Can a Car Designed for 92 Octane Use 95 Octane Fuel?
2 Answers
A car designed for 92 octane gasoline can use 95 octane fuel, but it is not recommended. It is best to use the fuel grade specified for the vehicle. Reference for gasoline grade selection: The main difference between different gasoline grades lies in their anti-knock performance, which is an important indicator for evaluating fuel quality. Cars 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. If the compression ratio is even higher, 98 octane gasoline should be used. Generally, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. Effects of long-term use of incorrect gasoline grade: Using a higher octane fuel in a car designed for a lower octane will not cause damage, but the increase in 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. Conversely, using a lower octane fuel in a car designed for a higher octane can cause engine knocking. The upward stroke may encounter resistance, leading to abnormal wear of pistons and cylinders, and in severe cases, even cylinder scoring.
As a veteran driver with twenty years of experience, I've seen many similar cases. A car designed for 92-octane fuel can absolutely run on 95-octane gasoline without harming the engine. Higher-octane fuel is primarily engineered for anti-knock properties—95-octane has a higher octane rating, but since engines tuned for 92-octane have compression ratios matched to that grade, using 95-octane won’t noticeably prevent knocking, boost power, or improve fuel economy. Some mistakenly believe premium fuel cleans the engine better, but that’s purely a myth—all gasoline contains basic detergents with similar effectiveness. If you temporarily can’t find 92-octane, substituting with 95 is fine. However, long-term use just means spending extra, perhaps ¥100-200 more per month, which is entirely unnecessary. Stick to your car manual’s recommendation: 92-octane is the optimal choice—safe, economical, and freeing up cash for maintenance.
