Rocky Mountain High.....octane

Worth knowing? Perhaps

https://www.youtube.com/watch?v=kJyd6C99_3g

 

Thanks for sharing this @Moon Landing. Living in CO there's always debates on this topic. Shared this on our FB group.

 

Ngl, I used 85 trash gas in mine for almost 8 years without any problems.

 

Modern cars also have knock sensors and many have variable valve timing. So your engine may still run fine - maybe a bit less power. I think this is also why you can now use regular fuel in a lot of modern engines that have higher compression ratios than in times of yore.

 

Here’s another take on why to use lower octane at higher elevation (i.e., less oxygen):
See post 102.
https://www.4runners.com/threads/why-is-puerto-rico-able-to-use-15w-40.18928/page-4#post-257049

 

One would think manufactures who offer vehicles there have tweaked them to operate satisfactorily at those octane levels. one would think

 

Yeah, what @BroRunner said.
The richer air/fuel mix at high elevation probably made a bigger difference with older carbureted cars. Newer fuel injected cars with all the computer control can compensate for a lot of conditions, within limits. Our 4Runners are such dogs you’d probably never notice any difference with a lower octane unless you were pulling a heavy trailer uphill at full throttle.

 

Better rich than lean.

 

I grew up in the San Francisco Bay Area. Maybe 200'MSL. My parents had a couple of really nice little cabins just off the highway between Truckee and Reno, in the Donner Pass. We would go up there once or twice a winter to play in the snow. The highway was ploughed up to them, and no farther. It always amazed me parking under the snow cliff where the ploughing stopped. Usually taller than my father, or me.
Anywho, we always stopped about 1/2 way there to fuel up (25 cents/gal was outrageous price for gas), and my father would adjust the Ford Galaxy station wagon's carb mixture screw leaner by X turns. I don't recall the exact number, but after as many times we went up there, it was a pretty fixed procedure. Stop and adjust for high altitude operation.

Now, the computers do it all, and both my 4Runners do nicely up here at about 4,500'MSL. My pickup needed a little tweaking to work just right up here, but now, it's doing just as well. If I ever go back to lower altitudes, I'll have to readjust it again. Yes, it has the HAIC system but it just wan't running RIGHT. I remembered my father adjusting and did the same. It worked like a dream. Just took a little testing. Adjust 1/4 turn leaner, drive around a bit, etc.

I do still use the "regular" octane gas. 82, 87, whatever it is locally. I quit looking. My trucks seem to be happy with it, and I'm a cheap SOB. I do wish they'd quit with the friggin ethanol, though.

Have fun all, however high (up) you are
Pat☺