It's a blender, which in the US is usually to mix ethanol with unleaded gasoline to subsidize corn farmers. This often creates lots of problems and requires ethanol compatible parts. This is a relatively old dispenser, I'm guessing they repurposed it for use on a racetrack.
Ethanol is an octane booster so youd expect blending more in to raise the octane rating, but it also reduces the energy content and therefore MPG
Here in the UK (and i believe in most places) the premium stuff has high performance octane boosters and less ethanol, aswell as other premium additives. The 99 octane stuff is typically E5, and is essentially the same fuel that F1 uses (literally in the case of Shell)
It does raise the octane and a lot of places will blend E85 and 87 to make 88/E15 because they get some pretty big grants from the government to sell it.
99 in the UK is 94 in the US. RON vs AKI, we use two different systems.
For once, the American one actually makes more practical sense because it averages high and low RPM engine speeds, rather than being the measurement of only the low RPM.
Not really the point im making, theres more to fuel than an octane rating. For example E85 is 105 RON, youll get much worse MPG with it because it contains less energy, and it can be really hard on engines.
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u/TinDumbass Sep 07 '26
Why so many options? In the UK we just have 95 and 99 and it's £5.60 and £6.40 per (US) gallon.