Airports and buildings in Denver, etc. - also similar lack of oxygen due to high altitude, or is the internal air different?

[ParallelLines]

Part of a discussion of the altitude - octane argument from a prior thread of mine:

Future EV/Hybrid Plans, AWD edition!

Here is this, if you feel like a white board lecture about it. Old, like really old, cars needed about 2 less octane per 1000 feet of elevation, but for anything made in the last 40 years it is closer to a 0.2 octane less per 1000 feet. 85 probably won’t damage your car, but it is also not what the car was designed for. [Never Use This Gas In Your Car!]

So… IMHO, a holdover from 40-50 year old figures, though there is still some effect. For that matter, most modern computer controlled ignitions will compensate to a large degree. My calculation was using the math in the video presented, at Colorado Springs altitude (6k) there was still the argument for about 1 octane’s worth of difference, but… LOTS of different information online.