What type of fuel should be used for the BJ40?
2 Answers
According to the official vehicle manual recommendations, the BJ40 2022 2.3T Automatic 4WD Excellence Edition should use 95-octane gasoline, while the 2022 2.0T Automatic 4WD Ring Tower Champion Edition and Official Edition should use 92-octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the BJ40's fuel cap also indicates the recommended gasoline type. Typically, the fuel 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 required gasoline grade. High-compression engines can also be tuned to use lower-octane fuel, as other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, higher-octane gasoline has a higher octane number and better anti-knock properties. 92-octane gasoline contains 92% isooctane and 8% n-heptane, while 95-octane gasoline contains 95% isooctane and 5% n-heptane. If the BJ40 occasionally uses the wrong gasoline grade, simply switching back to the correct grade after consumption is sufficient. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles designed for lower-octane fuel, using higher-octane gasoline will not cause damage, but the increased octane number can 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 designed for higher-octane fuel, using lower-octane gasoline can cause engine knocking. The significantly lower octane number reduces the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug ignites, resistance is created 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, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring in extreme cases.
My BJ40 has been running for almost three years, and I've always used 92-octane gasoline. It feels quite smooth. Both the fuel cap and the user manual suggest using 92 or 95-octane, and I choose 92 mainly to save money, especially since fuel prices aren't cheap these days. Using lower-quality fuel can easily lead to carbon buildup or engine damage. For city commuting, the power is sufficient, and it performs well on highways too. When off-roading in mountainous areas, I still use 92-octane—the engine sound remains stable, and it's very durable. Remember not to use 98-octane or anything like that; it's a waste of money with little performance improvement. Also, beware of counterfeit gas stations—stick to big brands like Sinopec or PetroChina for safety. When changing the engine oil, make sure to use the right grade and avoid mixing them up. This way, your car will last longer with fewer repairs.
