Should the Mustang use 92 or 95 octane gasoline?
2 Answers
According to the official vehicle manual recommendation, the Mustang should use 95 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the Mustang's fuel cap may also indicate the recommended octane rating. Typically, the required gasoline grade can also be determined based on the engine's compression ratio. Vehicles with a 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 solely determine the required gasoline grade. High-compression engines can also be tuned to use lower-octane gasoline. This is because factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally, the higher the gasoline grade, the higher the octane rating 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 Mustang occasionally uses the wrong gasoline grade, simply switch back to the correct grade after the tank is empty. 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 rating may alter 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 recommended to use higher-octane gasoline, using lower-octane gasoline can cause engine knocking. Due to the significantly lower octane rating, the fuel may ignite prematurely during the compression stroke before the spark plug fires. This premature combustion creates resistance during the upward stroke, causing the engine to run very unstably. Mild knocking may only increase noise without obvious engine damage, but severe knocking indicates serious engine conditions. The vibrations not only affect driving stability but can also cause abnormal wear on pistons and cylinders, and in extreme cases, lead to cylinder scoring.
Regarding the question of whether to use 92 or 95 octane gasoline for the Mustang, as someone who frequently drives a Mustang, I believe the choice depends on the specific requirements of the engine. Performance cars like the Mustang have engines with higher compression ratios. Using lower-octane 92 gasoline can easily cause knocking—that crackling sound inside the engine—which can damage engine components and lead to higher repair costs in the long run. I recommend prioritizing 95 octane or higher gasoline, as it burns more stably under high temperatures, provides more responsive throttle feedback during high-speed driving, and delivers smoother power output. In fact, if you check the user manual, it clearly recommends using gasoline with an octane rating of 91 or above, which corresponds to 95 octane or higher in China. Some people think 92 octane is cheaper and saves money, but the savings on fuel won’t cover even a fraction of engine repair costs. Additionally, if you frequently engage in aggressive driving or track racing, it’s safer to use 98 octane. In short, don’t cut corners—protecting your beloved car is what matters most.
