Can I switch back to 92 after using 95 for half a year?
3 Answers
You can switch back to 92 after using 95 for half a year. In terms of n-heptane content: 95 gasoline contains 5% n-heptane; 92 gasoline contains 8% n-heptane. In terms of isooctane content: 95 gasoline contains 95% isooctane; 92 gasoline contains 92% isooctane. In terms of anti-knock performance: Different gasoline grades represent different fuel anti-knock properties. The higher the gasoline grade, the better the anti-knock performance. 95 gasoline has better anti-knock performance than 92 gasoline. Fuel grades: Automotive fuel grades were introduced after the China V standard, where 92 gasoline replaced 93 gasoline, and 95 gasoline replaced 97 gasoline. Regulations: Motor vehicles must use the specified fuel grade, otherwise engine problems may occur.
Having driven for so many years, my friends often ask this question. If you want to switch back to 92 octane after using 95 for half a year, the most important thing is to check your car's manual. If the manufacturer specifies a minimum of 92 octane, then switching back is absolutely fine. When I switched from 95 back to 92, I specifically monitored fuel consumption and power, and there was virtually no difference. However, older cars need attention—if the engine has significant carbon buildup, lower-octane fuel might cause slight knocking, so listen for tapping sounds during acceleration. It's advisable to run the tank nearly empty before switching to let the fuel system adjust to the new octane. From my own experience, running two full tanks after the switch stabilizes everything, provided you refill at reputable gas stations with reliable 92 octane fuel.
Last time during maintenance at the 4S shop, the technician told me that switching from 95 to 92 mainly depends on the engine compression ratio. Cars with a compression ratio below 10 can completely switch, like many Japanese cars that come factory-labeled for 92 octane. However, it's advised not to switch too frequently as the fuel system needs time to readjust. When I previously switched back to 92 in my German car, the fuel consumption increased by 0.5 liters for the first two weeks before returning to normal. A reminder to everyone: always check the octane rating when refueling. I once accidentally filled up with the wrong grade, and the engine warning light came on. With the current significant price difference in fuel, switching to a lower grade can save a lot of money in the long run, but turbocharged cars should consult a professional technician first.
