What do the different octane values of gasoline mean?

Great question ! The different oct ane values of gas oline refer to the fuel ' s resistance to engine knock ing or ping ing , which occurs when the fuel ign ites prem ature ly inside the engine cyl ind ers . Oct ane is a measure of a fuel ' s resistance to det on ation , or engine knock ing . \n In general , higher oct ane fu els are more resist ant to engine knock ing and are typically used in high - per formance vehicles or vehicles that are driven under high - str ess conditions , such as racing or to wing . Lower oct ane fu els are less resist ant to engine knock ing and are typically used in standard passenger vehicles . \n Here are some common oct ane values and what they mean : \n * 8 7 oct ane : This is the most common oct ane rating and is suitable for most passenger vehicles . It provides a good balance between fuel efficiency and engine protection . \n * 8 9 oct ane : This is a mid - range oct ane rating that provides a slight improvement in engine protection over 8 7 oct ane fuel . It is often recommended for vehicles that require higher - quality fuel , such as those with high - com pression engines or tur bo charg ers . \n * 9 1 oct ane : This is a high - oct ane fuel that provides excellent engine protection and is suitable for high - per formance vehicles or vehicles that are driven under high - str ess conditions . It is also recommended for vehicles with high - com pression engines or tur bo charg ers . \n * 9 3 oct ane : This is a prem ium oct ane fuel that provides the highest level of engine protection and is suitable for high - per formance vehicles or vehicles that are driven under very high - str ess conditions . It is often recommended for lux ury or sports cars , as well as for vehicles with high - com pression engines or tur bo charg ers . \n It ' s important to note that using a higher oct ane fuel than recommended by the manufact urer will not provide any additional benefits and may actually decrease fuel efficiency . It ' s always best to consult your vehicle ' s owner ' s manual or manufact urer ' s recommend ations for the appropriate oct ane rating for your specific vehicle . </s>