A dispersant that is a reaction product of a polyalkenyl-substituted mono- or dicarboxylic acid, anhydride or ester; and a polyamine, wherein the reaction product has from greater than about 1.3 to less than about 1.7 mono- or di-carboxylic acid producing moieties per polyalkenyl moiety, and the polyalkenyl moiety has a number average molecular weight of at least about 1800, and a molecular weight distribution (Mw/Mn) of from about 1.5 to about 2.0.