What grade of gasoline should a Golf 1.2T use?

[DeConnor]

The Golf 1.2T should use 95-octane gasoline. This fuel grade is recommended in the vehicle's official owner's manual. In addition to checking the owner's manual for the appropriate gasoline grade, you can also find this information on the fuel filler cap, which will typically indicate the recommended fuel. Generally, the fuel 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 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 use of new technologies, the compression ratio alone is no longer the sole determinant of the appropriate fuel grade. High-compression engines can also be tuned to use lower-octane gasoline due to other influencing factors such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the gasoline octane rating, 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 Golf 1.2T occasionally uses the wrong gasoline grade, simply switching back to the correct grade after the tank is empty is sufficient. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles designed for lower-octane fuel, using a higher-octane gasoline will not cause damage, but the increased octane rating can alter the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power and thermal efficiency, with the practical effect being poorer performance. For vehicles designed for higher-octane fuel, using lower-octane gasoline can cause engine knocking. The significantly lower octane rating lowers the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance is created during the upward stroke. This resistance makes the engine run very unevenly. If the knocking is mild, it may only increase noise without significant 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 severe cases.