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In addition to influencing consumption and engine response, Fuel quality has a direct impact on the useful life of components such as spark plugs and lambda sensors.
São Paulo, November 2025 – The increase in the supply of premium fuels at gas stations generates curiosity among drivers looking for more performance and durability for the engine. But is it really worth filling popular cars with this type of fuel?? The answer depends on the type of engine, vehicle calibration and driver expectations.
In popular models with flex fuel engines, the difference between regular and premium gasoline is minimal, since these propellants are adjusted for national fuel, with around 93 RON and up to 30% ethanol. "In this case, premium gasoline does not provide noticeable gains in power or consumption, although its purer formulation reduces the formation of residues and promotes cleaner combustion. In imported vehicles, equipped with gasoline-only engines and higher compression ratio or turbo, the highest octane of the premium version, which can reach 102 RON, ensures more efficient operation and avoids so-called “pin knocking””, explains Hiromori Mori, Technical Assistance Consultant at Niterra do Brasil
On the other hand, Continuous use of low-quality common fuels can cause carbon deposits to accumulate, increasing consumption and wear of parts. Thus, even if the driver does not notice an immediate difference in performance, Prolonged use of premium gasoline tends to keep the engine in better condition. In this context, and NGK, Niterra brand specialized in ignition systems, highlights the differences in performance between fuels - whether premium or not -, in engine operation.
Premium fuel contains less anhydrous ethanol (E25) than regular gasoline (E27–E30), which makes the engine's electronic system adjust the air/fuel mixture more precisely. This can generate a slight improvement in consumption and more stable combustion, especially on road journeys. Furthermore, because it is purer and suffers less adulteration, premium keeps the lambda sensor clean for longer, favoring the correct reading of the mixture and ensuring that the engine always operates in the ideal efficiency range.
Poor quality fuels, with excess ethanol, solvents or impurities, can contaminate the lambda probe and injection nozzles, changing the air/fuel mixture reading. This causes acceleration failures, increase in pollutant emissions, increased consumption and even damage to the catalyst, which loses efficiency and may require early replacement.
While the use of regular gasoline of good origin is sufficient for flex-fuel cars, premium fuel offers durability benefits, as less waste formation, greater resistance to oxidation and extra protection during long periods of inactivity. Vehicles that sit idle for a long time — such as those used only for travel or collectibles — benefit from the greater chemical stability of premium gasoline, which reduces fuel degradation and makes starting easier even after weeks of non-use.
Poor quality gasoline accelerates the formation of carbon deposits on valves and spark plugs., reduces burning efficiency and increases the risk of clogging of injection nozzles. The result is loss of performance, higher consumption and need for more frequent maintenance. In extreme cases, adulterated fuel can compromise the functioning of the fuel pump and injection system sensors.
One of the most advantageous uses of premium gasoline is in the cold start tank. (six pack) of the oldest flex fuel vehicles. Due to its greater durability and resistance to evaporation, Premium fuel prevents starting failures and system clogging. As the volume used is small, the additional cost is low, but the benefit in reliability is high.
The use of common gasoline of poor origin in this reservoir, on the other hand, can cause premature fuel degradation, gum formation and clogging of ducts, making starting difficult on cold days. Over time, the system may corrode and require cleaning or replacement of components.
In cases where the use of poor quality fuels results in failures or the need to replace components, like spark plugs, cabos, coils and sensors, including lambda probe, Niterra offers a complete line of NGK and NTK products to the aftermarket. These components are developed with the same technology applied in the original supply to automakers, ensuring performance, durability, reliability of the ignition and engine control system.
