I Disected K&N, Perf-form and HD 10 micron filters, see attached pictures.
A couple of things I observed:
1. The HD filter has the smallest amount of filter media.
2. The K&N has a rubber relief valve where the HD has a fiber one (which would seem to me it might leak). Not sure yet about Perf-form it is totally different design.
3. The HD has the least amount of threads for the screw on base.
4. The HD has the most pliable anti drain back rubber(feels like silicone).
5. The K&N has a well formed spring that seals the element to the drain back rubber, the others look nasty at best. I don't think this is a big deal though as they all had pressure on the elements when cut apart.
6. Filter sealing rubber gaskets all are same size and shape. HD crimps thiers in the others are just snug fits.
A couple of things I observed:
1. The HD filter has the smallest amount of filter media.
2. The K&N has a rubber relief valve where the HD has a fiber one (which would seem to me it might leak). Not sure yet about Perf-form it is totally different design.
3. The HD has the least amount of threads for the screw on base.
4. The HD has the most pliable anti drain back rubber(feels like silicone).
5. The K&N has a well formed spring that seals the element to the drain back rubber, the others look nasty at best. I don't think this is a big deal though as they all had pressure on the elements when cut apart.
6. Filter sealing rubber gaskets all are same size and shape. HD crimps thiers in the others are just snug fits.