Abstract: An efficient and cost competitive fuel extender for mixing with lead-free gasoline used for driving internal combustion engines is provided which makes use of low grade, inexpensive naphtha as its principal ingredient that is upgraded in combination with anhydrous ethanol, toluene, aromatic benzene, xylene and a class of stabilizing and water repellent chemicals, all in a critical range of content. Its synergistic content provides a resultant product that is usable as a compatible additive for lead-free gasoline; it is extremely low in cost, and does not require any engine adjustments or fuel line protection measures; it may be provided with either a so-called regular or "MID" grade octane rating.