Can 98 Octane and 95 Octane Gasoline Be Mixed?

[DelEmilio]

98 octane and 95 octane gasoline cannot be mixed for use. The hazards of mixing include: affecting the normal operation of the engine, leading to increased car noise, reduced driving power, and potential engine damage. Gasoline is a volatile, flammable liquid hydrocarbon mixture obtained from the distillation, cracking, or pyrolysis of petroleum, used as fuel. Gasoline is classified into different grades based on octane ratings, such as 89, 90, 92, 93, 95, 97, and 98. Characteristics of gasoline: 1. Volatility: In the engine cylinder, it quickly vaporizes and forms a uniform combustible mixture with air. 2. Stability: The ability to resist oxidation under normal temperature and liquid phase conditions is called stability. 3. Anti-knock property: Refers to the gasoline's ability to resist detonation combustion under various usage conditions. 4. Corrosiveness: Sulfur compounds in gasoline can cause corrosion to materials.

[Kathy]

Over the past decade of driving, I've experienced several instances of mixing 98 and 95 octane gasoline. When the gas station ran out of 98 octane, I had to fill my high-compression ratio engine car with 95 octane. After starting the engine, the noise increased noticeably, accompanied by slight vibrations, which felt abnormal. Consulting a car-savvy friend, he explained that the octane rating determines anti-knock capability—98 octane is higher than 95, and mixing them reduces the average anti-knock performance, leading to engine knocking. Prolonged use could damage engine components. Mixed fuel may also increase fuel consumption, wasting money instead. In emergencies, mixing a small amount is acceptable due to residual fuel in the lines, but habitual mixing is strongly discouraged. The manufacturer's specified fuel grade is optimized for engine design, ensuring smooth power delivery and safe driving. Following the manual is key to maintaining vehicle health.

[PresleyDella]

I have a daily commuter car that requires 95-octane gasoline as per the manufacturer's recommendation. One day, the gas station only had 98-octane, so I mixed them once, and the car ran with stable power without major issues. However, a mechanic later told me that mixing gasoline with different octane ratings can cause confusion: 98-octane has stronger anti-knock properties, while 95-octane is weaker. Mixing them may increase the risk of engine knocking, especially during acceleration when the engine is under stress. An occasional mix isn’t a big problem because the car’s computer can adaptively adjust the ignition timing, but frequent mixing can lead to accumulated issues, such as sensor failures or increased fuel consumption. From a cost perspective, 98-octane is significantly more expensive, so mixing doesn’t save money but rather adds extra costs. For safety reasons, next time I’ll wait until the correct fuel grade is available to avoid unnecessary risks to the engine.

[PaisleeDella]

As a cost-conscious car owner, I'd like to discuss the economic impact of mixing fuel grades. 98-octane gasoline is typically more expensive than 95-octane. If your vehicle requires 95-octane, mixing in 98-octane means wasting money. Conversely, mixing 95-octane fuel into a higher-grade requirement lowers the octane rating, potentially causing engine knocking and increased fuel consumption - ultimately costing more. The average octane from mixed fuels won't achieve perfect balance, forcing the engine to adapt with reduced efficiency. In the long run, following the manufacturer's recommended fuel grade saves the most - maintaining performance while avoiding repair costs, ensuring both savings and peace of mind.