What grade of gasoline should the Sagitar 1.4T use?

[WilliamFitz]

1.4T Sagitar should use 95-octane gasoline, as this fuel grade is recommended in the vehicle's official user manual. In addition to checking the appropriate gasoline grade in the user manual, the 1.4T Sagitar's fuel cap also indicates the recommended grade. Generally, the fuel grade can also be determined based on the engine's compression ratio. Vehicles with a compression ratio between 8.6-9.9 should use 92-octane gasoline, while those with a compression ratio between 10.0-11.5 should use 95-octane gasoline. If the compression ratio is higher, 98-octane gasoline is recommended. However, with the application of new technologies, the compression ratio alone cannot determine the fuel 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 1.4T Sagitar 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: Using a higher-octane gasoline in a vehicle designed for lower-octane fuel will not cause damage, but the increased octane number can alter the fuel's ignition point, leading to delayed combustion. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. Using a lower-octane gasoline in a vehicle designed for higher-octane fuel can cause engine knocking. Due to the significantly lower octane number, the gasoline may ignite prematurely during the compression stroke before the spark plug fires. This premature ignition creates resistance during the upward stroke, causing unstable engine operation. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates serious engine issues, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.