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Gas Mileage

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Broke84, Aug 15, 2005.

  1. Broke84

    Broke84 Registered Member

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    Got a dilemma, hoping for some good advice. I'm getting rid of either the '02 Civic or my 84 K5. I love the truck and have put a lot of sweat and money into it and hate to get rid of it. But I did the math and the gas mileage and upkeep makes it about the same cost (if not more) as making a payment on the Honda. And the reality is, the Civic is a more reliable car, even though it's not nearly as fun.
    When I was driving it daily last year, I was burning through a 30 gal tank in a little over a week. I'm guessing below 10 mpg. Compared to almost 30 in the ricer, at $2.50 / gallon thats gonna hurt. So, convince me to keep the K5 please. Is there anything I can do to improve the mpg?
    It's a 350 carburated, on 33's, not sure of the gear. It's a 10 bolt with pretty low off-the-line power, so I would think it's stock. I know it's running rich - my wife used to complain that I smelled of gas when I drove it, so I guess a carb re-build is in order. Anything else? Thanks.
    Ken
    :confused:
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Why do you HAVE to get rid of one or the other?

    I assume by your comments that the truck you own. If that's the case, the truck is already paid for, why dump it? If there are other circumstances, what are they?

    In my case, I've got two non-daily drivers, one is a long term project, the other is the truck. The daily driver is the econobox that gets good mileage and is under warranty for a long time. (read, not me fixing it)

    Insurance is a killer for a lot of people, one great thing is "garage coverage" and of all the insurance companies I've dealt with, Farmers is the only one that offers it. In my case, the daily driver is insured full coverage, and the truck is under the garage policy. Essentially, you decide what kind of coverage you want on that vehicle, then pay something like $9 every six months. If you want/need to drive it, you call them up, tell them you want the coverage "activated" and they do. It's thus insured and ready to drive. When you are done, you tell them to de-activate the coverage, and they do.

    Then, they pro-rate your usage. Making up numbers here, say with the coverage you decided on for the truck, if you had the "normal" policy, it cost $600 for six months. Out of those six months under the garage policy, you only used it for one month. You'd pay $100 for that six month period. This is broken down DAILY though, so the cost could be very very little if you only use it for a few weekends.

    My driving record is perfect, but even with the perfect record, the savings from the garage policy are ENORMOUS compared to any other company/policy options.

    That is the biggest hassle to me in having multiple vehicles anyways, the cost for regular insurance on both was a killer. Now I'm paying around $360 for the two vehicles per 6 months.

    Another way to look at it is that if you really love these trucks, and you get rid of it, eventually you will want another one. Replacement cost is going to be more than you will get from selling it, and if you like YOUR truck, finding another you like just as much later on, may be near impossible. Besides, replacement cost is going to be more expensive than doing the upkeep required on any vehicle no less than 14 years old.
     
  3. muddybuddy

    muddybuddy 3/4 ton status

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    hey, where in VA are you?

    keep the truck man. find out what gears you got in that thing, gears will make a pretty big difference.

    u dont need the import, be patriotic :D
     
  4. Broke84

    Broke84 Registered Member

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    No, I don't have to get rid of one of them, but my wife has a reliable s-10 Blazer and I've got the 2 vehicles (one of which I'm making payments on.) I just figure, why put out that extra money for something I don't need. Insurance isn't really a factor either, I pay less than $20 monthly to insure it. The real issue is that I enjoy the truck and want to keep it, but 25 to 30 gallons a week X 2.50/gallon = up to $75 a week in gas. That times 4 plus insurance is more than the payment / insurance / gas in the Honda. If there are ways I can improve on the mileage, I'd like to know, maybe running a different gear, a different carb, etc. I know, if I want strictly gas mileage, I should keep the 4-banger. But I don't mind driving a V-8, just would like to get better than 10 mpg. Thanks.
     
  5. Broke84

    Broke84 Registered Member

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    I'm in Hampton. I'm putting tires on it this week. I'll see if I can't figure out the ratio then while I have it on a lift. It's axle rotations per wheel rotation right?
     
  6. muddybuddy

    muddybuddy 3/4 ton status

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    the number of times it takes the yoke to spin for the tires to complete 1 complete rotation. or you can take the dif cover off, change fluids and count teeth.
     
  7. Broke84

    Broke84 Registered Member

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    Thanks, I'll count rotations. Wish I would have thought of counting teeth a month ago when I changed diff fluid. :doah: So what is the preferred gear for a daily driver on 33's? Funny, on my Mustang, I went with 4.10's for the low end torque and lost mileage.
     
  8. muddybuddy

    muddybuddy 3/4 ton status

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    i think 410s would be good for 33s. you probably have 3.08 3.42 or 3.73. the gears will correct for the bigger tires, so you dont have to make the engine work as hard to move the extra weight. itll save the tranny as well, which is nice :D
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    The cost to do any sort of swap to increase mileage will take quite awhile to recoup, although with todays gas prices....

    Seriously, if you got 15-18 freeway, you'd be doing good. 10-13 in the city is going to be a good average as well. 6.2 diesel, you could probably increase that a fair amount depending on vehicle setup. Any sort of combined city/freeway is going to kill the overall MPG. Slowing down is about the single biggest thing most people need to do on the freeway to increase economy. Well, that and keeping constant throttle pressure, but I digress. Driving habits influence economy like you wouldn't believe.

    BUT, again, look at what it will take to get a vehicle to gain 5-8MPG. If the entire setup is in good working order in the first place, it's going to take a lot of money to make a vehicle even more efficient. You could easily spend over $2000 in fuel injection and trying to make an engine as efficient as possible, (roller stuff, better exhaust, heads, etc.) yet still gain only 2MPG.

    Of course, at 10MPG, (or less) somethings not right on a near-stock truck, at least a half ton. As long as that's actual MPG, (speedo is correct?) it should be pretty easy to gain 3-5MPG, perhaps more. FWIW with a 350/Q-jet/465/205/3.42's and 33's my best MPG was 18 on the freeway, 15-17 was easy to achieve. In town was always 10-13. In town mileage seems to be fairly similar whether you've got a 6 cylinder or 454 in these trucks.

    Carb rebuild kits are cheap, you think it's running rich as is, so see what you can do to solve that problem, and see where it gets you. Carb rebuild/fine tuning certainly can't hurt.
     
  10. mrjay40

    mrjay40 Registered Member

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    I'm with dyeager, 10 mpg is pretty low for a K-5, unless you are running in the mountains or drag racing on a regular basis.

    I was getting 10 to 13 in the city, but was running a high performance setup. To get some better economy, I did a tbi conversion (built my own system from available parts). It now gets 13-15 city without a loss of performance. With effort the tbi can be tuned to run much leaner but with a loss of performance.

    It still hurts to fill the gas tank but now I get double what a Ford Excursion can do and I'm faster and better off-road :haha:

    Jay.
     
  11. Broke84

    Broke84 Registered Member

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    10 is just an estimate, but I bet I'm not far off. That was last year before it went down w/ electric problems. Since then, I have changed the plugs and air filter. I've only driven it around the block, but it does seem to run a little better. We'll see. Maybe I'll go for new wires too, not sure if that would help much. I got very little info from the PO, so I've got to assume nothing had been done in the way of normal maintenance. I'm positive the carb needs work, like I said I reeked of gas when I drove it. Maybe a fuel filter change as well?
    With my last car, I got the gear done for about $300 w/ parts. Unfortunately the shop that did it is now closed. Anyone know a good place in Hampton Roads for gears?
    And no, I don't race it. It gets off the line like a Metro w/ a dead cyllinder, I'd look like a retard. Just normal, all in town driving - about 20 - 30 miles a day 5X a week.
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    All in town, gas engine, 10-13 is going to be all you will get for the most part.

    If you know things are wrong, fix them, but I don't see it getting much better than that.

    A real MPG figure will tell you where you are now though, and I wouldn't make any decisions until after you get any fuel problem solved, and a real MPG figure. When you are talking a difference in 1-2MPG, guessing isn't going to cut it.
     
  13. Broke84

    Broke84 Registered Member

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    True. Running 33's instead of 31's should make my speedo / odo off right? It will reflect higher speeds and mileage than actual? Or is it the other way around? Sorry to keep referencing my old car, but it's what I know...with those cars, there was a box called a speedcal that plugged into your tranny that you could program for your application. You just flipped dip switches based on tire size and gear ratio, then it would adjust your speedo / odometer. Is there anything like that for the K5's?
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    Ugh the speed calculations always make me think too much. :)

    With larger tires, transmission/t-case output shaft RPM's are lower for same MPH, which means speedo cable slows down, which results in lower speed than actual. That means the odometer slows down as well, and you actually go further than what your odometer says you have. I believe I've got that right.

    Only '90-91's can be modified the way you talk about, (electronic speedometers) although it requires soldering, same principle.

    Two ways to fix cable drive setups, change the speedometer gears, or get a ratio adapter. The adapters are fairly easy to find, but they come in a huge assortment of ratios. They can be purchased new as well, about the easiest way to fix a cable drive speedometer reading.
     
  15. zeroz400

    zeroz400 1/2 ton status

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    Seems like your only other option besides selling the k5 is just driving it only on weekends and for fun. Use the car for driving around and the truck whenever you feel like. Its gonna cost you money to get better gas mileage so you wont be gaining to much in the end.
     
  16. fatbob

    fatbob 1/2 ton status

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    Don't go with 4.10's if you want better mileage. My 77 K20 got 10-11 MPG
    with 4.10's and 33" tires. But my 80 K5 got 14-15 MPG with 2.73;s and 33" tires.
    4.10's = better preformance
    2.73's = better mileage
    But you admit it not running right, so get the [ I reeked of gas] problem fixed first, and then worry about tires & gearing.
     
  17. Broke84

    Broke84 Registered Member

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    OK, now I'm confused. First of all, it was nice to finally get the truck back on the road. I put it on a lift to put new tires on and checked my gear while it was up. Now, I know with 33's it will be a little off, but should be close right? I did it several times to make sure I wasn't crazy, but with one wheel revolution, the yoke spun about 1.75 times. Is there even a gear that low for these trucks? Just for reference, it doesn't pull very hard, but is extremely short in the first 2 gears. Sometimes, I don't even use 1st because the rpms shoot up so fast. That sounds like my old 4.10's, but definately without the torque. So whats with the < 2 revolutions per wheel rev? Any ideas?
    As a side note, I decided I love the truck too much to get rid of. I'm keeping it, selling the Honda and buying a no-payment beater for DD.
    :saweet:
     
  18. RubberFloorMat

    RubberFloorMat 1/2 ton status Premium Member

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    so i must be the only one in the word that gets 15 city and 20 hiway in a K5?????


    seriously, i have a 91 with tbi and a 700r4 with 3:08's and i get pretty damn good milage..


    anyone else get good milage??
     
  19. Thunder

    Thunder 3/4 ton status

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    Close. I get 18 hiway at 75-80 mph 14-15 city. I can get 20 mpg but I cant stand to drive 60. Its so sloooooooow.
    I use 89 octaine. 89 K5, 350 TBI ,3.73 GR, 33" MTs

    Matter of fact I just did a major tune up on my k5 and ran a tank out. Cost me $60 to fill up. :eek1: It took a little over 22 gallons to go 365 miles. Thats better than 16 MPG average for both city and highway plus a couple of short trips off road to do some shooting and pick up a load of rocks. But I have been driving it real easy since gas went up :doah: . Gotta love fuel injection.:thumb:
    LOL :D with gas at 2.80 a galon I guess 60 mph aint sounding so slow any more.
     
  20. eddy

    eddy Newbie

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    get a propane tank set up in your blazer and run your truck on propane.its about a $1.60 a gl where im at, and u will get alot better mileage.
     

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