This is a Purflux L358A cartridge filter, sold in a Mini branded box at American Mini dealers. It was in use for 5153 miles and about two and a half months. I used Castrol Edge 0W-30 European Formula for this whole interval. I sampled the oil at this change but I don't have the results back yet. As you can see the filter looks really great. No collapsing, no holes, no metal or grit in the media. The media was very strong, in fact it was difficult to cut with my utility knife.
I was curious how much of a size difference the zig zag pleats made, so I did a bit of measuring. The entire filter height, including the plastic end caps, is 2.75 inches. When I cut the filter media out and stretched out the zig zags, the filter media measured 3.75 inches. So that's 1 inch more media than the entire size of the filter, and if you subtracted another half an inch or so to account for the thickness of the end caps, then it's probably on the order of 1.5 inches more media (in that direction) than a non zig zag filter. The length of the media was 37 inches, which gives us 138.75 square inches of media. The same size filter without zig zag pleats would have a media surface area of 83.25 square inches.
I was curious how much of a size difference the zig zag pleats made, so I did a bit of measuring. The entire filter height, including the plastic end caps, is 2.75 inches. When I cut the filter media out and stretched out the zig zags, the filter media measured 3.75 inches. So that's 1 inch more media than the entire size of the filter, and if you subtracted another half an inch or so to account for the thickness of the end caps, then it's probably on the order of 1.5 inches more media (in that direction) than a non zig zag filter. The length of the media was 37 inches, which gives us 138.75 square inches of media. The same size filter without zig zag pleats would have a media surface area of 83.25 square inches.