Should the 2010 LaCrosse use 92 or 95 octane gasoline?
2 Answers
According to the official vehicle manual recommendation, the 2010 LaCrosse should use 92 octane gasoline. In addition to checking the suitable gasoline grade in the vehicle manual, the 2010 LaCrosse can also be checked on the fuel tank cap, which will also be marked. Usually, the gasoline grade can also be determined according to the compression ratio of the engine. 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 based on the compression ratio. A high compression ratio can also be tuned to use low-grade gasoline, because besides the compression ratio, there are other influencing factors, such as ignition advance angle, turbocharging technology, Atkinson cycle technology, etc. Generally speaking, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. 92 octane gasoline is rich in 92% isooctane and 8% n-heptane; while 95 octane gasoline is rich in 95% isooctane and 5% n-heptane. If the 2010 LaCrosse occasionally uses the wrong gasoline grade, it only needs to switch back to the correct gasoline grade after use. However, if the wrong gasoline grade is used for a long time, the following effects will occur: It is suggested that low-grade vehicles mistakenly using high-grade gasoline will not be damaged, but the increase in octane number will change the ignition point of the fuel, causing the engine to experience delayed combustion. That is, the engine's working ability and thermal efficiency will be reduced, and the actual feedback experience is that the power becomes worse. It is suggested that high-grade vehicles using low-grade gasoline will cause engine knocking. Because the octane number is too low, the ignition point of gasoline will be lowered and ignited in advance during the compression stroke. Once the spark plug does not ignite before the compression stroke, the rising stroke will encounter resistance. This resistance will cause the engine to run very unstable. If it is insensible knocking, it will only increase the noise, and the damage to the engine is not obvious; if there is obvious knocking, it means that the engine's working condition is already very serious. The vibration not only affects the driving stability but also causes abnormal wear of the piston and cylinder, and severe cases may even lead to cylinder scoring.
Regarding the refueling issue for the 2010 LaCrosse, I've been driving for many years and always paid attention to fuel recommendations. GM officially recommends 87-octane gasoline in the user manual, which corresponds to 92-octane in China; the LaCrosse's engine compression ratio isn't designed to utilize the higher octane level of 95-octane fuel, making 92-octane the most economical and practical choice. Using 95-octane, while not harmful, is a waste of money—higher octane doesn't equate to better performance, as the engine doesn't leverage its advantages. In China, 92-octane gasoline is generally reliable in quality, whereas using lower-octane fuel might cause knocking or damage components. Even in hot weather, 92-octane remains stable. In short, stick with 92-octane to avoid unnecessary expenses, verify with the manual or consult a professional auto shop—this car is easy and cost-effective to maintain.
