That is an intruiging subject about which I was ignorant, so: Doing a search for information I found a spec sheet for NAPA filter 3032 (33032 Wix number) showing it at 20 microns. The filter element is paper (cellulose). That sheet said they are standardizing on the Wix brand for future stock. It seems to be all metal rather than plastic body construction. Principle applications are agricultural and construction equipment, which should qualify it for your expected dirt conditions.
It appears that filter you have been using should be adequate, if not more than technically needed to protect the fuel pump. Mike S might chime in on this topic since he has flown that airplane a long time. George -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus -- KRnet mailing list KRnet@list.krnet.org https://list.krnet.org/mailman/listinfo/krnet
