Octane is the ability to stop detonation. The higher the number - the greater the compression you can use in a regular 8:5 / 1 - 9:5 / 1 engine.
diesel fuel on the other hand is rated in Cetane.
Alcohol will cause the fuel to have a higher Octane rating because it doesn't burn as easily as gasoline, but it takes 150 percent of fuel to make the same amount of power as gasoline.
Which means that if you have to burn 10 gallons of gasoline to get from here to there it will take 15 gallons of alcohol to go the same distance.
The richer fuel mixture in the fuel system is what causes it to run cooler - not the fuel itself.
By running a 15 to 1 mix of gasoline to air - like in your Ranger, you are not supplying 150% of fuel like in a Alcohol fuel injection system. So you are actually running the engine LEAN - which will make it run hotter than with plain old gasoline.
The Alcohol - by the way is corrosive - which means that it will cause everything in your fuel system to corrode. The metal gas tank will rust out, the fuel lines will rot out, the fuel filter - which is probably paper will gum up and fall apart. The fuel injectors will corrode and will quit working prematurly.
That is the reason why they came out with Flex Fuel vehicles.
The first time they came out with the Alcohol - back in the 70's, it caused so much damage and so many lawsuits came from it that the fuel companies quit selling it.