Changan CS55 Plus: Should I Use 92 or 95 Octane Gasoline?
4 Answers
According to the official vehicle manual recommendation, the Changan CS55 Plus should use 92 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, you can also find it indicated on the fuel tank cap of the Changan CS55 Plus. Generally, 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 gasoline grade cannot be solely determined by the compression ratio. A high compression ratio can also be tuned to use lower octane gasoline because, apart from the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, the higher the gasoline octane number, the higher the octane value 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 you occasionally use the wrong gasoline grade in the Changan CS55 Plus, simply switch back to the correct grade after consumption. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower octane gasoline, using higher octane gasoline will not cause damage, but the increase in octane value can alter the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. Due to the significantly lower octane value, the gasoline's ignition point decreases, causing premature ignition during the compression stroke. If combustion occurs before the spark plug ignites, resistance will develop during the upward stroke. This resistance makes the engine run very unstably. 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, and in severe cases, cylinder scoring.
I remember driving for many years and pondering engine designs. SUVs like the Changan CS55 Plus usually have a low engine compression ratio, and the manufacturer's manual recommends 92-octane gasoline as the most cost-effective option. The 92-octane rating is sufficient for daily driving, such as city commuting or short trips, with a very low risk of engine knocking, and it saves money on fuel. Using 95-octane, while it has a higher octane rating and better anti-knock properties, might make acceleration slightly smoother, but the difference is so minimal it's almost imperceptible, and spending a few hundred extra bucks each month isn't worth it. It won't harm the engine, but the long-term cost-performance ratio is low. I suggest checking the manual to confirm and not needlessly switching octane ratings—92-octane is widely available at gas stations, making it much more convenient. If you're genuinely curious about performance differences, you can try comparing, but I think most people find sticking with 92-octane is enough—safe and worry-free.
As a salaried worker, I've been using 92-octane gasoline in my CS55 Plus for several years purely to save money. 92-octane is a few cents cheaper per liter than 95-octane, saving me about a thousand yuan a year, which I can use for maintenance or more fuel. The manufacturer states that 92-octane is the standard, with moderate combustion efficiency and compliant emissions. While 95-octane seems slightly more environmentally friendly, its actual contribution is negligible. For daily driving like school runs or shopping, the engine runs smoothly without any issues. Higher octane might slightly boost performance, but the CS55 Plus engine isn't sensitive to it, making the extra cost unjustified. If the tank is nearly empty and 92-octane isn't available, using 95-octane in an emergency is fine. Long-term mixed use might cause carbon buildup, but it's easily manageable. In short, prioritizing economy with 92-octane is wise—the manual is clear, so don't follow others in splurging on more expensive fuel.
As a newbie car buyer, I was also confused at first. After checking the Changan CS55 Plus user manual, which recommends 92-octane gasoline, I've been using it without any issues. 92-octane is sufficient—the engine is designed to match it, making it worry-free and cost-effective. 95-octane is significantly more expensive with minimal differences that are hardly noticeable. Don't worry about using the wrong octane damaging your car; the engine is durable, and the knock sensor will alert you if there's an issue. Simply put, just choose 92-octane at the gas station—the manual is the authoritative reference. By the way, always check the fuel grade label when refueling to avoid mixing them up. With these basics covered, you can drive with peace of mind.
