Is 95 Octane Gasoline Mandatory for the Lavida 1.4T?

[DiEvelyn]

According to the official vehicle manual recommendation, the Lavida 1.4T should use 95 octane gasoline. In addition to checking the suitable gasoline grade in the vehicle manual, the Lavida 1.4T's fuel cap also indicates the recommended octane rating. 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, while those with a compression ratio between 10.0-11.5 should opt for 95 octane gasoline. However, with the application of new technologies, the compression ratio alone cannot solely determine the gasoline grade. High compression ratio engines can be tuned to use lower octane gasoline because factors beyond compression ratio, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, higher octane gasoline has a higher octane number and better anti-knock properties. 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline consists of 95% isooctane and 5% n-heptane. If the Lavida 1.4T occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles recommended for lower octane gasoline, using higher octane gasoline will not cause damage, but the increased octane number alters the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power and thermal efficiency, manifesting as poorer performance. For vehicles recommended for higher octane gasoline, using lower octane gasoline can cause engine knocking. The significantly lower octane number reduces the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance is generated during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without significant engine damage, but noticeable knocking indicates severe engine conditions. The vibrations not only affect driving stability but also cause abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in severe cases.