I used to run 87 exclusively with a can of SeaFoam every other tank. I now run 93 with no SeaFoam. I haven't noticed anything from a power loss/gain perspective. The fuel economy has "increased". But, that's like going from 10.8 to now 11mpg. Kind of thinking of going back to 87 frankly and do SeaFoam every 3-4 fill-ups.
One thing I have noticed though, I get better performance and range with certain brands. Sunoco is the best for me followed by Valero and Chevron. Shell, Texaco and Exxon have been the worst for me. Those last 3 routinely result in sub 10mpg. Sunoco invariably averages around 11. Been tracking performance for nearly 3 years and 90k miles.
One thing I have noticed though, I get better performance and range with certain brands. Sunoco is the best for me followed by Valero and Chevron. Shell, Texaco and Exxon have been the worst for me. Those last 3 routinely result in sub 10mpg. Sunoco invariably averages around 11. Been tracking performance for nearly 3 years and 90k miles.