What grade of gasoline should be used for the Audi Q8?

[LaJourney]

Audi Q8 should use 95-octane gasoline. This gasoline grade is recommended in the vehicle's official user manual. In addition to checking the appropriate gasoline grade in the user manual, you can also find it on the fuel tank cap, which will be clearly marked. Generally, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with an engine compression ratio between 8.6-9.9 should use 92-octane gasoline, those between 10.0-11.5 should use 95-octane gasoline, and those with a higher compression ratio should use 98-octane gasoline. However, with the application of new technologies, the compression ratio alone cannot determine the appropriate gasoline grade, as high-compression engines can also be tuned to use lower-octane gasoline. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, 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 Q8 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: Using a higher-octane gasoline in a vehicle designed for a lower grade will not cause damage, but the increased octane number may alter the fuel's ignition point, leading to delayed combustion in the engine. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. Using a lower-octane gasoline in a vehicle designed for a higher grade can cause engine knocking. The significantly lower octane number lowers the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance will develop during the upward stroke. This resistance makes the engine run very unstably. Mild knocking only increases noise without significant engine damage, but noticeable knocking indicates severe engine conditions, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.