Gas Mileage a tell of huh? (1 Viewer)

[linuxgod]

Over dozens of trips from Texas to Colorado and many well beyond that, I consistently get better mileage at altitude than near sea level where I live. I assume it has to do with fuel and possibly spark adjustments by the ecu more than thinner air offering less wind resistance.

Likely mostly thinner air resulting in a thinner air-fuel mixture. Also resulting in correspondingly less HP, but most of us rarely notice that difference unless we're racing from a stop light or towing.

You lose ~3% HP per 1000' due to the thinner air and thus reduced amount of fuel used to meet the ~14.6-to-1 A/F target (or whatever the ideal ratio is... I cannot recall offhand. If you don't *need* the extra HP (like when just normally cruising) then you'll get an MPG improvement in exchange

 

[bloc]

Likely mostly thinner air resulting in a thinner air-fuel mixture. Also resulting in correspondingly less HP, but most of us rarely notice that difference unless we're racing from a stop light or towing.

To me the really interesting thing is my truck uses much more cooling fan up around the San Juans, even when it's 20 degrees cooler up there than here at home. Again I presume the thinner air being less efficient at pulling BTUs out of the radiator, so more volume is needed.

But yeah ultimately less oxygen per volume of air means less fuel needed to hit a given ratio.. and it seems this effect is greater than the reduction in horsepower required to push the vehicle through the thinner air.

 

[warm fuzzies]

Agree on all of this and am in the camp of keep as much aero as possible.

I've ordered and am planning on installing budbuilt rock rails to keep for an oem+ look. I've also upgraded tires to KO2s and that's enough for all the wheeling I do up here in Montana. I wish we had more ground clearance but I've driven over some gnarly stuff and as long as I put the tires in the right spots, everything seems to work out fine.

 

[77HesterSue]

Wow, the mileage I get in my 2019 truck is 12.9 no matter what. I got that in my first trip and the same since.