Originally Posted By: ZeeOSix
Originally Posted By: CharlieBauer
Which makes it all the more weird that Mann publish oil filter efficiencies according to 16889.
Apparently to the catalog, Mann has ran a multi-pass test but say it's defined in ISO 4548-12 test but calibrated to ISO 16889 - whatever that means. ISO 16889 is also a multi-pass test, so not sure why they are even mentioning ISO 4548-12. IMO, it basically just means ISO 16889 was ran with some kind of 4548-12 morphing. Talk about confusing.
See Mann catalog pages 10 and 111 (snipped and shown below). Also see the asterisk footnote at the bottom of the table:
"
* In comparison to the previously used calibration, the new calibration with the same filter results in a lower filter fineness with small particles."
So whatever the actual differences between the two test methods, it had an effect on the resulting efficiency measurement, as indicated in their footnote. Sounds like ISO 16889 gives a lower efficiency result - by how much, who knows? - they don't say. So comparing an efficiency per ISO 4548-12 to ISO 16889 is obviously not an apples-to-apples comparison. Mann is a Euro company, so don't know why they would use ISO 16889 for auto spin-on filter testing when ISO 4548-12 is specifically designed for testing those types of oil filters.
Good finding. I was looking for some of that info. It looks like the calibration had changed recently according to the small text at the bottom of the first screenshot. Based on these results, I think we should all be able to agree that these are not apples to apples comparisons to the performance numbers that Fram puts out. I find it extremely hard to believe a company that "just" specializes in filtering could have performance numbers this bad in comparison to whatever we can get off the shelf at the local auto supply store. Why in the world would an auto manufacturer like Mercedes, BMW, Volvo, VW (Audi) select such a poor performing filter if they can produce numbers near competing (cheaper) products.