Should Corolla use 92 or 95 octane gasoline?

[StRhett]

Toyota Corolla is suitable for using 92 octane gasoline, and of course, you can also choose 95 octane gasoline, but under normal circumstances, there is not much necessity to use 95 octane gasoline. In addition to checking the suitable gasoline grade in the car manual, you can also check it on the fuel tank cap, which will also be marked. Usually, the gasoline grade can also be determined based on the engine's compression ratio. Cars with an engine compression ratio between 8.6-9.9 should choose 92 octane gasoline, while cars with an engine compression ratio between 10.0-11.5 should choose 95 octane gasoline. However, with the use of some new technologies nowadays, the gasoline grade cannot be determined solely by the compression ratio. A high compression ratio can also be adjusted to use low-grade gasoline. This is because, in addition to the compression ratio, there are other influencing factors, such as the ignition advance angle, turbocharging technology, and Atkinson cycle technology. Generally speaking, the higher the gasoline grade, 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. If Corolla occasionally uses the wrong gasoline grade, you only need to switch back to the correct gasoline grade after using it up. However, if the wrong gasoline grade is used for a long time, it will have the following effects: For vehicles recommended to use low-grade gasoline, using high-grade gasoline by mistake will not cause damage, but the increase in octane number will change the fuel's ignition point, leading to delayed combustion in the engine. That is, the engine's working capacity and thermal efficiency will both decrease, and the actual feedback experience is that the power becomes worse. For vehicles recommended to use high-grade gasoline, using low-grade gasoline will cause engine knocking. Because the octane number is too low, the gasoline's ignition point decreases and it will be ignited prematurely during the compression stroke. Once the gasoline combusts before the spark plug ignites during the compression stroke, resistance will occur during the upward stroke. This resistance will cause the engine to run very unstably. If it is only slight knocking, it will just increase noise and the damage to the engine is not obvious. If there is obvious knocking, it means the engine's working condition is already very severe. The vibration not only affects driving stability but also causes abnormal wear of the piston and cylinder, and in severe cases, it can even lead to cylinder scoring.