[Blacky]

Good day all, I’m wondering if this new 2.4 flat four engine, without turbo, runs properly on regular to mid-grade (87-91) octane fuels, thanks.

 

[apex]

Welcome @Blacky

The current 86/BRZ requires it (AFAIK) and even felt sluggish with 91. With this 2022+ model being higher output I'm sure it will require it too. Using the recommended octane rating is always you best option, even if it costs you a few bucks more a tank.

 

[Tōge]

Generally, premium fuels with a higher octane number have better and more additives. If the manufacturer recommends 98 (EU) fuel, do not pour 95 (EU). You can do the other way, but it doesn't do much.

 

[Blacky]

Welcome @Blacky

The current 86/BRZ requires it (AFAIK) and even felt sluggish with 91. With this 2022+ model being higher output I'm sure it will require it too. Using the recommended octane rating is always you best option, even if it costs you a few bucks more a tank.

Apex, thanks - Summing up; So would you agree, its not the FA24 engine, HP or Torque it’s the 13 to 1 compression ratio primarily that dictates octane requirements?

 

[Haskins]

Apex, thanks - Summing up; So would you agree, its not the FA24 engine, HP or Torque it’s the 13 to 1 compression ratio primarily that dictates octane requirements?

I don't know how you can separate the engine and the compression ratio so I'd say it's both and how how Toyota and Subaru have tuned. In general higher grade gasoline/petrol is better fo performance engines. Even if it's not recommended I'm going to go with premium fuel over lower options.

 

[Blacky]

I don't know how you can separate the engine and the compression ratio so I'd say it's both and how how Toyota and Subaru have tuned. In general higher grade gasoline/petrol is better fo performance engines. Even if it's not recommended I'm going to go with premium fuel over lower options.

Agreed, both comp and HP need to be addressed together, now we all await these new rolling toys!

 

[DQ Tiny]

When I had my BRZ tuned it got tuned for 98 octane European gasoline. The tuner was very extensive in his work and in the end tweaked the engine quite a lot resulting in a very noticeable power gain although I must say the tune came with a header and full exhaust change. He did say definitely never put in 95 anymore.
I think the new BRZ/86 requires a higher octane already from the factory but if not; I’ll definitely do this kind of tune again although I might skip the exhaust and header if possible.
Premium 98 or higher gasoline in Europe is better for everything than 95 as it is a lot less hydroscopic and degrades slower than 95 because of the lower alcohol content.
Having said that; I read an interesting artikel about how somebody distilled drinkable alcohol from 95 gasoline at a reasonable price. So it does have it’s uses.