Fuel with an octane rating of 87 is generally considered regular, while 89 octane is mid-grade. The octane number indicates the fuel’s resistance to premature detonation, often called knocking or pinging, within an engine. Higher octane fuels are designed to withstand greater compression ratios without detonating. For example, an engine designed for 87 octane may experience engine knock if a lower octane fuel is used, whereas an engine designed for higher octane might not realize any noticeable performance improvement from using regular fuel.
The significance of utilizing the correct fuel grade lies in optimizing engine performance and preventing potential damage. Using a higher octane fuel than required by the vehicle manufacturer offers no inherent performance benefits, as the engine control unit (ECU) is calibrated for a specific octane level. Conversely, consistently using a lower octane fuel in an engine designed for higher octane can lead to decreased engine efficiency and, over time, could contribute to engine wear and tear due to uncontrolled combustion events. Historically, the development of different octane fuels was driven by advancements in engine technology, particularly the increasing compression ratios found in modern engines. This drove the need for fuels that could withstand higher pressures without premature detonation.