Will Using 95 Octane Gasoline Damage the Mazda 3 Axela?
2 Answers
According to the official vehicle manual recommendation, the Mazda 3 Axela should use 92 octane gasoline. In addition to checking the suitable gasoline grade in the vehicle manual, the Mazda 3 Axela's fuel cap also indicates the recommended octane rating. Generally, the gasoline 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 appropriate gasoline grade. Engines with high compression ratios can still be tuned to use lower octane gasoline due to other influencing factors such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the gasoline octane rating, the higher the octane number 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. Occasionally using the wrong gasoline grade in the Mazda 3 Axela only requires switching back to the correct grade after consumption. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower octane gasoline, using higher octane gasoline will not cause damage, but the increased octane number may alter the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power and thermal efficiency, with the actual experience being poorer performance. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. Due to the significantly lower octane number, the fuel's ignition point decreases, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance will arise during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without significant engine damage, but noticeable knocking indicates severe engine conditions. The vibrations not only affect driving stability but can also cause abnormal wear on the pistons and cylinders, potentially leading to severe engine damage like cylinder scoring.
I drove a Mazda3 (Axela) for several years and also tried using 95-octane gasoline. I didn't feel any harm to the car at all. The engine still ran smoothly, and the startup response was even a bit quicker. Modern cars are equipped with ECU systems that automatically adjust ignition timing. Higher-octane fuel is less prone to knocking, so it won't damage internal components. However, the Mazda3 manual specifies 92-octane fuel, which means using 95-octane is actually a waste of money with no additional benefits. I later switched back to 92-octane, and the savings were enough for minor maintenance. The difference in gasoline is just a cost issue—don't worry unnecessarily about engine damage. Regularly changing the air filter is more critical to ensure fuel efficiency. In short, don't be afraid to use 95-octane in your Mazda3; it's smart enough to handle various fuel types. Instead of spending extra on gasoline, it's better to invest in higher-quality engine oil.
