DocFuller

Just moved to Colorado Springs from D.C. and noticed a little more sluggishness than normal. I have a CAI only, and running 91 octane to see if that helps. Banged on both cats under '07 Unlimited X, heard a little bit of 'junk' in there. I know fuel injection/computer is supposed to automatically adjust ( new plugs and oil change recently ), but maybe altitude still affects stuff? Not talking steep-graded hills, either... 58,000 miles- manual trans.

JKLarson

I'm guessing altitude...a lot less oxygen at 6,000 feet than at sea level...welcome to Colorado!

ronjenx

Higher altitude = less air into the cylinders = less fuel injected = less power.

It also means you can use lower octane gasoline because the higher altitude is similar to lowering the compression ratio.

Ludo

I moved Colorado Springs to Houston in july. my jeep was sluggish up there also. Mine had a hard time with climbing long hills, i would have to downshift to 4th to make it up the hill at Powers BLVD and Barnes heading north. It felt like i had a 4-cyl. Once i moved to Houston i noticed better throttle response, more power, and a deeper tone in the exhaust. so I am thinking high altitude but i have had the dealership change my o2 sensors 3 times due to it stalling while at a red light.

mine-
3.5 in lift
35" duratracs
4.56 gears
manual tranny
38,000 mi.

oh by the way if your in the military check out Military jeepers of colorado springs.Colorado Springs

JKLarson

HP Loss = (elevation x 0.03 x horsepower @ sea level)/1000

For Colorado Springs (approx. elevation 6000 feet), I'm assuming you have a 2011 or earlier with 58,000 miles on it = 202 HP for the 3.8 L:

(6000 x 0.03 x 202hp)/1000 = 36hp loss

Now you are running around 166 HP...

I have a 2012 with the 3.6 and live in Denver:

(5500 (average el.) X 0.03 X 285hp)/100 = 47hp loss

Now I'm running around 238hp...

ronjenx

My first car had only 36 hp to start with.

Thanks for the formula.

Rob50lx

Don't forget about the DA (density altitude) of our air. Living in the Springs usually has a DA of 8,000ft +. So our air quality in regards to performance sucks. Also if you came from a place that had straight gas without ethanol; you are taking another performance/mileage hit.

When I moved here from Florida 6 years ago; I was shocked how much the gas and altitude killed the performance in my 2 Jeeps and Mustang. I brought several Jerry cans full of good 93 octane Florida gas. When the gas ran out, I noticed a 2mpg decrease in the Jeeps besides the 1mpg decrease from the altitude. The Mustang took such a performance hit that I made significant changes to the engine to regain the lost performance.

I was never a fan of forced induction until I moved here. I didn't like the added heat, complexity, or weight to the nose of the car. Now I am considering adding a blower to my JK and Mustang.

Rob

DocFuller

[QUOTE="JKLarson"]

HP Loss = (elevation x 0.03 x horsepower @ sea level)/1000

For Colorado Springs (approx. elevation 6000 feet), I'm assuming you have a 2011 or earlier with 58,000 miles on it = 202 HP for the 3.8 L:

(6000 x 0.03 x 202hp)/1000 = 36hp loss

Now you are running around 166 HP...

Holy loss of testicles, Batman!

DocFuller

So I'm just wasting money running 91 octane with Superchip? And will dyno-ing her bring her back to 'normal' power production??? I'm gonna be here a few years, so the cost may be worth it...

Ryan0260

Volkswagen?