We tested 2 gas engine lubricants from different oil suppliers, and they seem to performed differently under test conditions and operation conditions. N°1 has twice as much dispersants (measured by nitrogen content) than N°2, and have much less oxidation results in the lab (measuring viscosity increase at 400 °F, for 24 hs) - 111% vs 675%. This could be explained due to base oils (N°1 is a group I&II mix vs N°2 full group I, both no broght stock).
But the odd part is that in the field we see higher viscosity and oxidation increases in oil N°1 (with same oil concumption levels). Could this be due to the difference in dispersant content? I mean, the dispersant is keeping soot in suspension (soot was not present in the lab test, of course) and this ends up in higher viscosity & oxidation increases? Is this reasoning possible?