Should the Buick LaCrosse 2.4 use 95 or 92 octane gasoline?
1 Answers
The LaCrosse 2.4 should not use 92 octane gasoline; it requires unleaded gasoline with a nominal octane rating of 93 or higher. The differences between 92 and 95 octane gasoline are as follows: Different compositions: 92 octane gasoline consists of approximately 92% isooctane and 8% n-heptane, while 95 octane gasoline contains about 95% isooctane and 5% n-heptane. Isooctane has better anti-knock properties, whereas n-heptane has poorer anti-knock properties. Therefore, the higher the octane rating, the higher the octane value, indicating better anti-knock performance of the gasoline. Each engine undergoes comprehensive evaluation before leaving the factory, and based on the engine's performance and other data characteristics, the required anti-knock properties are determined, which dictates the appropriate octane rating of gasoline to be used. Different prices: A tank of 95 octane gasoline is slightly more expensive than a tank of 92 octane gasoline. Different power outputs: 95 octane gasoline with a higher octane rating is suitable for engines with higher compression ratios. This is because as the engine speed increases, the ignition timing in the cylinder advances. When the speed reaches a critical point, the air-fuel mixture in the cylinder may ignite prematurely before the spark plug fires, a phenomenon known as "knocking." Increasing the octane rating of the gasoline can effectively enhance the anti-knock performance.
