Which is more prone to carbon buildup, 92 or 95?
2 Answers
Gasoline grades 92 and 95 have little correlation with carbon buildup; it's more related to the vehicle model. The amount of carbon deposits produced by the same quantity of 92 and 95 gasoline is roughly the same, as their basic composition is identical. The gasoline grade primarily corresponds to its anti-knock performance. The main difference between the two grades lies in the octane rating's anti-knock properties. Mixing 92 and 95 gasoline generally doesn't cause significant issues, and the immediate effect may be slightly improved combustion. However, if the vehicle manual recommends using 92, the engine's heat output from fuel-air mixture combustion is already calibrated for 92 gasoline. Switching to 95 might theoretically not reflect the vehicle's optimal performance, possibly resulting in only a slight momentary boost in power. Carbon buildup mainly occurs due to incomplete fuel combustion in the engine or the presence of non-combustible paraffin and gum substances in gasoline, which leave residues in components like fuel injectors, throttle valves, fuel lines, and spark plugs. Under high temperatures, these residues transform into carbon deposits. Symptoms of carbon buildup in the intake system include higher idle speed, abnormal idle vibrations, poor acceleration, increased fuel consumption, and excessive exhaust emissions. During engine operation, carbon deposits form from the gum residues left by incomplete combustion of the air-fuel mixture, adhering to the cylinder head and around the spark plugs, disrupting normal cylinder operation and reducing engine performance.
I've been driving for fifteen years and often discuss gasoline with friends. The 92-octane gasoline is cheap and widely available here, and many people use it. However, if you refuel at a low-quality station with fewer additives, carbon deposits may increase. The 95-octane is a bit more expensive but usually contains better additives to clean the engine, resulting in fewer carbon deposits—especially for cars with high compression ratios. Long-term use of 95-octane makes the engine feel cleaner. Also, driving habits have a bigger impact—like aggressive acceleration or irregular maintenance. Whether you use 92 or 95, carbon deposits will rise quickly. I recommend following the owner's manual for refueling and avoiding low-quality fuel to save money. A weekly highway drive can also help flush out carbon deposits. Overall, 92-octane is slightly more prone to carbon buildup, but the difference isn't significant—just ensure the gas station is reliable.
