[Bruce Edwards]

Any of them will raise the boil point. The whole trick is in making the fuel burn slower. A lower octane will burn faster and under compression will self light, thus the ping sound, the slower burning fuel will not self light as it is not as prone to burn thus it will not cause the ping.
Winter fuel is made to burn at a lower point than summer blends as the cold air does not mix well with the fuel so they make it so it will evaporate faster and mix with the air. Fine when it is 40 out but really bad when it is 90+.