I think I posted this years ago when this type of subject came up. I questioned the micron rating of the CAV filters that most of us use and Wix says their filter is 10 micron (part # 33166) and Lucas/Delphi claims theirs (part # 7111-296) is 5-7 micron. Wix techs dispute Lucas... Probably Racor would have their own spin on the subject.. Below are the emails I received FYI. Good luck, Phil (Contact From WIXFILTERS) >Our 33166 part number is a direct cross reference to the Lucas 7111-296 > part number. This is the same part number used by C.A.V. who invented this > type of filter. Their filter contains media that is rated at 10 micron > like ours. It does not have 2 micron media. A particle that is 1 > micrometer (micron) in diameter is .000039" across. The average human hair > has a diameter of 70 microns and the human eye can not see anything under > 40 microns without magnification. The difference between 2 and 10 microns > is measurable in the lab but is real life it makes very little, if any. > performance difference. > > Thank you for your inquiry. > > Chris Greeson > Technical Service Representative (Contact from Lucas/Delphi) > The Delphi HDF296 has a micron rating of between 5-7 micron (average > contaminant size in testing is 6.9 micron). Its average retention is not > less than 85% and is normally around 95%. The rolled paper-type design of > the filter was pioneered by Delphi, and it still remains the benchmark for > this kind of filter. > > I hope that this answers your question, and if you have any further queries, > please do not hesitate to contact me. > > Kind regards > > Ian Girle > Product Manager > Filtration

When I talked to Bob Smith a couple of years ago, we discussed these filters. While he approves of Wix for oil filters and such, for some reason he doesn't think much of the Wix version of the CAV filter. It is a different type of filter media, so I guess it sort of makes sense to me. When I bought my boat 5 years ago, I let the PO tell me what filters I needed for the delivery trip, and for some unknown reason he had me buy 24 Wix filters for the engine! It has taken me all this time to use up my "stores" of these filters, and when I do, I'll either do the adapter thing and go to a spin on, or I'll go to using the Delphi brand. A bonus is that at the local O'Reily's the Wix 33166 is $7.49 and the Delphi from AD is $6.25. Buy 8 or so at a time and with freight they will be about the same price and you save sales tax. Brent Hodges