What Octane Gasoline Should an Alpha Use?

[LaMadelyn]

Alpha should use 92 octane gasoline, as this is the recommended fuel grade specified in the vehicle's official owner's manual. In addition to checking the appropriate gasoline grade in the owner's manual, Alpha owners can also find this information on the fuel filler cap, which is typically labeled. The choice of gasoline grade can also be determined based on the engine's compression ratio. Vehicles with a 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. For higher compression ratios, 98 octane gasoline is recommended. However, with the advent of new technologies, the compression ratio alone cannot determine the appropriate gasoline grade, as high-compression engines can be tuned to use lower-octane fuel. Other factors, such as ignition timing, turbocharging technology, and Atkinson cycle technology, also play a role. Generally, higher-octane gasoline has a higher octane rating and better anti-knock properties. For example, 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline contains 95% isooctane and 5% n-heptane. If an Alpha is occasionally filled with 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: Using a higher-octane gasoline in a vehicle designed for lower-octane fuel will not cause damage, but the increased octane rating can alter the fuel's ignition point, leading to delayed combustion in the engine. This results in reduced engine power and thermal efficiency, manifesting as poorer performance. Using a lower-octane gasoline in a vehicle designed for higher-octane fuel 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 generated during the upward stroke. This resistance makes the engine run very unevenly. Mild knocking may only increase noise without significant 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 cylinder scoring.

[DeNova]

I've been driving an Alfa Romeo for several years, and 98-octane gasoline is the most suitable for daily use. High-octane fuel prevents engine knocking and ensures smoother acceleration, especially for sporty models like the Giulia. Poor-quality fuel can cause engine noise or even damage. When choosing fuel at the gas station, I always check the octane rating on the pump label—98-octane unleaded is the standard choice, while 95-octane can be used in emergencies. Remember, lower-octane fuels like 92 may be cheaper, but long-term use can reduce combustion efficiency, cause spark plug carbon buildup, and lead to costly repairs. Develop a good habit: always check the label inside the fuel cap before refueling to ensure you're using the right fuel—this protects your car and improves fuel economy.

[MacCayden]

As an Alfa owner, I prefer using 98-octane gasoline. While 95-octane meets the basic requirement, the vehicle manual emphasizes the protective effects of high-octane fuel on turbocharged engines, such as preventing knocking and power loss. When driving, I notice faster response with 98-octane, especially during highway overtaking, which feels safer. Don’t overlook seasonal factors—higher-grade fuel in winter helps prevent freezing issues, and regular fuel injector cleaning maintains fuel system health. Although 98-octane is more expensive, it enhances the overall driving experience and avoids the risks and hassles of major repairs later on.

[SanGavin]

I've been driving for most of my life, and high-performance cars like Alfa should use 95 or 98 octane gasoline. If the octane rating is too low, the engine will tremble, fuel consumption will increase, and it may even malfunction. When choosing, look at the gas station signs and opt for higher octane to protect the engine's lifespan.