Can You Add 95 Octane Gasoline After Using 92 Octane?
2 Answers
If the user manual indicates that the minimum octane rating required is 92, then using 95 octane gasoline is acceptable. However, if the manual specifies 95 octane gasoline, you should not use 92 octane. Below are some relevant details: 1. The primary difference between 92 and 95 octane gasoline lies in the ratio of heptane and isooctane. 92 octane gasoline contains 92% isooctane and 8% heptane, while 95 octane gasoline contains 95% isooctane and 5% heptane. 2. The octane rating does not reflect the purity or quality of the gasoline. In fact, the octane number only indicates the gasoline's resistance to knocking and has little to do with its overall quality. If your car can use both 92 and 95 octane gasoline, it is not recommended to alternate between different octane ratings, as this may adversely affect the engine. It is best to consistently use one type of octane gasoline.
Last time when my car was almost out of gas, the 92-octane pump at the gas station was under maintenance, so I directly filled half a tank with 95-octane. Actually, mixing gasoline isn’t a big issue. The main difference between 92 and 95 is the octane rating and anti-knock performance. 95 has better anti-knock properties, but your car originally designed for 92 has an engine compression ratio tailored for 92. After mixing, the system can automatically adjust the ignition timing to adapt, so it won’t harm the engine. It’s fine occasionally, just remember not to mix them long-term, otherwise fuel consumption might increase by about 0.5, and more deposits may accumulate in the tank. The safest approach is still to follow the fuel grade recommended in the manual, as manufacturers have tested it over tens of thousands of kilometers before making the recommendation.
