What is the difference between 92 and 95 octane?
2 Answers
The difference between 92 and 95 octane gasoline lies in their anti-knock properties. Below are the specific reasons for the difference between 92 and 95 octane gasoline and their anti-knock properties: Standard gasoline primarily consists of isooctane and n-heptane. Isooctane has good anti-knock properties, with its octane rating set at 100; n-heptane has poor anti-knock properties and is prone to knocking in gasoline engines, with its octane rating set at 0. If the gasoline is labeled as 92 octane, it means that this grade of gasoline has the same anti-knock properties as standard gasoline containing 92% isooctane and 8% n-heptane; if the gasoline is labeled as 95 octane, it means that this grade of gasoline has the same anti-knock properties as standard gasoline containing 95% isooctane and 5% n-heptane. The higher the octane rating, the stronger the anti-knock properties. Anti-knock properties refer to the ability of gasoline to resist knocking when burned in an engine, which is a key indicator of gasoline's combustion performance. Abnormal combustion of gasoline in an engine can cause knocking.
I'm an ordinary car owner with over ten years of driving experience, often torn between using 92 or 95 octane fuel at the gas station. To be honest, 92 octane is much cheaper, saving me dozens of yuan each fill-up. However, my older car sometimes makes a strange 'knocking' sound, which the mechanic said was caused by engine knocking due to the high compression ratio and using lower anti-knock fuel. After switching to 95 octane, the engine became noticeably quieter and ran smoother, thanks to its higher octane rating, which can withstand greater pressure. That said, using 95 octane didn’t significantly improve fuel efficiency, and it costs more. For most daily-use family cars, the owner’s manual recommends 92 octane as sufficient; sports cars or turbocharged vehicles are better off with 95 octane to avoid engine damage. Remember to change the oil and check the engine regularly—don’t compromise your car’s health to save a few bucks, as the difference can have a significant impact.
