Subaru Impreza Quiz
Starting and operating

Fuel octane rating

In this manual: Starting and operating
Foreword — 1Warranties — 5How to use this Owner’s Manual — 5Vehicle symbols — 1Safety precautions when driving — 14Illustrated index — 7Function settings — 1Seat, seatbelt and SRS airbags — 75Keys and doors — 66Instruments and controls — 121Climate control — 42Audio — 168Interior equipment — 29Starting and operating — 111Driving tips — 31In case of emergency — 21Appearance care — 16Maintenance and service — 109Specifications — 21Consumer information and Reporting safety defects — 31
~1min read

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).

Using a gasoline with a lower octane rating can cause persistent and heavy knocking, which can damage the engine.

Do not be concerned if your vehicle sometimes knocks lightly when you drive up a hill or when you accelerate. Contact your SUBARU dealer if you use a fuel with the specified octane rating and your vehicle knocks heavily or persistently.

Test yourself

A quick Subaru Impreza quiz: every answer comes with an explanation and a link to the manual page.