Should the Magotan 1.8T use 92 or 95 octane fuel?

[VanDallas]

The Magotan 1.8T should use 95 octane gasoline, as this fuel grade is recommended in the vehicle's official user manual. In addition to checking the appropriate fuel grade in the user manual, the Magotan 1.8T also has this information indicated on the fuel tank cap. Typically, the fuel 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 application of new technologies, the fuel grade can no longer be solely determined by the compression ratio. High compression ratio engines can also be tuned to use lower octane fuel due to factors such as ignition timing, turbocharging technology, and Atkinson cycle technology. Generally, the higher the 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 the Magotan 1.8T occasionally uses the wrong fuel grade, simply switching back to the correct grade after consumption is sufficient. However, long-term use of the wrong fuel grade can have the following effects: For vehicles designed for lower octane fuel, using higher octane fuel will not cause damage, but the increase in octane number 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 fuel, using lower octane fuel can cause engine knocking. The significantly lower octane number lowers the fuel's ignition point, causing premature ignition during the compression stroke. If combustion occurs before the spark plug fires, resistance is generated during the upward stroke. This resistance makes the engine run very unstably. Mild knocking may only increase noise without significant engine damage, but severe knocking indicates serious engine conditions, affecting not only driving stability but also causing abnormal wear on pistons and cylinders, and in extreme cases, cylinder scoring.

[AveryFitz]

I previously drove a car with a 1.8T engine, like this Magotan. I once tried using 92-octane fuel, and soon felt the car lacked power, with slight knocking sounds during acceleration—likely a detonation issue. Turbocharged engines require high-octane fuel to prevent detonation and protect components. Switching to 95-octane noticeably improved smoothness and even slightly reduced fuel consumption over time. While 92-octane is cheaper, engine repairs could cost much more if issues arise. I recommend sticking to 95-octane, especially during frequent driving or uphill climbs. By the way, checking the owner’s manual shows the manufacturer recommends 95-octane, which greatly helps maintain engine longevity.

[HannahDella]

As someone who frequently repairs cars, I've encountered many turbocharged engine owners asking similar questions. Engines like the Magotan 1.8T are designed with 95-octane fuel as the standard. Lower-octane 92 fuel is prone to knocking under high pressure, which can lead to internal engine damage or reduced power. Using 92-octane in an emergency is acceptable, but long-term use will shorten the engine's lifespan. For safety reasons, it's recommended to only use 95-octane. When choosing fuel, don't just go for the cheapest option—consider the overall cost.

[SanGabriella]

If cost-saving is the priority, 92-octane gasoline is indeed cheaper by a few yuan per liter, but fuel consumption tends to increase after using it. In the long run, the savings aren't significant. I've experienced using 92-octane in my Magotan—it lacked power during acceleration and felt sluggish on highways, negatively impacting the driving experience. Although 95-octane is slightly more expensive, it better protects engine performance. I recommend prioritizing 95-octane and only using 92-octane as a short-term solution when 95 is unavailable. From an economic perspective, higher-octane fuel has its advantages.