Should the 2013 Reiz use 92 or 95 octane gasoline?
4 Answers
According to the official car manual recommendation, the 2013 Reiz should use 92 octane gasoline. For the 2013 Reiz, besides checking the suitable gasoline grade in the car manual, you can also find it on the fuel tank cap, which will also indicate the recommended grade. Generally, the gasoline grade can also be determined based on the engine's compression ratio. 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. However, with the application of some new technologies, the gasoline grade cannot be solely determined by the compression ratio. A high compression ratio can also be adjusted to use lower-grade gasoline because, besides the compression ratio, 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 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 the 2013 Reiz occasionally uses the wrong gasoline grade, simply switch back to the correct grade after use. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower-grade gasoline, using higher-grade gasoline will not cause damage, but the increase in octane number will change the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles recommended to use higher-grade gasoline, using lower-grade gasoline can cause engine knocking. Because the octane number is much lower, the lower ignition point of the gasoline will cause it to ignite prematurely during the compression stroke. If the fuel ignites before the spark plug fires during the compression stroke, resistance will occur during the upward stroke. This resistance will make the engine run very unstably. If it's mild knocking, it will only increase noise without significant damage to the engine. However, if there is noticeable knocking, it indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.
I've been driving an old Reiz for several years, and the fuel issue depends on how you look at it. 92-octane gasoline fully meets the Reiz's engine requirements—the manual clearly states it can use 92, and it's significantly cheaper, perfectly adequate for daily commuting. However, over the years, I've noticed that with 95-octane, the engine runs smoother, especially when climbing hills or during sudden acceleration, where power delivery feels more consistent. The fuel cap indicates 91 or above, meaning the manufacturer left room for upgrades. There's really no need to insist on 95, but if you frequently drive on highways or prioritize driving experience, spending a bit more on 95-octane can be worth it. Alternatively, saving on fuel to invest in better engine oil for maintenance is also a smart choice.
The compression ratio of this V6 engine in the Reiz is around 10.5:1, which isn't particularly high. Since the manufacturer allows the use of 92-octane fuel, it indicates the basic design accommodates lower-grade gasoline. However, I always prefer to give my beloved car better fuel, and I've been using 95-octane for almost two years now. I've noticeably felt less engine vibration, especially during cold starts where it's much quieter. Gas station attendants often tell me that 95-octane is more resistant to knocking and reduces carbon buildup. Although I don't have professional equipment to test it, the spark plugs do look cleaner at each maintenance check. It works out to spending an extra hundred or so each month, which I consider as buying insurance for the engine.
When I first bought my 2013 Reiz, I was also torn about which fuel to use. I asked a senior mechanic at the 4S shop, who said 92-octane would work just fine, as many taxis with the same engine have run hundreds of thousands of kilometers on it. After trying 92-octane for half a year, I found it perfectly adequate for city commuting. However, during a long-distance road trip, the engine warning light suddenly flashed when climbing a long slope with the AC on. After filling up with 95-octane at a service area, the issue immediately improved. Now, I generally use 92-octane in the city but switch to 95-octane for highway driving or when the car is fully loaded. Based on the engine's compression ratio, 92-octane is technically sufficient, but under certain conditions, 95-octane does provide extra peace of mind.
