What does the fuel grade 929598 mean for experienced drivers?

[JaxonFitz]

In fact, these numbers represent the octane rating of gasoline. The higher the number, the higher the octane rating, indicating better anti-knock performance of the gasoline. Here is some information about gasoline: 1. Introduction: Gasoline is a volatile and flammable hydrocarbon mixture liquid obtained from petroleum through distillation and cracking, used as fuel. It appears as a transparent liquid, is flammable, with a distillation range of 30°C to 220°C, and mainly consists of C5~C12 aliphatic hydrocarbons and naphthenes, along with a certain amount of aromatic hydrocarbons. 2. Classification: Gasoline has a high octane rating (anti-knock combustion performance) and is divided into grades such as 89, 90, 92, 93, 95, 97, and 98 based on the octane rating. Starting from January 2012, the gasoline grades 90, 93, and 97 were revised to 89, 92, and 95.

[VanAyla]

Back when I worked as a mechanic, I often heard drivers talking about 92, 95, and 98—essentially, these numbers refer to gasoline octane ratings. The higher the number, the better the knock resistance. You've got to treat your car like raising a child—turbocharged or high-compression engines need 95 or 98, otherwise, engine knocking will damage the machine like a persistent cough. Naturally aspirated engines are fine with 92; forcing 98 into them leads to incomplete combustion, more carbon deposits, and wasted money. The safest approach is to check the back of the fuel filler cap—the manufacturer has already marked the recommended octane rating there. Don’t fall for myths like ‘higher octane means cleaner fuel’—octane rating has nothing to do with fuel cleanliness.

[Isaiah]

Uncle Zhang, my neighbor who has been driving trucks for thirty years, was chatting with me about this at the gas station last week. The difference between 92, 95, and 98 is like the alcohol content in baijiu: 92 is your regular Erguotou, while 98 is like Moutai—it depends on the engine's 'alcohol tolerance.' Old trucks can run just fine on 92, but a newly bought SUV with a higher compression ratio might 'get dizzy' and knock if fed low-octane fuel, so 95 is the minimum. The gas station promo claims 98 delivers more power? Actual tests show a difference of just a few tenths of a second per 100 km—hardly noticeable in daily driving. What you really need to watch out for is mixing octane levels, especially blending ethanol-blended gasoline with regular fuel, which can make your car throw a tantrum and light up the check engine light.

[StStephen]

A personal lesson learned: Last year, I tried to save money by filling my Civic with 92-octane gas, and the engine started rattling like a drum set. The mechanic found pitting on the pistons upon inspection. Gasoline octane ratings essentially indicate anti-knock indexes—high-compression engines need higher octane to buffer combustion pressure. For European cars like Mercedes and BMW, using 95-octane is standard. But for naturally aspirated Japanese cars, 92-octane is more than enough; forcing 98-octane is just paying the 'IQ tax.' Here’s how to match fuel to your car—turbocharged cars should stick to 95+, naturally aspirated cars are fine with 92, and hybrids should follow the manual. If the gas station tries to upsell you fuel additives? Check your carbon buildup first.