Compression Ratio 11:1, Should I Use 92 or 95 Octane?
2 Answers
For a compression ratio of 11:1, it is generally recommended to use 95 octane gasoline. The differences between 95 and 92 octane are as follows: Different main components: Analyzing the main components of 95 and 92 octane gasoline, 92 octane consists of 92% isooctane and 8% n-heptane, while 95 octane is composed of 95% isooctane and 5% n-heptane. The reason 95 octane is slightly more expensive is due to its higher proportion of isooctane. Different functions: Isooctane also has another function, which is anti-knock. This means that the higher the proportion of isooctane, the better the anti-knock performance. Every engine undergoes a comprehensive evaluation before leaving the factory, and based on the engine's performance and other data characteristics, anti-knock requirements are specified, which determines the recommended octane rating of gasoline to be used.
For an engine with an 11:1 compression ratio, I recommend prioritizing 95-octane gasoline. The high compression ratio means greater cylinder pressure. If you use 92-octane fuel with lower octane rating, the engine may experience knocking—that rattling or pinging sound—which can severely damage pistons or spark plugs. I've driven a car with a similar engine, and switching to 95-octane made it run much smoother, with reduced noise and more responsive throttle. Higher octane fuel provides better anti-knock performance, preventing long-term damage. In terms of fuel consumption, 95-octane burns more efficiently, so the overall cost difference isn't significant. Safety tip: Check your car's manual for recommended fuel grade. If unsure, 95-octane is the safer choice.
