Originally Posted by Farnsworth
Nice to learn the efficiency ratings on the Boss and others. Since the test is run till loading, it tests the media, it doesn't really matter what filter model is tested. Efficiency is stated as a %. I would like to see all the many red cans that have torn media reposted since that has been said. Not sure that's true or a rumor. I think maybe the Classics were showing tears and someone vocalized it means the red ones must tear too. Then it becomes they all tear.
You've been here long enough (under at least 3 usernames) to know the history of the Purolator tearing issue. Both the old Classic and PureOne showed media tearing ... their full synthetic didn't.
As far as the ISO efficiency test, the size of the filter used in the test can certainly have a bearing on the resulting efficiency. As has been shown, oil filters can lose efficiency as they load up due to captured particles shedding off the media from increased delta-p. A filter with a much higher media area will reduce the delta-p across them media which will reduce captured particle shedding, and that will result in better efficiency. The two smallest Purolator filters in the same line with the same media had an advertised efficiency lower than the rest of the larger filters (ie, they were 99% @ 40u vs 99% @ 20u of the larger filters). It was printed right on the box, but never shown on Purolator's website. Sayjac (along wth others here) know what I'm referring to - I was discussed quite a bit a few years ago.
I think Fram is the only filter maker that shows efficiency numbers based on the average of 3 different sized filters, which helps take out the size factor of the filter in the advertised efficiency.