RE:Driving in Colorado Question

[BLKLT4]

REriving in Colorado Question

Me and a coworker were debating how driving in Colorado would effect an XJ. I know that with a lift and tires the altitude and hills would make a difference in how it would perform. But the question is just how much compared to a stock one? I really have no idea. I've not drove my jeep in colorado.

 

[RTicUL8]

Re: Driving in Colorado Question

Me and a coworker were debating how driving in Colorado would effect an XJ. I know that with a lift and tires the altitude and hills would make a difference in how it would perform. But the question is just how much compared to a stock one? I really have no idea. I've not drove my jeep to colorado.

Driving in Colorado makes your Jeep look better. :thumbup:

Hmmm -that's about all I got...

 

[YELLAHEEP]

Re: Driving in Colorado Question

Well, the above is true..... an XJ always looks better in Colorado. :thumbup:

But the question is kinda silly. A stock cherokee will always out perform a lifted one with bigger tires and no engine mods. A stock XJ will run circles around a lifted XJ no matter where you're at. That's a no brainer.

Gears may help, but for the most part, they lower the rpm range on the road.

Altitude just makes it all that much harder for the engine to perform as there's less oxygen in the air/fuel mix.

Elementary my boy.

 

[old_man]

Re: Driving in Colorado Question

IIRC power loss is 3% per 1000ft.

 

[BLKLT4]

Re: Driving in Colorado Question

My coworker is saying that the difference would be half the performance. Where a stock XJ would be able to do 60 mph a lifted one would ony be able to do 30 mph. I find that hard to believe.

 

[DaJudge]

Re: Driving in Colorado Question

Driving in Colorado makes your Jeep look better. :thumbup:

Hmmm -that's about all I got...

Remember..."If you don't have your looks, you don't have anything!"

 

[BLKLT4]

Re: Driving in Colorado Question

I understand that the altitude and the hills make it harder on the vehicle.I also understand the handicaps of a lifted one. You are misreading my question. My question is how much comparatively? Example if a lifted XJ loses quikness by lets say half a sec compared to the stock one. Would it then lose 6 seconds compared to the stock XJ in the montains of Colorado? I guess the primary point we are debating is that both the lifted XJ and the stock one would lose the same amount of performance with the hills and altitude. He is telling me that the lifted one would lose more power than the stock one. If they both lose by percentage then they both lose the same amount of power and performance right? Even if the difference of loss is greater with the lifted one it shouldn't be X2.

 

[YELLAHEEP]

Re: Driving in Colorado Question

I'm pursuaded to believe your friend - mostly because of the hp and torque curves and how the heavier tires/wheels and their rolling diameter affect that.

If the lifted XJ's engine is working harder at sea level compared to a stock XJ, then the power band is gonna be different. The same at altitude - however, the lack of oxygen affects the engine's performance and efficiency with the fuel, thus dropping the lifted XJ's ability to perform within the same power band curves as it did at sea level.

Think of it this way. You go hiking in your home town with a 50 lb back pack and you can go X distance before getting tired. You come to Colorado with the same pack and try to go the same distance.... you're gonna work that much harder, move that much slower because your body isn't getting the oxygen you're used to to perform at the sea level rate. Now change the weight in the pack to 80 lbs (we'll call that the same handicap as the lifted XJ has) and you're working even harder and slower.

Or think of being on a 10 speed bicycle. The deeper gears would simulate larger tires - you work harder at sea level, and have less power at altitude because of your inability to perform without the required oxygen.


Ya dig?

 

[Rob Patterson]

Re: Driving in Colorado Question

I can't give you exact numbers or anything but I can tell you that my XJ is way down on power after I moved from Florida. I have the 4.0L HO with a Borla header 35's and only 3.55 gears with the stock 5spd. In florida I could go 75-80mph very easily and I could get 20mpg if I kept it at 70mph on the highway.

Now that I live in Colorado Springs at 6000ft, I have a hard time staying at 75mph unless I'm going down hill. Any kind of uphill at all and I have to downshift to 4th. Just trying to maintain 70mph on the highway between here and Greeley; I can only average 15mpg. This is also with the addition of the better 99 style intake. I also had to step down from my ford 24# injectors once I got to Colorado because it was running way too rich. While I was in Florida, I was able to run the 24# injectors with no obvious problems and I still had a lot better gas mileage.

Rob

 

[HossHoffer]

Re: Driving in Colorado Question

IIRC power loss is 3% per 1000ft.

That's probably true except when you drive an old 1 bbl carb and then power loss is a squared function!

 

[jimgrms]

Re: Driving in Colorado Question

I have a stock cherokee except for 235 /16 tires a k&n air filter and flowmaster the quite one,, i notice no difference in preformance between colorado and down at sea level, I cruise while climbing I 70 going to utah it seems to shift more often so i just turn it off , It has been a good truck for me as its very dependable and is more economicle than the 2wd chevy short bed i owned,