[DannoXYZ]

Originally Posted by Triple Jim

Not according to this comparison: https://www.superstreetbike.com/more...busters#page-2

Of course dynamometers can be made to prove about anything the operator wants to prove.

Yeah, on EFI engine, it's all a wash unless you re-program ignition-map with more advance to take advantage of higher-octane fuel. Which precludes going back to lower-octane without re-programming again.

I think dyno-comparisons I'm thinking of is +10yrs old on carb engines. NA engines make max-power around 13.5:1, richer or leaner on either side tends to drop power. The difference in AFR with running richer would account for loss of power. The primary octane-boosting hydrocarbon in higher-octane fuels is toluene which has higher specific-gravity than 87-octane gasoline mix, which causes richer mixtures.

If Dustin is worried about ill-effects on carbs, he should be looking more at RVP-Reid Vapour Pressure rather than Octane properties of gasoline. The winter-blends of gas tend to have higher RVP for easier evaporation and lower emissions. This causes gasoline sitting around to dry out faster and clog carbs easier during winter storage. Using some additives like Stabil-360 is a simple fix.