If you read the sales blurb in the catalog for the "Super Premium" 5 micron filter, they now indicate that it is for all '99 and up Twin Cams, BUT it can also be used as an upgrade for the older EVO filters. That's a different story than what they were putting out many years back, when they obviously still had a big inventory of the EVO filters on hand that they wanted to sell. The obvious difference in the new filter is the micron rating and the use of more modern synthetic media (filtration material). The old style treated paper is still a good filtration media, so I wouldn't let that influence my decision. The big difference is the micron rating. H-D never made it known what the old filters were rated at, but the consensus seems to be they were in the 20 to 30 micron range that was typical of that period. Is a 5 micron filter going to filter better? Depends on how often the filter bypasses due to internal pressure buildup. Common sense would say a finer filter would be more likely to start plugging up quicker and thus cause the bypass to open. If that occurs, the finer filter could in fact cause more dirt to stay in the oil. Without side by side testing I don't know how we can really determine which is "best".
BTW, sadunbar offered the best advice, go with the K&N filter. The KN-170C (or B if you want black) is the correct part number for an EVO.
Jerry
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Topic: Correct Oil Filter FXR4 (Read 1608 times)