I think the facts are pretty clear. A good bypass filter system in addition to a normal full flow filter system will double your engine life.Valves, seals, piston rings, cams, lifters,bearings, and timing chains. This has all been tested to death on deisels. You say diesels are dirtier than gas engines? Look at the sump capacity of the diesels they test,12-24 gallons. They actually run diesels at considerably lower contamination levels than gasoline engines with their 4 quart sumps.I have been testing the Frantz bypass filters and reading all the SAE literature I can find. These things simply work. I have no idea why they are not more popular, or why I never heard of them before BITOG.