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Climbing Colorado Passes

dodo4bird

NAXJA Forum User
Location
colorado
I have a 91 XJ with a 4" lift and 32" tires. The XJ is a manual with 278K on it. I am constantly driving over Vail pass/ Loveland pass in Colorado. My XJ will go 65mph up the pass in 3rd gear. I am replacing my jeep with a 1999 or newer XJ, but am switching to an automatic. My question is will I be lacking the power in a 99 or newer automatic to climb at that speed? (There is a 4” with 32” on the new jeep as well) Also read that throttle bodies can add some HP!! Can I get some opinions?
 
thottle bodies do not add horsepower, they tend to add throttle responce, which is not what you are looking for. Or I should say that they do not add noticable Horsepower, and especially not to a stock motor.

You can get a minimal gain from the TB upgrade, but I would do it yourself or have a machine shop do it. Not worth the price that most places search.

Geared right you will not have a problem, but you may end up making the shifter unit that allows you to chose the gear you are in and if the TC in locked.
 
Here's some real life experience for you. 2 years ago, I went out to Colorado with my stroked XJ for some skiing. The thinner air definitely saps some power from the engine. On I70 west of Denver, I got ballsy and decided to floor it up on of the passes. Before I knew it, I was doing over 100 going up a 5 or 6% grade. My sister was following me in her Lumina, and I watched her get smaller in the rear view mirror.:looney:

Granted, I don't have a lift or oversized tires, but it is possible to have an XJ perform well in the mountains. If you had a stroker and 4.10 gears, I think you'd have all the power you could ever want. Heck, just gears with the 4.0L would probably be sufficient.

Wolfpackjeeper-
I just noticed you're from the "taint" of florida. That makes me laugh. I assume you're familiar with what a "taint" is, correct?
 
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If it hasnt been done, I would say proper gearing should be more of a concern than engine power. No matter how much power you have, running too tall of gears is going to make it feel like a dog. Granted, you are loosing something like 30% of your power on top of vail pass vs. sea level. If your gears are good, id then look into less restrictive intake/ exhaust, maybe a cam, or if your really looking for something, a stroker with all of the above.
My 99 stroker manual has stock gears and 31's.. It has plenty of power, but with the gearing off, it makes I70 a bit of a challenge. I can cruise most of I70 in 4th or 5th, but on the bigger hills the rpms drop too low, and I can only hold about 60-65. If I drop to 3rd, I can do 85-90 up any hill no problem, but the rpms are up there.
 
Wolfpackjeeper-
I just noticed you're from the "taint" of florida. That makes me laugh. I assume you're familiar with what a "taint" is, correct?

Yes, I live in Pensacola right now. So if you look at a map of the southeast and look at a picture of male gentalia, perhaps superimpose the two you can see where it comes from.

A couple of people on here live in the "dong" portion of the state.
 
He didn't ask about a stroker or new gears, how do you guys get so off-topic so fast?



I have a 2000 myself, with an RE3.5" and 32x11.5 MTR's. I had a 90' with an RE3.5" and 32x11.5 BF MT's. Both autos. The 2K has 210,000KM, and still has plenty of power for everywhere I drive it. Hills it's fine with, its wind it doesn't like.
 
I have a 99 4.0 and automatic and I can usually get the ol' girl up to 70-75 with my foot to the floor and gear selector in "D" or "3" up I-70 out of Denver/Golden. I have a 2" lift with 30"s and a very heavy winch/bumper combo on my front end.

I can squeeze about 80 out of it if I throw the gear selector in the "1-2" position and hold the rpms just below the 5300 rpm fuel cut off/rev limiter.

Once I get up really high around the Eisenhower Tunnel it won't do more than about 60-65 no matter what I do. Of course getting stuck behind a semi in granny low, or a Kia doesn't help the Jeep get back up to speed either....
 
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I think gears and a stroker are about as on-topic as it gets here... If you want a Jeep with bigger tires to go *anywhere* in a timely fashion, one of those two is necessary. The 4.0 is a fine engine but there are no miracles being pulled from it... without a 258 crank
 
Yes, I live in Pensacola right now. So if you look at a map of the southeast and look at a picture of male gentalia, perhaps superimpose the two you can see where it comes from.

A couple of people on here live in the "dong" portion of the state.


Oof. So far BFE, Mobile Alabama is a cultural meca.

My mothers in Pens. I try not to visit. :)
 
Thanks for all the input. I will put a lift on and see how it does. If I think it needs some power then I will look at gears for it. and hopefully a bumper and a winch will add the weight to force me to do gears.
 
I have a 91 XJ with a 4" lift and 32" tires. The XJ is a manual with 278K on it. I am constantly driving over Vail pass/ Loveland pass in Colorado. My XJ will go 65mph up the pass in 3rd gear. I am replacing my jeep with a 1999 or newer XJ, but am switching to an automatic. My question is will I be lacking the power in a 99 or newer automatic to climb at that speed? (There is a 4” with 32” on the new jeep as well) Also read that throttle bodies can add some HP!! Can I get some opinions?

I have a 98', with an automatic, 31" tires, and 4.5" lift. The thing I notice about the higher passes is that there is a variety of speeds going over the passes from Semi-Trucks, to cars playing like they are on the Autobaun.

Going faster up a steep grade wastes fuel and puts heat in the transmission/cooling system. Buy a tranny cooler to assist in dumping some of that heat. Keep the machine in 3rd (not "D") as you do with your 91'. The 99' already has more power, and lower gears than the 91', so you will already see a performace upgrade over your older XJ. If you want bettter performance than that, regear.

Don't worry about going fast. A lifted XJ is not a sports car.
 
I have a 91 XJ with a 4" lift and 32" tires. The XJ is a manual with 278K on it. I am constantly driving over Vail pass/ Loveland pass in Colorado. My XJ will go 65mph up the pass in 3rd gear. I am replacing my jeep with a 1999 or newer XJ, but am switching to an automatic. My question is will I be lacking the power in a 99 or newer automatic to climb at that speed? (There is a 4” with 32” on the new jeep as well) Also read that throttle bodies can add some HP!! Can I get some opinions?

Knowing the area and what altitude does to power ouput (thinner air makes thinner HP :)), I wouldn't run anything less than 4:56 gears with 32" tires and an auto......and I'd think really hard about 4:88s', especially if you think that a 33 or 285/16 tire is in your future.

I live on the Wasatch Range in Utah and don't spend alot of time at the Vail-ish altitudes, but when I run up the canyons to 8k elevation to go snowboarding, I'm really happy to have 4:88's, and I commute in my 2000 XJ too, very happy with this gearing (auto, 231Tcase, 33" tires, 6" lift)
 
It is not that bad of a place, just not great. I like the joke portion more than anything else. There are def worse places to be stationed.


True, it wasn't as bad as Macon. My mother and stepfather ended up retiring there, and live out in the hinterlands now (Holt) on a pretty good sized horse property.

The first time I came to visit, I went looking for milk for my coffee in the morning - it was a 30 minute drive. each way.
 
i live in colorado and run up those passes alot , i have a 98 xj with the 99 intake a 60 mm tb a short ram intake and flowmaster cat back exhaust and a gibson header with and auto and on 31" tires and 3.55s it did ok up there i had to push it a little on a few of the hills but i can usually hold about 60-65 all the way up and the only thing i have had a problem with is that it will run really hot if you keep pushing it hard so power isnt everything you may need to look into some cooling upgrades. my jeep is now on 33s and 5.5" of lift and still 3.55s and its a dog going up. so cooling and proper gearing should be your biggest concern
 
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