Will using 92-octane gasoline in a car designated for 95-octane have any impact?

[Catalina]

Using 92-octane gasoline in a car designated for 95-octane will have an impact. If 92-octane gasoline is used for an extended period, it can cause certain damage to the car's engine, and in severe cases, may even lead to engine failure, rendering it beyond repair. The reason cars specify a particular octane rating is due to differences in engine performance. Cars that require higher-octane gasoline generally have engines with better anti-knock properties. If an engine is designed for 95-octane fuel, it must use 95-octane gasoline. Prolonged use of a lower-octane fuel can affect the car's ignition system, fuel injectors, and spark plugs, potentially leading to issues such as engine shaking, bent valves, or damage to the valve cover. There is no difference in fuel quality between 95-octane and 92-octane gasoline. Typically, high-compression engines require higher-octane fuel. 92-octane gasoline has an octane rating of 92, while 95-octane gasoline has an octane rating of 95. The chemical compositions of these two fuel types are quite similar, but 95-octane gasoline offers higher fuel efficiency and provides more robust power for the vehicle. Generally, naturally aspirated cars use 92-octane fuel, while turbocharged cars require 95-octane fuel.

[VonSebastian]

Last time my buddy accidentally filled his turbocharged car with 92 octane instead of the required 95. Within two days, the engine started acting up—idling rough as a sieve and making metallic knocking sounds like banging on a tin bucket during hard acceleration. The mechanic diagnosed it as engine knock, caused by 92's poor anti-knock properties prematurely igniting the air-fuel mixture under high temperatures, throwing piston movements into chaos. Now he has to clean the fuel injectors every 5,000 km, and long-term use could lead to carbon buildup clogging the catalytic converter. If you must use 92 in an emergency, add a fuel additive as a buffer, but never make it a habit. Always follow the fuel grade specified on the fuel filler cap—saving a few cents per liter could cost you an engine rebuild later.

[JonathanMarie]

My German car has been running on 95-octane fuel for years. Once during a long trip when I couldn't find a station with 95, I reluctantly filled half the tank with 92-octane. I immediately noticed the power felt sluggish - even flooring the accelerator on hills produced weak response. Later at the dealership I learned that while the engine ECU can slightly adjust ignition timing to accommodate lower octane fuel, it's like asking a marathon runner to switch to plain congee - the engine can't perform at its full potential. The biggest headache was the 15% increase in fuel consumption, which meant no actual savings. Now I always check gas stations via mobile apps beforehand, and I double-check the octane rating on unfamiliar pumps. I recommend everyone get in the habit of checking their fuel manual - don't put your car through unnecessary strain and extra costs like I did.

[SanDamian]

Using 92 octane is absolutely not acceptable. The main difference between 95 and 92 is the octane rating, and high-compression engines require gasoline with higher anti-knock properties. My relative's car had the check engine light come on after using the wrong fuel, and the diagnostic code indicated cylinder misfire. The repair shop said the low-octane fuel caused the combustion chamber to overheat, deforming the valves. If you accidentally fill up with the wrong fuel, you should immediately dilute it with higher-octane gasoline. Newer cars have knock sensors that can temporarily adjust, but this is only a temporary fix. The safest approach is to always follow the manual's fuel recommendations.

[LaAaron]

My neighbor's old BMW suffered from this before. After mixing 92-octane fuel into the 95-octane tank, black smoke poured out of the exhaust pipe during cold starts. The mechanic found the piston tops covered in thick black carbon deposits when disassembling the engine, saying the lower-octane fuel burned incompletely, even poisoning and disabling the oxygen sensor. Now he always triple-checks the fuel pump nozzle when refueling and records the mileage and gas station for each fill-up. If he notices sluggish acceleration or a sudden spike in fuel consumption, he immediately checks the fuel quality. Actually, gas stations occasionally unload the wrong fuel tank, leading to octane rating mismatches, so keeping fuel receipts is essential.