Should the BYD Han use 95-octane or 92-octane gasoline?
2 Answers
According to the official vehicle manual recommendation, the BYD Han should use 92-octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the BYD Han's fuel filler cap will also indicate the recommended octane rating. 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 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 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 the BYD Han occasionally uses the wrong gasoline grade, simply switch back to the correct octane rating after refueling. 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 value alters 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 designed for higher-octane fuel, using lower-octane gasoline can cause engine knocking. Due to the significantly lower octane value, the reduced ignition point may cause premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance will arise during the upward stroke. This resistance leads to unstable engine operation. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates critical engine conditions, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.
I see many people asking which type of gasoline the BYD Han should use. I think it depends on the model—the pure electric version doesn’t need gasoline at all, but the hybrid version like the DM-i does. BYD officially recommends 92-octane gasoline because its engine is designed to be highly efficient with a relatively low compression ratio, and 92-octane is sufficient to prevent knocking while ensuring smooth and cost-effective daily driving. Although 95-octane is purer and might offer some cleaning benefits, it’s significantly more expensive and not cost-effective unless you frequently drive in high-temperature or high-altitude environments. I’ve been using 92-octane in my hybrid Han for years, and the engine responds quickly and stably, saving me a lot on fuel costs. For beginners, I suggest checking the owner’s manual first to confirm the recommended octane rating—don’t blindly follow the trend of using 95-octane, as it’s wasteful and unnecessary.
