What grade of gasoline should the Odyssey use?
2 Answers
The Odyssey should use 92-octane gasoline, as this is the grade recommended in the vehicle's official user manual. In addition to checking the appropriate gasoline grade in the user manual, you can also find it on the fuel tank cap, which will be clearly marked. Typically, 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. If the compression ratio is even higher, 98-octane gasoline is recommended. However, with the use of new technologies, the compression ratio alone cannot determine the appropriate gasoline grade, as high-compression engines can also be tuned to use lower-octane gasoline. Other 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 Odyssey occasionally uses the wrong gasoline grade, simply switching back to the correct grade after use is sufficient. However, prolonged use of the wrong gasoline grade can have the following effects: For vehicles designed for lower-octane gasoline, using a higher grade will not cause damage, but the increased octane rating can 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 gasoline, using a lower grade can cause engine knocking. The significantly lower octane rating lowers the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance is created during the upward stroke. This resistance makes the engine run very unevenly. Mild knocking may only increase noise without obvious engine damage, but severe knocking indicates serious engine issues, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, potentially leading to severe damage like cylinder scoring.
As a veteran Odyssey driver with eight years of experience, I'm very familiar with this issue. My 2015 Odyssey has always used 92-octane fuel, as clearly stated in the manual and on the fuel cap. In fact, 92 is perfectly sufficient - the engine's compression ratio is 11.1, making 95 completely unnecessary. However, during a self-drive trip to the northwest when I couldn't find 92, I temporarily used 95 without problems, but avoid mixing them long-term. Remember that fuel quality matters more than the octane rating - don't be tempted by cheap gas at small stations, as impurities can clog fuel injectors. One repair could cost you three years' worth of 95-octane fuel!
