Octane and Altitude

[spy52]

While living in Savannah Georgia (sea-level) I installed a Demolet CAI with an excalibrater II tune for 91 Octane. the tunes included wer 89, 91, and 93. I had no problem finding 93 Octane to fit the Demolet specs and felt a difference in my power. I tuned for 91 to compenstae for any fluctuations in the 93 Octane gasoline (err on the side of caution).

I have since moved to Denver, Colorado (5000+ft) and because of some science mumbo-jumbo altitude BS they do not produce 93 Octane gasoline. The highest one can get is 91 Octane. Consequently, I had to tune my car down to 89 in order to compensate for the lack of Octane. This begs the question of whether it is even worth it anymore to have the CAI if I can't use a quality tune with it.

Does the altitude compensate so much that I could safely go back to a 91 or even 93 tune with the 91 octane present here?

For example, I knew a guy who had an eclipse a few years ago that required he use premium gasoline. That's all it said, it never mentioned an octane. Even though there could be a significant difference between the premium octane in Georgia and Colorado. Surely the car wasn't damaged for using lower octane fuel in Colorado, otherwise they woudln't be able to sell the car here. Right? So theoretically, I could use a 93 tune with a 91 octane because of altitude here in Colorado... maybe?

Some big brain help me out with this.

 

[DMZ]

I live in Salt Lake which in the valley varies about 4200 to 4800 feet. Moved out here in 1989. You wont find 93 Octane at these elevations. Because you dont need it.
As you go up in elevation your chances of detonation diminish accordingly due to less dense air. You shouldnt have a problem running 91 with a 93 tune. Octane is added to gas to slow the burn and to keep detonation from happening. Hot summer weather run the 91. Winter, if you drive it run 87 or even 85. If you want to feel safe and maybe go to the drags on a hot night, just add a little octane booster but I doubt you need to. Any car will perform its best with the least amount of octane needed to control detonation. If you hear detonation, and its most likely on hot traffic type days, under load(with your foot in it) then work accordingly. By the way, it sucks up at these elevations with NA cars! Your qtr mile times from where you are compared to where you were, will drop almost a full second and trap speed will be down about 4-5 mph.( all things being equal)
Just keep an ear out and pay close attention on those 90 plus days esp. when in hot city traffic. But in those cases your foot isnt in it anyhow.
Hope this helps!