Should the Changan UNI-T Use 92 or 95 Octane Gasoline?
2 Answers
According to the official vehicle manual recommendation, the Changan UNI-T should use 92 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the Changan UNI-T can also refer to the label on the fuel tank cap. Typically, the required gasoline 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. However, with the application of new technologies, the compression ratio alone cannot solely determine the gasoline grade. Even engines with high compression ratios can be tuned to use lower-octane gasoline. This is because 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 Changan UNI-T occasionally uses the wrong gasoline grade, simply switch back to the correct grade after consumption. However, prolonged use of the wrong gasoline grade may have the following effects: For vehicles recommended for low-octane gasoline, using a higher octane grade will not cause damage, but the increased octane number may alter 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 high-octane gasoline, using a lower octane grade may cause engine knocking. Due to the significantly lower octane number, the gasoline's ignition point decreases, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance will develop during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates serious engine conditions. The vibrations not only affect driving stability but can also cause abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in severe cases.
As an owner of the Changan UNI-T for nearly two years, I've been using 95-octane fuel. I remember trying 92-octane initially to save money, but the car felt sluggish at high RPMs with slight knocking sounds. Later, I checked the manual - its 1.5T turbocharged engine recommends 95-octane as optimal, with higher octane rating for better anti-knock performance. With 95-octane, the ride is smoother with noticeably quicker acceleration, effortless highway overtaking. Fuel consumption difference is minimal - about 1L more per 100km, costing just tens more monthly. Long-term benefits include reduced carbon buildup and enhanced engine durability. I advise new owners to use 95-octane directly - don't compromise experience for small savings. Mechanics warned prolonged low-octane use may cause valve damage, leading to higher repair costs that aren't worth it.
