Should the Roewe RX5 use 92 or 95 octane gasoline?

[LeonardoAnn]

According to the official vehicle manual recommendation, the Roewe RX5 should use 92 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle 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. However, with the application of new technologies, the compression ratio alone cannot determine the gasoline grade. A high compression ratio can still be tuned to use lower octane 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 octane number, the higher the octane value 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 Roewe RX5 occasionally uses the wrong gasoline grade, simply switch 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 increase in octane value will alter the fuel's ignition point, leading to delayed combustion in the engine. This means the engine's power output and thermal efficiency will decrease, resulting in poorer performance. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. Because the octane value is too low, the lowered ignition point may cause premature ignition during the compression stroke. If combustion occurs before the spark plug ignites, resistance will arise during the upward stroke. This resistance makes the engine run very unstably. If the knocking is imperceptible, it may only increase noise without significant engine damage. However, noticeable knocking indicates severe engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in severe cases, cylinder scoring.

[McCourtney]

I've been driving the Roewe RX5 for several years, always using 92-octane gasoline, and it feels quite smooth with no abnormal engine noises. Generally speaking, the RX5 is designed for 92-octane fuel due to its relatively low compression ratio, so there's no need to upgrade to 95-octane. While 95-octane has a higher octane rating and better anti-knock performance, it offers negligible improvements for regular driving, and fuel consumption doesn't change noticeably. I've checked the manual and the fuel cap label, which clearly state that 92-octane is the manufacturer's recommendation—it saves money and hassle. Using the wrong octane might lead to carbon buildup or sluggish acceleration, but the RX5's adaptive system can adjust, so it's not a big issue. If you frequently drive on mountain roads or carry heavy loads, occasionally using 95-octane is fine, but for city commuting, 92-octane is perfectly stable. Bottom line: check your car's manual and don't waste money worrying unnecessarily.

[StJulian]

As a young person, I choose gasoline considering cost savings and environmental protection. My Roewe RX5 uses 92-octane fuel, which is dozens of yuan cheaper per tank than 95-octane, with similar fuel consumption and slightly reduced carbon emissions. 95-octane fuel is purer and may provide smoother acceleration, but the RX5's engine isn't picky—92-octane works perfectly. From an environmental perspective, 92-octane requires simpler refining and consumes fewer resources. If you're after a more exhilarating drive, you could try 95-octane, but the extra cost might be better spent on other maintenance. The manual generally recommends 92-octane, so base your choice on budget and habits—don't waste money by following hearsay.

[Rick]

I've worked in car repair for many years, and most models of the Roewe RX5 recommend 92-octane gasoline. The gasoline grade depends on the engine compression ratio, and the RX5's isn't particularly high, so 92 is sufficient to prevent knocking. Only some turbocharged versions suggest 95-octane. The key is not to mix different grades to avoid carbon buildup in the fuel system or engine shaking. The fuel cap or manual provides clear instructions—don't guess. Simply put: 92 is safe and cost-effective, while 95 is unnecessary unless the owner's manual specifically states otherwise. Just ensure consistent fuel quality, as modern cars can adapt.