Should the old Passat Lingyu use 92 or 95 gasoline?
2 Answers
According to the official car manual recommendation, the old Passat Lingyu should use 92 gasoline. In addition to checking the appropriate gasoline grade in the car manual, the old Passat Lingyu can also check it on the fuel tank cap, which will also be marked. Usually, the gasoline grade can also be determined based on the engine's compression ratio. Cars with an engine compression ratio between 8.6-9.9 should choose 92 gasoline, while cars with an engine compression ratio between 10.0-11.5 should choose 95 gasoline. However, with the use of some new technologies, the gasoline grade cannot be determined solely by the compression ratio. High compression ratio engines can also be tuned to use low-grade gasoline because, in addition to the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally speaking, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. 92 gasoline contains 92% isooctane and 8% n-heptane, while 95 gasoline contains 95% isooctane and 5% n-heptane. If the old Passat Lingyu occasionally uses the wrong gasoline grade, it only needs to switch back to the correct gasoline grade after use. However, if the wrong gasoline grade is used for a long time, the following effects may occur: For vehicles recommended to use low-grade gasoline, using high-grade gasoline by mistake will not cause damage, but the increase in octane number will change the fuel's ignition point, causing the engine to experience delayed combustion. This means the engine's working capacity and thermal efficiency will decrease, and the actual feedback experience is reduced power. For vehicles recommended to use high-grade gasoline, using low-grade gasoline will cause engine knocking. Because the octane number is too low, the gasoline's ignition point decreases and it may ignite prematurely during the compression stroke. If the gasoline ignites before the spark plug fires during the compression stroke, resistance will occur during the upward stroke. This resistance will cause the engine to run very unstable. If it is mild knocking, it will only increase noise and cause no obvious damage to the engine. However, if there is obvious knocking, it indicates that the engine's working condition is already very severe. The vibration not only affects driving stability but also causes abnormal wear of the piston and cylinder, and in severe cases, it may even lead to cylinder scoring.
As someone who has driven the older Passat Lingyu, I believe using 95-octane gasoline is the preferred choice. The engine was designed to match high-octane fuel, and 95-octane ensures smooth operation with reduced noise, avoiding issues like knocking. While 92-octane might work occasionally, you'll notice slower starts or slight shaking during acceleration, and long-term use can lead to carbon buildup and higher maintenance costs. My Lingyu has been running for over a decade, and with consistent use of 95-octane, the fuel consumption remains stable at around 8L, with no major issues. Older cars are inherently more fragile, so proper care can extend their lifespan. Fuel quality is also crucial—always choose reputable gas stations for 95-octane. Don't skimp on those few extra dollars, as safety and performance are far more important.
