Abstract: A neutral oil soluble organosulfonic acid ammonium salt formed by reaction of C.sub.1 -C.sub.26 sulfonic acid with a nitrogen base chosen from the group consisting of mono-, di-, and tertiary amines, acid addition salts of such amines, or quaternary ammonium compounds, the nitrogen base having at least one hydrocarbyl group containing from about C.sub.1 to C.sub.36 carbon atoms, is added to an oil composition to improve the load-carrying capacity of the oil composition. The sulfonic ammonium salts are particularly effective in synthetic ester lubricants used in turbine engines. The oil compositions of this invention are also compatible with the silicone and fluorosilicone seals used in such engines.