i'm not too sure on how it effects your a/f ratio, but i do know that putting some 110 in at the strip and running right then and there, really isnt doing much.. for 1, the computer isnt used to the new gas being burnt yet, and 2, the whole reason to put high octane in, is to being able to advance your timing.. ive seen a few people do it, but most dont.. it may help a little bit, but not as much as it can.. and to try and answer you question from just basica knowledge, i dont see a reason for it effecting it.. the injectors/pump arent pumping more fuel into the cylinders, the fuel just has a lower?? flash point.. thats just what i would assume.. spic's lookin it up so i could be wrong..