Can 98 gasoline be replaced with 95?

[StDallas]

No. Generally speaking, it is acceptable to slightly increase the fuel grade above the minimum standard, as this can better optimize vehicle performance. Below is an introduction about gasoline octane ratings: 1. Concept: The current market offers gasoline with octane ratings such as 90, 93, 95, and 97. These numbers represent the octane rating of gasoline, indicating its anti-knock properties, and are unrelated to the cleanliness of the gasoline. 2. Selection of octane rating: During the design phase of an automobile engine, the octane rating of the fuel to be used is determined based on the compression ratio. The compression ratio is a very important structural parameter of the engine, representing the ratio of the gas volume when the piston is at the bottom dead center at the start of compression to the gas volume when the piston is at the top dead center at the end of compression. From the perspectives of power performance and fuel economy, a higher compression ratio is generally better. A higher compression ratio improves power performance and thermal efficiency, leading to corresponding enhancements in vehicle acceleration and maximum speed. However, due to limitations in cylinder material properties and gasoline combustion knock, the compression ratio of gasoline engines cannot be too high.

[SanEdward]

As a frequent driver, let me share my experience with switching to 95-octane fuel. I once drove a high-compression-ratio car that recommended 98-octane in the manual. Trying to save money, I used 95 instead, which resulted in slight engine knocking and a 0.5L/100km increase in fuel consumption. Since that lesson, I've made it a habit to always check the owner's manual before refueling. Most vehicles with compression ratios below 10 can safely use 95 or 92 octane if specified in the manual - like many Japanese cars I've driven that commonly recommend 95. Downgrading fuel grade saves little money and may cause long-term carbon buildup or knocking. During maintenance, technicians always emphasize matching fuel grades to prevent engine component damage. Bottom line: stick with manufacturer recommendations for peace of mind.

[MacMax]

The gasoline grade is essentially a difference in octane rating, with 98 being slightly higher than 95. I've studied car engines, and if the compression ratio is relatively low, say between 8 and 9.5, 95-octane fuel is generally sufficient. However, for high-compression engines, like those with turbochargers, 98-octane fuel is needed to prevent knocking. When changing fuel types, it's best to follow the manual. If the manual states that 92 or 95 can be used, switching to 95 is fine, though fuel consumption might increase slightly. From the data I've seen, insufficient octane can reduce combustion efficiency, slightly raise engine temperature, and potentially worsen emissions. For daily driving, you can try switching to 95 for short city trips to observe the response, but sticking to the original grade long-term is wiser to avoid warranty issues or engine damage. Safe driving comes first—don't risk major problems for minor gains.

[DeMadelyn]

Switching to 95-octane fuel can save money, but it depends on the vehicle's condition. Every time I change fuel, I carefully check the manual for the specified octane rating. Switching from 98 to 95 if it's not compatible can easily cause knocking. The sound is like engine pinging, and severe cases can lead to higher repair costs. High-compression ratio cars are at greater risk, especially during long drives in hot weather. If the manual says it's compatible with 95, then go ahead—fuel consumption may increase slightly, but the savings are minimal. A reminder: fuel quality differences also affect emissions, so regularly checking carbon buildup is more crucial.