What are the effects of using 95 octane fuel in a car designed for 92 octane?
2 Answers
A car designed for 92 octane fuel can use 95 octane gasoline. 95 octane gasoline is purer than 92 octane and releases more kinetic energy when burned in the engine. As a result, the higher fuel efficiency will become more apparent in terms of the power provided by the fuel. Reference for gasoline grade selection: The main difference between different gasoline grades lies in their anti-knock performance, which is an important indicator for measuring fuel quality. Cars with an engine compression ratio between 8.6-9.9 should use 92 octane gasoline, while those with a compression ratio between 10.0-11.5 should use 95 octane gasoline. If the compression ratio is even higher, 98 octane gasoline should be selected. Generally, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. Long-term effects of using the wrong gasoline grade: Using a higher octane fuel in a car designed for a lower octane will not cause damage, but the increase in octane number can alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease. Conversely, using a lower octane fuel in a car designed for a higher octane can cause engine knocking, increased resistance during the upward stroke, and abnormal wear on the piston and cylinder. In severe cases, it can even lead to cylinder scoring.
I know this too well! My old Toyota ran on 92-octane for seven years, and once a gas station attendant accidentally filled it with 95-octane. It did feel a bit more responsive on the throttle, and the engine noise was slightly muffled. Mechanic Lao Wang said higher-octane fuel has better anti-knock properties, but our car's compression ratio isn't high enough, leading to incomplete combustion and potential carbon buildup over time. The biggest issue is the hit to the wallet—95-octane costs 0.8 yuan more per liter, adding 40 yuan per tank, with no actual fuel efficiency improvement. Using it occasionally in emergencies is fine, but don’t fall for sales pitches about power boosts—it’s purely psychological. Stick to the manufacturer’s recommended octane for the most cost-effective performance.
