Except STI

The engine is designed to operate using premium unleaded gasoline with an octane rating of 91 AKI (95 RON) or higher. If premium unleaded gasoline is not available, regular unleaded gasoline with an octane rating of 87 AKI (90 RON) or higher may be temporarily used. For optimum engine performance and driveability, it is required that you use premium grade unleaded gasoline.

NOTE
Be sure to use premium unleaded gasoline of 91 AKI (95 RON) or higher.

If other gasoline (lower than 91 AKI (95 RON)) is used, knocking, reduced output and poor accelerator response will result.

STI

The engine is designed to operate at maximum performance using unleaded gasoline with an octane rating of 93 AKI (98 RON) or higher. If 93 AKI (98 RON) fuel is not readily available in your area, unleaded gasoline with an octane rating of 91 AKI (95 RON) 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 (95 RON) fuel.

Use of 91 AKI (95 RON) fuel will not affect your warranty coverage.