We are taking a driving trip this summer to Colorado and will be in an area that is 8500 to 10,000 feet above sea level.

I know the engines in todays vehicles will automatically adjust the fuel mixture to the thinner air. I also know your performance and mpg will go down at the higher altitude.

However, if anyone on this forum has experienced driving at high altitude, or has any other advice, I would appreciate hearing it. Thanks in advance.

 

I wouldn't worry too much about the fuel. It's usually the brakes that take a beating going down those mountains. Keep your auto in a lower gear and don't just use D (Drive). Use the 3 and 2 settings to save your brakes from overheating when descending. Use your engine gearing to help ease the load on the brakes. You will probably see some emergency runoff areas at the bottom of some of the mountains for cars and trucks who have overheated and lost their brakes.

 

These cars don't have turbos so drive it as normal. Your brakes will be fine.

 

Exactly, dont worry about it. I'm from Colorado and go up the mountains several times a year. Using manual mode instead of auto is going to keep you from over speeding down the hills though (you can get going fast in a hurry if not paying attention). And its nice going up the hills to always keep the auto from downshifting. Otherwise, just leave it in auto.

As a side note, I know that cars sold in high altitude areas like CO usually get programed for the thin air. That way the system doesnt try to change the mixture? I dont know, but unless your vehicle is carborated (which it isnt) then you will be fine.

 

Thanks for all your advice. I've already taken trips in my outtie where I've went up and down fairly steep inclines so I'm used to using lower gears to save the brakes, however I suspect I'm going to face inclines in Colorado that are steeper and longer than most.

I'm not worried about the altitude as far as the engine goes, as I know the computer will adjust. However, it will be interesting to see what it does to the mpg.

 

When comparing driving on the highway out on the plains vs. in the mountains in CO, the MPG average is usually better driving in the mountains. What goes up, must come down....

Had a 5 hr trip each way from Denver to the south-west part of the state. Had to go over a few passes. Averaging 65-70mph, got 25mpg on the way there, and 31mpg on the way back. I was happy

 

That makes sense that your mpg would average out (lower going up the mountain, higher going down). When I talked about lower mpg I was thinking about just being at a higher altitude. For example suppose your driving around on fairly level roads in metro Denver or Colorado Springs, but you're at 5,000 - 6,000 feet. Wouldn't your mpg drop a bit because of the thinner air as say in comparasion to Phoenix which is at 1,000 feet?

 

For living in Denver we dont consider Denver, Colo Springs, etc. high altitude. Only when going up in the mountains we do. I'll just leave you some quick numbers. When driving around these cities these are the averages I get:

city driving: 18mpg
city w/ highway: 22mpg
highway @ 75-80mph: 22-24mpg
highway @ 65-70mph: 25-30mpg

Going 65mph in the outtie is the money spot. It gets awesome mpg.

 

Thanks again for the information. One final question. I briefly lived in Salt Lake City (4500 feet above sea level) a few years back when the company I was working for transferred me there, and noticed something strange at gas stations.

Gas stations there had 85 octane as the lowest of the 3 grades and being from Phoenix I was used to 87 octane as the lowest grade. I only used 87 octane in my car, but a co-worker told me 85 octane would work fine in the higher altitude and not harm the engine. I had never heard this before so I'm wondering do gas stations in Denver or Colorado Springs offer 85 octane or do they have 87, 89, 91 octane as the 3 grades like stations here in Phoenix.

 

Pretty strange from EU perspective. If you searched very hard maybe you could find some station that sells 91...
The worst what we have here is 95 there is also 98 and 99...