Just got off the phone with Ford Racing. I had him read me the detail since he did not understand micron, LOL!!
OK the FL-1HP has been replaced with the M-6731FL-1A, so the ford racing hp filter has the added nomenclature of M-6731 and onlly available through Ford Racing not motorcraft.
The FL-1hp or m-6731FL-1a are both the same and have a multipass rating of 99% for 20 micron!!!!!!!!!!!!!!!!! Now that being said usually ratings are single pass, what they are saying is after multiple passes you will filter anything over 20 micron 99%of the time. It also has a
synthetic media which is an upgrade over the fl-1a.
Bottom line is the FL-1Hp is 20 micron, more pleates and is a better filter, is it $12.00 better I have no clue. The bypass rating is 17-23 psig. Old HP was 22 psig which falls in the range.
My
oil pan was so clean when I removed it had to be filtering.