i did the same, buying 6 cases and used them on all my gas cars, including my antiques. they all improved mpg significantly and ran a lot better. i can not explain why you did not show improvement, but, i certainly did. i later added bishops original to the oil, which fuses to the metal, and added even more improvement to mpg. i used dynamo in 5 gas engines, mbz slk230, toyota tundra, model A ford (2), smart car. i also added dynamo for a diesel engine, to my 1979 mbz 300D and had similar improvements in mpg and ended the smoke out the tail pipe. i reported on all of these several years ago, on ihub here.