Can 92 and 95 gasoline be mixed when refueling a car?
3 Answers
92 and 95 gasoline cannot be mixed. Here is the relevant information: 1. The higher the octane number, the stronger the anti-knock performance, which is not related to the quality of the gasoline. 2. When gasoline and air are mixed and compressed in the cylinder, if the pressure is too high, knocking may occur, causing the engine to malfunction. In gasoline, the substance that resists knocking is isooctane. The higher the octane number, the higher the isooctane content and the stronger the anti-knock performance. Therefore, whether it is 92 or 95 gasoline, the only difference is the isooctane content; the quality of the gasoline and the heat value per unit volume of fuel are the same.
As a long-time automotive technology enthusiast, I believe that mixing 92 and 95 octane gasoline might be acceptable under certain circumstances, but it's best not to do it frequently. The main difference between 92 and 95 octane lies in their octane ratings, with 95 octane offering better anti-knock properties, making it suitable for high-compression engines. If you occasionally mix them, say half a tank of 92 with 95, it might average out to an intermediate octane level, which won’t immediately harm your car in the short term. However, based on my test-driving experience, doing this long-term can easily lead to incomplete combustion, increased carbon deposits, and negatively impact engine lifespan and fuel efficiency. Modern car engines are typically designed for the recommended fuel grade, and mixing fuels may make it difficult for the ECU to adjust, resulting in sluggish acceleration or mild knocking sounds. For the sake of my car’s health, I always stick to using a single fuel grade as specified in the manual to avoid potential issues caused by trying to save money. Additionally, checking carbon deposit conditions during maintenance is crucial—it’s far more hassle-free than dealing with repairs later.
As a parent who drives daily to pick up and drop off my kids, I can understand why someone might consider mixing 92 and 95 octane gasoline—perhaps to save money or due to unavailability at the gas station. However, from a personal perspective, I recommend avoiding this practice. 92 octane is cheaper, while 95 octane is more expensive but of better quality. Mixing them might allow the car to run in the short term, but after trying it a few times, I noticed increased engine noise. Later, during maintenance, a technician explained that this could affect the efficiency of fuel injectors and spark plugs, potentially leading to higher repair costs over time. Especially for family cars, while pursuing cost-effectiveness, safety should not be compromised. I always keep an eye on the fuel consumption gauge, and when mixing fuels, the consumption slightly increases, saving little money while taking unnecessary risks. My approach is to stick strictly to the manual's recommended octane rating—for example, using only 92 octane regularly—as it's simple and reliable, avoiding the complications of averaging octane levels through mixing. If 95 octane is unavailable at the gas station, I add some fuel additives to aid cleaning and protect the engine for smoother operation during the transition.
