higby5

When I was young Sunoco had a fuel called Sunoco 260 , it was blue in color and it was 100 0ctane. I used it in my 1967 , 396 Camaro. Cost 5 bucks to fill the tank. Anyone who had a muscle car in the 1960's used it. If I were going to put 100 octane gas in my Audi , I would simply call the service dept at a few Audi dealerships and get the opinions of several service mgrs. I would love to run that stuff in my Allroad!

M0J0

https://www.aaa.com/autorepair/artic...ne-and-quality

This is actually a good run down. Basically, if your engine does knock you should raise your octane level. I never noticed any knocking on my M3 with a 12:1 compression ratio at 87 octane. Though I do admit I ran 89 to be safe. Octane has nothing to do with more power. It has to do with anti-knock. Also, bad fuel has nothing to do with the octane level.

As for running 100 octane you would have to get a new tune to take advantage of it. In old cars you could simply advance the timing. Modern engines can adjust the timing on the fly which is why they rarely knock with a lower fuel grade. Is this gas station near a track? Lots of cars have race tunes for 98+ octane to run at tracks. Higher octane does not produce more power or better mpg. It can produce more power with a tune, but that is a different story. I am skeptical about a tune giving better mpg. Modern engines are tuned to give out the least amount of emissions possible. They are usually under tuned for power and I guess it is possible they take a tiny hit in mpg to meet federal emissions standards.

breadbooze

I disagree with octane having nothing to do with more power. The confusion here is that gasoline, regardless of octane, contains the same amount of stored energy. Higher octane allows for more advanced ignition timing, higher octane fuel burns slower, and by advancing ignition timing there is more time for the air/fuel mixture to achieve maximum cylinder pressure, therefore providing more torque (power). Turbochargers alter effective compression ratios thus adding another layer of variables to the combustion cycle.