Fuels splash octane

Octane ratings  

Understanding octane ratings.

About octane ratings

Octane rating is a measure of a fuel's ability to resist ‘knock’. The octane requirement of an engine varies with compression ratio, geometrical and mechanical considerations and operating conditions. The higher the octane number the greater the fuel’s resistance to knocking or pinging during combustion.

The octane ratings of Exxon- and Mobil-branded Synergy™ gasoline

  • Exxon and Mobil Regular Unleaded Octane 87
  • Exxon Plus and Mobil Special Unleaded Octane 89
  • Exxon Supreme and Mobil Super+ Unleaded Octane 91-93


The right octane level for your vehicle

The recommended octane rating for most vehicles is usually octane 87, but be sure to check your vehicle owner’s manual. Ordinarily, a vehicle will not benefit from using an octane higher than recommended in the owner’s manual. However, some car models have high-compression engines and electronic controls, which are designed to benefit from the greater power output and improved fuel economy of high octane fuel. Since octane requirements can vary with operating and environmental conditions, your vehicle may need a higher octane fuel than recommended to prevent knocking.

Have a question about octane ratings?

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**Fuel economy improvement is based on Synergy-branded gasoline compared to gasoline meeting minimum U.S. government standards. Actual benefits will vary based on factors such as vehicle type, driving style and gasoline previously used. Exxon, Mobil and Synergy are trademarks or registered trademarks of Exxon Mobil Corporation or one of its subsidiaries.
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