Should the Volkswagen Tacqua use 92 or 95 octane gasoline?
2 Answers
According to the official vehicle manual recommendations, most models of the Tacqua should use 92 octane gasoline, while the Tacqua-2021-280TSI-DSG-Yue Pro Smart Connect Edition and R-Line Smart Connect Edition should use 95 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the Tacqua's fuel tank cap also indicates the recommended octane rating. Typically, 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 use 95 octane gasoline. However, with the application of new technologies, the compression ratio alone cannot determine the gasoline grade, as high-compression engines can also be tuned to use lower-octane fuel. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. 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 Tacqua 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 to use lower-octane gasoline, using higher-octane fuel will not cause damage, but the increased octane number may alter the fuel's ignition point, leading to delayed combustion in the engine. This reduces the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles recommended to use higher-octane gasoline, using lower-octane fuel can cause engine knocking. The significantly lower octane number reduces the gasoline's ignition point, causing premature ignition during the compression stroke. If the fuel ignites before the spark plug fires, resistance occurs during the upward stroke. This resistance makes the engine run very unstably. Mild knocking only increases noise without obvious engine damage, but severe knocking indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.
I think the Volkswagen Tacqua is more suitable for using 95-octane gasoline because the engine has a high design compression ratio. The lower octane rating of 92-octane fuel can easily cause knocking, and that engine vibration can be uncomfortable. Over time, the engine may wear out faster, and fuel consumption could also increase. When I drove this car before, I tried using 92-octane, and it felt sluggish when stepping on the accelerator, especially during highway acceleration—it was noticeably delayed. Later, after switching to 95-octane, the performance became much smoother, with quicker power response and quieter operation. Of course, 95-octane is a bit more expensive, costing an extra few dozen yuan per month, but in the long run, it saves on repair costs and is more economical. Also, remember to choose reliable gas stations for fuel quality—don’t skimp and use low-quality gasoline. During regular maintenance, ask the mechanic to check the spark plug condition. This way, the car will run more steadily and safely.
