it,s when you have high compression is when you need to cool the burn down , so that is why you would use a higher octane , for higher the octane the cooler the burn . but remember the higher the octane the hard to start a cold engine in low temps
mixing av gas or race gas don,t give you what you mite think say 50/50 race gas c110 mixed with 92 octane you would think you would get something in the middle say 100 octane but you don,t it would be closer to 95 them 100