How much impact does filling a Mercedes-Benz C200 with 92-octane gasoline have?

[Toby]

According to the official vehicle manual recommendation, the Mercedes-Benz C200 should use 95-octane gasoline. Filling it with 92-octane gasoline will have an impact. If the Mercedes-Benz C200 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 lead to the following effects: For vehicles recommended to use lower-octane gasoline, mistakenly using higher-octane gasoline will not cause damage, but the increase in octane rating will alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in a noticeable decline in performance. For vehicles recommended to use higher-octane gasoline, using lower-octane gasoline can cause engine knocking. Due to the significantly lower octane rating, the reduced ignition point may cause premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance will arise during the upward stroke. This resistance makes the engine run very unevenly. If the knocking is imperceptible, it may only increase noise without obvious engine damage. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in extreme cases. In addition to checking the recommended gasoline grade in the vehicle manual, the Mercedes-Benz C200's fuel cap also indicates the appropriate octane rating. Generally, the gasoline grade can also be determined by the engine's compression ratio. Vehicles with a compression ratio between 8.6-9.9 should use 92-octane gasoline, while those with a ratio between 10.0-11.5 should use 95-octane gasoline. However, with advancements in technology, the compression ratio alone cannot solely determine the required gasoline grade. High-compression engines can be tuned to use lower-octane gasoline due to other influencing factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, higher gasoline grades have higher octane ratings and better anti-knock properties. 92-octane gasoline contains 92% isooctane and 8% n-heptane, while 95-octane gasoline contains 95% isooctane and 5% n-heptane.