Is 95 Octane Gasoline More Fuel-Efficient Than 92 Octane?
3 Answers
Using 95 octane gasoline is relatively more fuel-efficient and durable compared to 92 octane. The higher the fuel octane rating, the slower the combustion speed, the lower the combustion knock, and the higher the engine compression ratio required, with the ignition timing needing to be advanced. The opposite is also true. When the engine has a high compression ratio, high-octane gasoline should be used. If low-octane gasoline is used in a high-compression engine, it can cause abnormal combustion, leading to knocking, increased fuel consumption, and reduced driving power. Simply follow the manufacturer's requirements for refueling. Differences between 92 octane and 95 octane gasoline: In terms of n-heptane content, 95 octane gasoline contains 5% n-heptane, while 92 octane gasoline contains 8%. In terms of isooctane content, 95 octane gasoline contains 95% isooctane, while 92 octane gasoline contains 92%. Regarding anti-knock properties, different gasoline octane ratings indicate different fuel anti-knock capabilities. The higher the octane rating, the better the anti-knock performance. 95 octane gasoline has better anti-knock performance than 92 octane gasoline.
This question has been asked by many, and I think the answer depends on the situation. Last year, I drove a car that used 92-octane fuel and specifically tested the fuel consumption after switching to 95-octane. Records over two consecutive months showed that on the highway, 95-octane saved about 0.2 liters per 100 kilometers, but there was no difference at all in city traffic jams. In reality, 95-octane fuel isn't more fuel-efficient; its calorific value is similar to 92-octane. The difference lies in the fact that engines with higher compression ratios burn more stably, avoiding knocking and thus utilizing fuel more efficiently. Like I've tried with different car models, now I only refuel according to the manual's recommendations. The key to saving fuel still depends on the car's condition and whether driving habits are smooth.
From the perspective of fuel characteristics, the burn duration difference between 95 and 92 octane gasoline is minimal. I recall testing data showing both fuels have a calorific value fluctuating around 44MJ/kg. The notion that 95 octane burns longer might be a misconception—its higher octane rating primarily prevents engine knocking, especially in high-compression engines. During my tests with turbocharged engines, I did observe more stable performance and slightly lower fuel consumption with 95 octane, but the effect was negligible in older low-compression vehicles. Using the wrong grade long-term may actually increase carbon deposit risks. For daily commuting in standard sedans, sticking with 92 octane is perfectly adequate and economical.
