2008 Subaru Impreza Owner's Manual - Page 408

GAS STATION REFERENCE & Fuel: ! Non-turbo models Use only unleaded gasoline with an octane rating of 87 AKI or higher. ! Turbo models except WRX STI Use premium unleaded gasoline with an octane rating of 91 AKI or higher. If premium unleaded gasoline with an octane rating of 91 AKI is not available, regular unleaded gasoline with octane rating of 87 AKI or higher may be temporarily used. For optimum engine performance and driveability, it is required that you use premium grade unleaded gasoline with an octane rating of 91 AKI or higher. ! WRX STI The WRX STI engine is designed to operate at maximum performance using unleaded gasoline with an octane rating of 93 AKI or higher. If 93 AKI fuel is not readily available in your area, unleaded gasoline with an octane rating of 91 AKI may be used with no detriment to engine durability or driveability. However, you may notice a slight decrease in maximum engine performance while using 91 AKI fuel. Use of 91 AKI fuel will not affect your warranty coverage. & Fuel octane rating: This octane rating is the average of the Research Octane and Motor Octane numbers and is commonly referred to as the Anti Knock Index (AKI). Refer to the "Fuel" section in this manual. & Fuel capacity: 16.9 US gal (64 liters, 14.1 Imp gal) & Engine oil: Use only API classification SM with the words "ENERGY CONSERVING" and the ILSAC certification mark (starburst mark) displayed on the container. & Engine oil capacity: 4.2 US qt (4.0 liters, 3.5 Imp qt) & Cold tire pressure: Tire size Wheel size Pressure Front Rear Temporary spare tire Size Pressure T125/70 D17 60 psi (420 kPa, 4.2 kgf/cm2) P205/55R16 89V 16 6 6 /2 JJ 1 P205/50R17 88V 17 6 7 JJ 235/45R17 17 6 8 JJ 245/40R18 18 6 81/2 J 33 psi (230 kPa, 2.3 kgf/cm2) 32 psi (220 kPa, 2.2 kgf/cm2) T135/70 D17