Yep, you guys are right on the money. Octane or Octane Number Rating (ONR) reflects the antiknock characteristics of the fuel and is NOT synonymous with power.
About four or five years ago, one major oil company ran a (I thought) misleading TV advertisement. It showed a Vette accelerating with "normal" octane fuel, then they ran it again on their "super premium" fuel. It ran quicker on the higher octane fuel.
What they didn't tell you is that the Vette (at least then) had a knock sensor. The comptuer was programmed to "listen" for knocks. If none were heard, it would advance the spark timing 2°, then listen again. Since it was in effect tuning to the fuel *increased spark advance*, there was a performance improvement.
As you correctly pointed out, the blend of fuels and/or additives necessary to increase octane cause the fuel to contain less heat energy. I'm fairly sure that this accounts for the loss of performance many of you experienced with the higher octane fuel.
Gasolines tend to exhibit different anti-knock characteristics when run under load in the engine than they do at cruise. RON (Research Octane Number) is the result of a steady-state cruise test. Another octane rating, called MON (Motor Octane Number), is tested under high speed and high temperature conditions.
The octane number test was developed in the 1920’s and is still used today. A particular fuel that is to be rated is run in a CFR (Cooperative Fuel Research) engine. This special one-cylinder engine, also called a “knock engine”, has an adjustable combustion chamber so that most any fuel can be squeezed until it detonates. Fuels are tested and compared to ISO-octane, that has been assigned an AKI (anti-knock index) of 100.
In the late 1960’s, the US Congress standardized an octane number rating (ONR) system for passenger car motor fuels that is an average of the RON and MON (thus the R+M/2 displayed on the pump).
In racing, we are less concerned about the performance of the engine at cruise. For this reason, racing fuels are usually listed by their slightly lower MON rating. This means we may have an "apples & oranges" problem here on the quoted ONR's of these fuels.
110 Octane is a really high rating--and if true, it could handle extremely high dynamic engine compression ratios. However, if you don't plan on changing pistons or combustion chamber sizes to put the squeeze on the fuel/air mixture (or supercharging), you'll be better off running pump super premium.
For what it's worth, the street racers around here seem to prefer the Amoco Super Premium and it's what I run in my Viper.
