Most of Gulf Coast submicronic bypass filters go to the US government to reduce waste of natural resources. They are used mostly by USAF and US Army National Guard. Cape Canaveral has been ordering the Gulf Coast filters on new equipment factory installed. North Carolina has Gulf Coast filters on all of their ferry boats. Shell oil uses a lot of them on offshore rigs. General Motors is factory installing the GM - 01 part # 1507 1671 when the government requires them.
I brought back the Motor Guard submicronic bypass filter of Manteca California. It's my personal favorite small filter. They have been around since 1966. I like to use it with the PermaCool sandwich adapter. The Motor Guard is the easiest to change of the TP filters. I change it every 4,000 miles on my Camry and Subaru 4 cylinder cars. The Camry uses synthetic, the Subaru uses conventional.
You can go farther between changes with synthetic oil if you don't mind a higher wear rate. When I started using the Frantz in 1963 we didn't have synthetic oil. We managed somehow to get by
Multi grade oils were no good in those days. We used single wt oil. We didn't drain oil. We changed the toilet paper and added a qt of oil every 2,000 miles.
You might find the following interesting:
"EnviroSense
Department of Defense
Pollution Prevention Technical Library
Bypass Filter for Vehicle Motor Oil Introduction:
Gasoline and diesel fueled internal combustion engines require
lubricating oil to reduce friction and dissipate heat. The lubricating oil must be changed once the oil's effectiveness diminishes. Lubricating effectiveness generally does not deteriorate in high-quality oils, but what does occur is contamination of the oil with particles and a breakdown of the
lubricating oil's additive package. The additive package, which can be 50 percent of the oil's volume is responsible for maintaining pH and preventing deterioration of the oil. Bypass filters are designed to remove smaller particulate than would normally be removed by the engine's normal filter so that oil changes are not necessary. Oil added during filter changing, and to replace burned oil, is normally sufficient to replenish the oil's additive package."
Ralph