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would it make it to (and from) moab?

Discussion in 'The Garage' started by vortec, Jan 22, 2007.

  1. vortec

    vortec 1/2 ton status

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    my friend has been hounding me, for years, to go to moab. his jeep, my '82 k5. gas cost is the first thing that keeps me away. it's over 1000 miles each way, and then there's the gas spent on the trail. just too dang much $$$. and, while i'm no expert on carbs, i'm pretty certain that going from 500 feet or so here in dfw, to 4000+ in moab, would really mess with the old quadrajet. it runs rich enough, anyway, once the temps get above 85 or so, here (so most of the year, in other words) have any of you guys from low elevations made that type of trip without rejetting or swapping carbs on the way?

    my friend would be taking his 2006 rubicon, this time, but the last time he went, he took his '90 jeep with open difs. one dana 30 and one 35, i think. so, i guess my stock k5 with open 10-bolts (run 'em till i shatter 'em) MIGHT hold up and get me through. i would probably have 33x12.5x15 tires by then. rolling on puny 31x10.5s right now. they get the job done, but sides have seen better days. rock rash, etc.

    i guess i'm just feeling a bit insecure about my (budget) rig, in this case. :o . i've actually been looking at zr2s and tacos, off and on, for the last few years, to get better mpg, even if the stock offroad capability isn't quite as good. i'd keep the k5, just not as a road-trip rig.

    advice?
     
  2. 1977k5

    1977k5 3/4 ton status Vendor

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    Don't forget that you would be driving over the passes in the rockies. Assuming you take I-70, you will be as high as 11-12K feet. If you don't change your mixture you'd be lucky if your truck made it to the top of the passes at all, albeit at 25 MPH and puking black smoke.

    If you want to make this trip, grab a set of leaner jets (~64-66) and swap them in at some point along the way in southern Colorado. Its easy and pretty quick. You may also need to change the metering rods (about 30 seconds more work if you are already changing jets).

    Only you can decide if the cost is worth it. Moab is like no place else on earth and I'm sure you wouldn't regret it if you made the trip :D
     
  3. bp71k5

    bp71k5 3/4 ton status Premium Member

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    I'm at about sea-level over here and I drove my carb'd k5 to moab in October. ~1200 miles each way. No problems at all related to that. I guess if you're crawling over really steep terrain you might get into some issues, but nothing you're going to get into in a stock blazer would qualify. Even gas costs wasn't that bad. (~$500)

    Here's me going up a pretty steep incline (baby lyons back) which isn't a big deal for experienced wheelers, but is probably a 30+ degree incline at least. (the camera is level) I'm running 33's and open diffs on both ends. you can see my wheels spinning on the rock. No motor problems except the radiator overheated on the way down.

    http://www.youtube.com/watch?v=_BW4sXAESAA

    I think you'll be fine.
     
  4. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    I have to go through 7000+ FT elevation in Northern AZ to get to Moab . Home is less than 1300 FT elevation roughly . BB07 I didn't bother to mess with my Quadrajet :thumb:

    Gas is easier , you have multiples of months to do a little saving here and there . A 20 each payday in a jar would work :waytogo:
     
  5. Brians89K5

    Brians89K5 1/2 ton status

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    I used to drive to flagstaff all the time from Needles california. It was like +4 from sea level to +7000 above. Somewhere along the way I would hop out and advance the timing a bit and my truck ran like a champ. No biggie there.

    ~Brian
     
  6. vortec

    vortec 1/2 ton status

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    yeah, i forgot about the extreme height of some of the mountain passes. i have relatives in crested butte, and my obd1 tbi pickup does fine, up there at 12k feet, but with significant power loss. i, like many people on the boards, find the quadrajet a bit intimidating, especially since i haven't worked on simpler carbs much, either. but, if rejetting is really that simple on it, that may be the way to go. i'll try to read up on it and get more comfortable.

    as far as the inclines go, i agree i'd be fine. i've taken steeper (albeit, for shorter distances) out at BMRA, in east texas, without stalling. i know we've all seen the infamous video of the k5 flying down the lion's back and smashing into the ground. i don't want to make another vid like that.
     
  7. Chrisblazzer89

    Chrisblazzer89 1/2 ton status

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    I have a stock TBI 88 :k5: . would I have to do anything to it for me to make the trip?
     
  8. 1977k5

    1977k5 3/4 ton status Vendor

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    Nope
     
  9. 1977k5

    1977k5 3/4 ton status Vendor

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    Changing jets on a Q-jet is easier than many people make it sound. If you change jets more than a couple sizes you should probably change the metering rods too.
     
  10. Chrisblazzer89

    Chrisblazzer89 1/2 ton status

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    So the elevation change Thur the whole trip wont effect my TBI?
     
  11. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    Thats what the computer , and the sensors are for . Your truck will adjust itself .
     
  12. Chrisblazzer89

    Chrisblazzer89 1/2 ton status

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    Thanx. I didn't know that and now I do.
     
  13. Leper

    Leper 1/2 ton status

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    I will be at Blazer bash this year. I am looking at several possibilities to get my truck there and back. I am pretty sure I will be breaking something so I won't be driving it. If I can find a hauler going that way anyway, do you want me to save you a spot.

    A little heads up...... In my research on this I have found some good ideas. If you can be without your truck for a little while, you can find a truck that is going up there empty(a return trip or something). You can send your truck to someone you trust a month or so before you go, the same goes for the return trip. It may be there a few weeks before it comes home to you. A driver that is going that way anyway will haul your truck for a few hundred bucks. Don't trust just anyone.
    That is what I'm doing right now, looking for someone that is going that way. It will be later in the year before I can get a confirmed date, but that is how I'm getting my truck from Tx to Moab and back.
    .02
     
  14. HarryH3

    HarryH3 1 ton status Author

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    The one thing that you WILL notice, is the loss in power as the altitude increases. But this has nothing to do with fuel delivery. It's all about atmospheric pressure. That is what fills the cylinders on the intake stroke. It gets lower as altitude increases, so less air gets into the cylinders. The TBI will adjust the fuel delivery lower to keep the mixture correct, but the lower chamber pressures have a huge impact on power. You'll be amazed at just how gutless your V8 will be when climbing those 6% grades on I-70 between Denver and Vail. :shocked:
     
  15. jms

    jms 1/2 ton status Author

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    Coming from Texas, it might be better to stay on I-40 and then take US666 (or whatever that highway number is these days) up north thru the Navajo rez. No 11-12k Eisenhower or Vail Pass to conquer; highest might be below 8k near Monticello, UT.

    I've made the trek to Moab from Nebraska numerous times, and yes, the passes in the Rockies take the stuffing outta the truck :D - I'm usually down to second gear a quarter mile before the tunnel going west...:( . Now, from a standpoint of general maintenance, and considering the fact that my truck is a true dual-purpose vehicle (Highway as well as trails) my line of thinking is that if the truck doesn't survive the drive on the highway, how is it going to survive the trails in Moab? Then again, I've always looked at the drive to Moab as part of the whole adventure, and I actually enjoy driving across the country, rather than just looking at it as transportation to an event.
     
  16. vortec

    vortec 1/2 ton status

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    harry is right. since the high altitude air is less dense, less molecules of oxygen are delivered in the same volume of air, compared to lower elevation. the o2 sensor detects a shortage of O2, and backs fuel delivery off accordingly, to maintain the air/fuel ratio at a near-stoichiometric point. that's 14.7:1 with pure gas, but in real-world conditions, the gas has moisture, oxygenation agents (like ethanol), and other stuff, and the required ratio is lower. 13:1 or 14:1, for example. the goal is to provide enough oxygen to completely burn the fuel in the cylinder, instead of dumping raw fuel out the tailpipe, but not so much o2 (lean condition) that preignition occurs. the process is never perfect, since the sensor and therefore, the computer, can only react to what has already happened. i run an air/fuel ratio gauge on my '94, which simply taps into the signal wire of the o2 sensor. under normal closed loop operation, it quickly cycles between slightly lean and slightly rich, as the computer makes adjustments in fuel delivery, based on the latest info from the sensor. an obd2 system makes these adjustments much quicker, and also uses about 8 billion sensors instead of one. ok, maybe not that many. the gauge isn't necessary by any means, but it can give you a clue about problems, if it starts acting strangely. and, it makes for a nice lightshow, at night:wink1:
     
  17. SHAWNSTER

    SHAWNSTER 1/2 ton status

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    back in 99 i drove my 92 s-10 4x4 through nm and into colorado, and my s-10 would not go over 10-15 miles per hour with my foot to the floor, i thought my blaze was breaking down, and my bud said when we pass the mountains it will go away, and it did, but I always wondered if it was the altitude or my blazer
     
  18. enigma2y0u

    enigma2y0u Registered Member

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    I live at 7500 feet and lived for the last couple years at about 700 feet. I can't imagine you would have any problems what so ever. There is a HP change, but that is due to elevation in general.
     
  19. vortec

    vortec 1/2 ton status

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    99? dang, that obd2 system should have been able to compensate pretty well, considering the fact that my 94 obd1 did. maybe it's just the fact that they choke off the airflow on s-10s compared to the 4.3 in a fullsize. my mom has a 2000 blazer and my friend has a 2001 s-10 pickup with (4.3), and it just doesn't look like those engines can breathe. the intake snorkels appear restrictive and the exhaust is much smaller than mine. not sure why they think my full-size needs 350 plumbing, but the same displacement engine in an s-10 can use drinking straws on both ends.
     

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