I've heard of this but never tried it.
"How Much to Use
Add in tiny amounts from about one part per 5000 to one part per 3000, depending on the vehicle -- just a few ounces per ten gallons of gas. This comes to between 0.0003 % to 0.0025 % acetone maximum or approximately 1/15th of one-percent. Note that is around .78 cc per liter or one ounce per 10 gallons. Not more than three oz. per 10 gallons."
http://www.pureenergysystems.com/new...00069_Acetone/