. . . "I think your response is wrong,,, yes they do use the same refineries,, but I do know that the major companies do add detergents and other additives to their product.... as far as Octane yes there is a difference not sure if that has an effect,,, and who wants to pay 20 cents plus a gallon for 88 when 86 works find,,, unless you get about 2/3 mpg sparky 17" .