Is It Necessary to Run Empty When Switching from 92 to 95 Octane?
3 Answers
It is recommended to completely use up the 92 octane gasoline before refueling with 95 octane gasoline, as this helps extend the engine's service life. Below are some additional details: Hazards of mixing different octane ratings: 92 octane and 95 octane gasoline have different stability levels. If they are extensively mixed, the stability of the gasoline may be compromised. When driving with mixed gasoline, the engine may experience knocking or detonation, and vehicle vibration will noticeably increase, potentially causing damage to the engine and leading to malfunctions. Important notes: When refueling, follow the instructions on the fuel tank cap. Of course, you can also choose to switch to a higher octane rating. However, higher octane gasoline does not necessarily result in better performance or provide additional protection for the engine. If the vehicle requires 95 octane gasoline, never use 92 octane; if it requires 92 octane, you may use 95 octane. Avoid frequently switching between different octane ratings, as this may affect the vehicle's fuel consumption.
As a seasoned driver who frequently researches fuel, I can tell you straight away that there's no need to run the tank empty before switching to 95 octane. Mixing 92 and 95 is completely fine—the engine's adaptive adjustment will complete the transition within 200 kilometers. The most cost-effective approach is to fill up with 95 when the tank is at a quarter full. After a full tank and driving about 500 kilometers, the fuel transition is basically complete. You'll notice a clearer difference by checking the average fuel consumption displayed on the dashboard. Initially, mixed fuel consumption may increase by 0.3–0.5 liters, but once the combustion chamber and catalytic converter adapt, it actually becomes more fuel-efficient. I tested this before—half a tank of 92 mixed with 95 actually made the power response smoother. However, avoid using fuel additives during the mixed-fuel tank, as they can interfere with the ECU's learning of fuel correction values.
Experience from changing oil more than ten times: Switching from 92 to 95 octane doesn't require emptying the tank at a gas station. Modern engine ECUs are smart enough—the oxygen sensor will adjust the ignition timing in real-time when burning mixed fuel. Just drive normally, and you'll notice a clear power boost after 200-300 km of mixed-fuel driving. I always keep an emergency fuel can in my car. Once, after the fuel light came on, I added 3 liters of 92 octane as an emergency measure, then topped up with 40 liters of 95—no issues while driving. However, for older fuel-injection cars, be cautious as mixed fuel might trigger fault codes. Pay special attention to cold starts; if idle shakes noticeably with mixed fuel, warm up the car for five minutes.
