the fluid flow along the flow channels on the outer and inner surfaces (20; 21) of the helical support.