Should the Mercedes-Benz A-Class use 92 or 95 octane gasoline?
2 Answers
The Mercedes-Benz A-Class is recommended to use 95 octane gasoline because it has higher purity compared to 92 octane gasoline, and lower purity gasoline can harm the engine. Gasoline grades: Both 92 and 95 are gasoline grades, representing the anti-knock performance. A higher grade indicates better anti-knock capability, but it does not relate to the quality of the gasoline itself. It does not mean that higher-grade gasoline has fewer impurities. Basis for gasoline selection: The type of gasoline a car uses depends on the matching with the engine system, essentially related to the engine's compression ratio. A higher compression ratio results in greater power and efficiency but poorer stability, thus requiring gasoline with higher anti-knock properties. If the compression ratio does not meet the requirement, using a higher gasoline grade will not significantly enhance performance. At most, it may slightly improve cleanliness and lower carbon emissions, but the effect is not very noticeable.
Last time I drove my friend's Mercedes-Benz A200L, I specifically looked up the information. The official recommendation states that it can use 92 octane fuel but strongly suggests 95. Actually, turbocharged engines have high compression ratios, and 92 octane fuel's anti-knock performance isn't sufficient. Over time, it can cause the ECU to frequently adjust the ignition timing, leading to increased fuel consumption instead of savings. I tried comparing two tanks of 92 octane fuel and clearly felt weaker acceleration during stop-and-go city driving, along with more engine noise. Although 95 octane fuel is more expensive now, it allows for more complete combustion in the cylinders and reduces carbon buildup. The cost difference per kilometer is less than 0.2 yuan, so it's really not worth saving at the expense of the engine. If you frequently drive on highways, I recommend using 98 octane fuel directly—the acceleration feel is completely different.
