Should the Audi Q2 use 92 or 95 octane gasoline?
2 Answers
According to the official vehicle user manual recommendation, the Audi Q2 should use 95 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle user manual, the Audi Q2 can also check the fuel tank cap, which will also be marked. Usually, the gasoline grade can also be determined based on the engine compression ratio. Vehicles with an engine compression ratio between 8.6-9.9 should choose 92 octane gasoline, while those with a compression ratio between 10.0-11.5 should choose 95 octane gasoline. However, with the use of some new technologies, 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, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. 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 the Audi Q2 occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended for low-grade gasoline, using high-grade gasoline will not cause damage, but the increase in octane number will change the fuel's ignition point, leading to delayed combustion in the engine. This means the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles recommended for high-grade gasoline, using low-grade gasoline can cause engine knocking. Because the octane number is too low, the gasoline's ignition point decreases and it may ignite prematurely during the compression stroke. If combustion occurs before the spark plug ignites, resistance will occur during the upward stroke. This resistance will make the engine run very unstably. If the knocking is mild, it may only increase noise without significant engine damage. However, if the knocking is severe, it indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.
I've been driving an Audi Q2 for several years and always use 95-octane gasoline because the manual clearly recommends 95-octane or higher. At first, I thought about trying 92-octane to save some money, but after one attempt, I noticed slight engine knocking during acceleration and reduced power. Later, I learned from research that the Audi Q2's turbocharged engine has a high compression ratio, and lower-octane gasoline can cause premature combustion or abnormal knocking. Using 92-octane long-term may damage pistons or cylinder walls. These issues don't appear immediately but accumulate, leading to much higher repair costs. Although 95-octane fuel is more expensive per liter, it burns more efficiently, resulting in better fuel economy, so the annual cost difference isn't significant. I recommend drivers get into the habit of checking the fuel recommendation label inside the fuel filler flap or confirming it in the owner's manual.
