Which is more fuel-efficient for the same car, using 95 or 92 octane gasoline?

[RebeccaLynn]

The same car using 95 octane gasoline is more fuel-efficient than using 92 octane gasoline, primarily because higher-octane gasoline has a higher calorific value. Higher octane means higher calorific value: The density of 92 octane gasoline is approximately 0.72 kg/L, while the density of 95 octane gasoline is about 0.725 kg/L. Higher-octane gasoline has a greater density, meaning that for the same volume, higher-octane gasoline contains more combustible material, resulting in a higher calorific value and more heat released upon combustion. Therefore, for the same volume, higher-octane gasoline delivers better performance. Fuel consumption differences vary across different car models: The difference in fuel consumption is more noticeable in models that are more sensitive to fuel adaptability. For example, many European and American models are highly sensitive to fuel quality, showing significant differences in both power and fuel economy when using 92 octane versus 95 octane gasoline. This is also one of the reasons why many small-displacement turbocharged engines in European and American cars require the use of 95 octane gasoline.

[DiAliyah]

I've driven the same car before and tried both 92 and 95 octane gasoline. I feel that 95 octane might be slightly more fuel-efficient. The manual recommends 92 octane for my car, but 95 octane has a higher octane rating and burns more completely. When driving continuously on highways, using 95 octane clearly results in lower fuel consumption, saving about 0.3 to 0.5 liters per 100 kilometers. However, in city stop-and-go traffic, there's no noticeable difference. Ultimately, it depends on the car's design and driving habits. If you frequently drive long distances, 95 octane can show its advantages; but for daily use, 92 octane is sufficient because 95 octane is more expensive, and overall it might not be cost-effective. I suggest testing it with your odometer first to avoid wasting money. In short, following the manufacturer's recommendation won't let you down—don't overcomplicate things.

[DeAdaline]

As a car enthusiast, I've researched this issue extensively. 95-octane gasoline has a higher octane rating and better anti-knock properties, allowing for more stable engine combustion, especially during acceleration or uphill driving where fuel consumption may be slightly lower. However, for regular cars with lower compression ratios, 92-octane is perfectly adequate. Take my car for example - the engine was originally designed for 92-octane. When using 95-octane, the fuel pump temperature decreases slightly with less than 2% reduction in fuel consumption, but the price is 10% higher, making it less economical than 92-octane. For track racing or high-speed driving, 95-octane might be more fuel-efficient; but for daily commuting, it's not worth overthinking. Remember: Efficient driving habits like gentle acceleration and maintaining steady speed matter more than fuel grade. You'll know what works best through experience.

[OKyle]

I always think about saving money, so I compared using 92 and 95 octane fuel in the same car. After several tests, I found that 95 octane consumes about 0.4 liters less per 100 kilometers on long trips, but the price per liter is a few cents higher, so the total cost is about the same. The manufacturer says 92 octane is fine, so I don’t bother switching. Occasionally using 95 octane feels smoother in terms of power, but that might just be psychological. The key is not to mix or randomly switch fuel grades, as it can cause deposits in the fuel system and increase consumption. For beginners, just follow the manual—don’t experiment with fuel-saving tricks. A simple life is the easiest.