8th Generation Accord: Should I Use 92 or 95 Octane Gasoline?

[SanTeagan]

The 8th generation Accord can use 92 octane gasoline. This octane rating is officially recommended in the vehicle's user manual. In addition to checking the appropriate gasoline octane in the user manual, the recommended octane rating is also indicated on the fuel tank cap. You can usually determine the suitable gasoline grade 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. If the compression ratio is even higher, 98 octane gasoline is recommended. However, with the application of new technologies, the compression ratio alone cannot determine the required gasoline grade. Engines with high compression ratios can also be tuned to use lower-octane gasoline due to 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. If you occasionally use the wrong gasoline octane in the 8th generation Accord, simply switch back to the correct octane after consumption. However, prolonged use of the wrong octane may have the following effects: For vehicles designed for lower octane, 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 reduces the engine's power output and thermal efficiency, resulting in poorer performance. For vehicles designed for higher octane, using lower-octane gasoline may cause engine knocking. Since the octane number is significantly lower, the fuel may ignite prematurely during the compression stroke before the spark plug fires. This premature ignition creates resistance during the upward stroke, causing unstable engine operation. Mild knocking may only increase noise without noticeable engine damage, but severe knocking indicates serious engine issues, affecting driving stability and causing abnormal wear on pistons and cylinders, potentially leading to cylinder scoring.