Does It Have Any Impact If a Car Designed for 92 Octane Uses 95 Octane?
2 Answers
Using 95 octane in a car designed for 92 octane does have an impact. If you accidentally use the wrong gasoline grade occasionally, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade can lead to the following effects: For vehicles designed for lower octane, using higher octane gasoline will not cause damage, but the increased octane rating alters the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power output and thermal efficiency, with the actual experience being poorer performance. For vehicles designed for higher octane, using lower octane gasoline can cause engine knocking. Due to the significantly lower octane rating, the gasoline's ignition point decreases, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires during the compression stroke, resistance is created during the upward stroke. This resistance makes the engine run very unstably. If the knocking is mild, it may only increase noise without significant engine damage. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in severe cases. Besides checking the recommended gasoline grade in the car's manual, you can also find it on the fuel tank cap. Typically, the gasoline grade can also be determined based on the engine's compression ratio. Cars with a compression ratio between 8.6-9.9 should use 92 octane, while those with a compression ratio between 10.0-11.5 should use 95 octane. However, with the application of new technologies, the compression ratio alone cannot determine the appropriate gasoline grade. High compression ratio engines can be tuned to use lower octane gasoline due to other influencing factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the gasoline octane rating, the higher the octane number and the better the anti-knock performance. 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline contains 95% isooctane and 5% n-heptane.
I've been driving for many years and often encounter issues with gasoline octane ratings. My car originally used 92-octane fuel, but once when the gas station only had 95-octane available, I tried filling up with it. After driving for a few days, I noticed the engine ran normally without any unusual noises or vibrations. This is actually a good thing because 95-octane fuel has a higher octane rating and better anti-knock performance, which protects the engine, especially during high-speed driving. However, if you use fuel with a lower octane rating than 92, such as 90-octane, there might be a risk of engine knocking, which could damage the engine. Overall, accidentally using higher-octane fuel doesn't have much impact—it just costs more, but performance won't suffer, and it won't harm the car. Still, I'll stick to the manual-recommended 92-octane fuel in the future, as it saves money and hassle while also extending engine life. After driving for so long, this is just a minor issue—just something to be mindful of.
