Should Subaru Use 92 or 95 Octane Gasoline?

[LaBrynlee]

Subaru's turbocharged models use 95 octane gasoline; naturally aspirated models use 92 octane gasoline. More information about 92 and 95 octane gasoline is as follows: 1. The octane ratings of 92 and 95 gasoline represent the fuel's anti-knock performance. The higher the octane number, the greater the isooctane content, indicating better anti-knock performance. 2. The higher the compression ratio, the higher the octane rating of the gasoline used: For engines with a compression ratio greater than 9:1, it is recommended to use gasoline with an octane rating above 90; for engines with a compression ratio greater than 9.5:1, it is best to use gasoline with an octane rating above 92; when the compression ratio is greater than 10:1, it is best to use 95 octane or higher-rated gasoline.

[BenjaminLee]

I bought a Subaru Forester last year and specifically asked the 4S店 technician when purchasing. The fuel cap states 'recommended 92 octane or higher unleaded gasoline,' and the manual clearly states that 92 octane is sufficient. I've driven 20,000 kilometers always using 92 octane, with no power issues and saving on fuel costs. However, for turbocharged models like the WRX, the 4S店 recommends 95 octane, as turbo engines have higher compression ratios. When refueling, always check the specific model and manual instructions—don't be swayed by gas station promotions to use higher octane unnecessarily. Using the wrong fuel might only cause slightly weaker performance in the short term, but long-term use could increase carbon buildup, so following the manufacturer's guidelines is safest. Remember, choosing a reputable gas station is more important than the octane rating—even 98 octane from small stations isn't as reliable as Sinopec or PetroChina's 92 octane.

[VanRyder]

I've worked on many Subarus before, and this issue depends on the engine model. For naturally aspirated horizontally opposed engines like those in the Forester, 92-octane gasoline is perfectly sufficient—the compression ratio is calibrated for 92. However, for turbocharged models like the Outback 2.4T or WRX, the manufacturer's manual explicitly requires 95-octane or higher. This is because turbocharging increases cylinder pressure, and lower-octane fuel can cause knocking. Always check the owner's manual in the glovebox or the label inside the fuel filler cap before refueling. Don’t be misled by claims that higher-octane fuel is cleaner—using 95 in a naturally aspirated engine is just a waste of money, but running 92 in a turbocharged engine can damage the piston rings. As a side note on fueling habits: try to stick to one gas station and avoid alternating between 92 and 95 octane.

[McRyan]

As a long-time Subaru owner, I've driven my XV for over five years. The experience tells me that naturally aspirated models are perfectly fine with 92-octane fuel – the boxer engine isn't that delicate. But for turbocharged models like the WRX, 95-octane is mandatory; this isn't an area to cut corners. The most practical habit is checking the fuel filler cap before refueling – its labeling is far more reliable than online rumors. Using higher-octane fuel long-term offers no benefits for naturally aspirated cars and may even cause incomplete combustion, whereas low-octane fuel in turbocharged models can disrupt ignition timing. A quick reminder on refueling timing: don't wait until the fuel gauge hits empty. The fuel pump relies on gasoline for cooling – running too low shortens its lifespan.