Is it mandatory to use 95-octane gasoline for the Bora 1.4T?

[VonEverett]

According to the official vehicle manual recommendation, the Bora 1.4T should use 95-octane gasoline. If the Bora 1.4T occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, long-term use of the wrong gasoline grade may have 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 poorer performance as experienced by the driver. 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 develop during the upward stroke. This resistance makes the engine run very unstably. Mild knocking only increases noise without obvious engine damage, but 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 severe cases. Besides checking the vehicle manual for the appropriate gasoline grade, the Bora 1.4T's fuel cap also displays this information. 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 between 10.0-11.5 should use 95-octane gasoline. However, with modern technologies, the compression ratio alone cannot determine the required gasoline grade. High compression ratio 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.