2008 Mazda RX-8 Owner's Manual - Page 116

Before Driving Your Mazda Fuel and Engine Exhaust Precautions Fuel Requirements Vehicles with catalytic converters or oxygen sensors must use ONLY UNLEADED FUEL, which will reduce exhaust emissions and keep spark plug fouling to a minimum. Your Mazda will perform best with fuel listed in the table. Fuel Premium unleaded fuel Octane Rating*(Anti-knock index) 91 [ (R+M)/2 method] or above (96 RON or above) * U.S. federal law requires that octane ratings be posted on gasoline station pumps. This vehicle is designed to use 91[ (R+M)/2 method] (96RON) or higher gasoline for best performance. If 91[ (R+M)/2 method] (96RON) is not available, gasoline from 87 to 90[ (R +M)/2 method] (91 to 95RON) can be used temporarily for emergency purposes, but this will slightly reduce performance. Fuel with gasoline from 87 to 90[ (R+M)/2 method] (91 to 95RON), driving in high temperature or low humidity conditions could cause engine knocking. Fuel with a rating lower than 87[ (R+M)/2 method] (lower than 91RON) could cause the emission control system to lose effectiveness. It could also cause engine knocking and serious engine damage. CAUTION Ø USE ONLY UNLEADED FUEL. Leaded fuel is harmful to the catalytic converter and oxygen sensors and will lead to deterioration of the emission control system and or failures. Ø Your vehicle can only use oxygenated fuels containing no more than 10% ethanol by volume. Damage to your vehicle may occur when ethanol exceeds this recommendation, or if the gasoline contains any methanol. Stop using gasohol of any kind if your vehicle engine is performing poorly. Ø Never add fuel system additives. Never add cleaning agents other than those specified by Mazda. Other cleaning agents and additives may damage the system. Consult an Authorized Mazda Dealer. Gasoline blended with oxygenates such as alcohol or ether compounds are generally referred to as oxygenated fuels. The common gasoline blend that can be used with your vehicle is ethanol blended at no more than 10%. Gasoline containing alcohol, such as ethanol or methanol, may be marketed under the name "Gasohol". Vehicle damage and drivability problems resulting from the use of the following may not be covered by the Mazda warranty. l Gasohol containing more than 10% ethanol. l Gasoline or gasohol containing methanol. l Leaded fuel or leaded gasohol. 4-2