3.6 power loss at elevation

[AKLespaul]

I was going to pick up parts in another town this weekend and wanted to share about power/ response decreases in the 3.6 MT.
I have had the Jeep for almost five years and it has always been about 2 up to 400 ft above sea level. This weekend we were between 4k and 6k in heavy wildfire smoke for 175 miles. I felt a slower response to the pedal, but when it got wound up it did good. Very strange to feel this and after we got back down under 1k it was right back to normal. Snappy and the back end broke loose on wet pavement.
Nice trip, just never dealt with that much elevation rise so fast.
Will the 3.6 re-learn the O2 loss if I lived there? Self adjusting or need a recalibration.
Just wondering....

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[58Willys]

Smoke doesn’t contain much oxygen, but your still sucking it in the air intake; result is decreased performance. I’ve had my 3.6 above 6k several times, runs fine.

 

[maestro5531]

You loose 3% power for every 1000ft of elevation. I just spent a week in CO at around 9500ft of elevation, It felt way underpowered. When I would go down to Denver or Springs, Jeep felt very responsive, when I returned to Shitcago, I could really tell the difference. Boosted engines can compensate to a degree but NA, you simply loose power.

 

[AKLespaul]

Not saying it didn't run good, just slow on the responce. Need more rpm to gain.
No complaints, just sharing.

 

[Ratbert]

Not saying it didn't run good, just slow on the responce. Need more rpm to gain.
No complaints, just sharing.

As others have said: you definitely lose power at altitude, especially naturally aspirated engines.

Some people might claim that they don't really feel the difference, but you lose quite a bit.

 

[Dusty Dude]

You notice it more if you are more aggressive with your driving. If you’re “Sunday driving”, not so much.

 

[Philly_]

Time for a supercharger.

 

[Reinen]

Now you know why nearly everyone who lives at 1-2mi elevation opts for the 2.0T. There's a big difference between the two when you're up high. The 2.0T does have power loss as well but it's much less. Small enough for the trans to make up for it making it very hard to notice.

You don't have to do any relearn or recalibration. The engine will automatically do the best it can with the air it has.

 

[azjl#3]

I live at 6k, at 1,000ft jeep feels extremely snappy, at 6k, not so much, unless you wind it up.

Normal IMO.

 

[COJeff]

It's normal. In Denver we just learn to deal with it.

 

[wingnut60]

From TX, four months in CO at 7-8000’—21 3.6 Sahara HA. Runs very good, does not lose much at this alt. Daily driver, no mods.

 

[Ratbert]

From TX, four months in CO at 7-8000’—21 3.6 Sahara HA. Runs very good, does not lose much at this alt. Daily driver, no mods.

It starts with 285 horsepower. It loses ~3% for every 1,000 feet. That's a ~24% loss of power (~64 horsepower) that you don't consider to be "much at all"???

 

[wingnut60]

I would guess that it’s in my driving habits…maybe I just don’t need all power at lower elevations. I can tell you that there is a 3-4% grade coming out of park entrance and I have no problem getting to 60 in a short distance. Not saying there is no power loss—has to be—I just don’t notice it. Also does excellent at 10-12000’ in mountains. Temp readings are another deal altogether.

 

[Grey24Rubi]

Spent a lot of time on I70 going back and forth between Copper Mtn, Vail, and Beaver Creek. Was actually driving a car with more HP then our Jeep and at those high elevations you definitively notice the power loss. On one of the trips we took my wife's car which has twin turbos and I didn't notice the power loss being as significant but her other car that was naturally aspirated it was, very, noticeable.

 

[roaniecowpony]

Here's some basic information about power vs altitude. The aviation data is based on a "standard atmosphere" , which is 29.92 hg, 59F

Determining Engine Power (kitplanes.com)

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