for all the guys running an older motor or a newer one for that matter and want a cheap octane booster try xylene.2 oz. per gallon turns regular into premium.I work at a paint store and I have been using it for about a year now with great results.xylene is cheap if you go to the right place and if you read the ingredients on a bottle of "104 octane booster"it is mostly xylene.buy premium add 2 oz. per gallon and hold on.it really works.my mileage went from 11 mpg to almost 15 to boot!!