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Gas milage change

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by strukie66, May 25, 2003.

  1. strukie66

    strukie66 Registered Member

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    Hi i am new to this site but i have a 88 k5 with the tbi350 with the th400 tranny. i just bought it and it's getting a rebuilt tranny now it has 31's but other than that everything is stock what sort of gas mileage will i get and if i upgrade to 33's or 34's with a lift what am i looking at for gas mileage i am a college student that is not rich /forums/images/graemlins/rolleyes.gif
     
  2. sled_dog

    sled_dog 1 ton status

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    it has a th400? Guy before you was nice and smart since thats not factory. Though TH400 isn't best for fuel mileage since it doesn't have overdrive. Need to find out what gears you have. THat will determine how much of a dog the rig is with teh bigger tires and a bit of your fuel mileage. As far as exact numbers tehre is no way anyone can really say, depends on a lot of variables. Also no one really sells a size 34" tire.
     
  3. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    Figure out what gearing you have, then you can go from there with what tires to go with. You can use www.4lo.com to see about ratios and other stuff to give you an idea... oh, and if you are worried about MPG, then bad choice to buy one of those! These trucks are not know for being cheap at the pump... /forums/images/graemlins/grin.gif
     
  4. 87BrnRsd

    87BrnRsd 1/2 ton status

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    [ QUOTE ]
    Also no one really sells a size 34" tire.

    [/ QUOTE ]
    I think super swamper sells "odd" sized tires like 32's or 34's and others with odd widths as well. /forums/images/graemlins/wink.gif
    -Harrison
     
  5. 84_Chevy_K10

    84_Chevy_K10 Banned

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    32s are not an odd size. Nearly everybody makes a 32x11.50 tire.

    34s on the other hand, I only know of one.
     
  6. MousePowrd

    MousePowrd 1/2 ton status

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    If you can knock down 12-13 around town consider yourself lucky
     
  7. strukie66

    strukie66 Registered Member

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    i am getting super swamper ltbs... yea i know it isn't factory( the TH400). thanks for telling me about the 12-13... o about the wrong for buying a k5 hehe i love blazers and was just curious about the gas milage. the gearing is low(2.48:1) dude this forum is great considering everyone writes you back
     
  8. ChevyCaGal

    ChevyCaGal 3/4 ton status

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    What gearing are in the axles though....
     
  9. bryguy00b

    bryguy00b 3/4 ton status

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    inless you have atleast 3:73 gears i wouldnt go over 33's
     
  10. jwduke

    jwduke 1/2 ton status

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    Sorry, but I hate to tell you this, but this "hobby", gas milage is going to be a thing of the past, for the most part! So either enjoy the looks & the offroad mobility you have, or stay out, and wish you would have done it. You take a K5, with 1T axles, loaded with 5.13 gears, and a set of 44" tall rubber. 8-10 mpg, on the road might be a "pipe dream" Welcome & good luck in your new "hobby"!
     
  11. strukie66

    strukie66 Registered Member

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  12. ajalecci

    ajalecci Newbie

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    I just bought a Jimmy. On the drive home from NJ I got about 13-14 on the Highway. I tuned it up, fixed some broke items, and put 4.56's in it and I still get 13-14 on the highway. I am running 33's.
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Well, obviously since your other post has to do with the speedometer being off, your mileage accuracy is way off as well, regardless if its the same before/after the gear change.
     
  14. Poohbair

    Poohbair 1/2 ton status

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    On my trip to Naches last weekend I figured that I got about 9 on the highway getting there. That was running a carbed 350, 4spd, 4.10's, and 38's
     
  15. gravdigr

    gravdigr 1/2 ton status

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    ooh I can't wait to see what mine gets with 35s and 2.76 gears /forums/images/graemlins/laugh.gif seriously I prolly will run the crappy lt235s I have until I get 1ton axles installed with at least 4.10s
     
  16. 87sm465np208

    87sm465np208 1/2 ton status

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    ouch 2.76 and 35's that might put alot of stress on a area that dosnt like alot of stress, the tranny.

    /forums/images/graemlins/usaflag.gif /forums/images/graemlins/truck.gif
     
  17. Blazer_Boy

    Blazer_Boy 1/2 ton status

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    Wanna know what gears, eh? Jack the truck up, block one wheel and jack the other off the ground. Place the tranny in neutral and head on over to that back tire off the ground. What you do is turn that wheel around a complete revolution and watch the yoke on the differntial. Count the number of turns and multiple by two. If she turned 1 1/2 times, then that multiplied by 2 would get you 3. Which would be 3.08 gears. You're likely gonna be stuck with, 3.08, 3.23, 3.42. 3.73 (rare) in that vintage Blazer. Just pray to God you don't have 2.73s. 4.11s would be about perfect for you. Those are pretty common gears in 3/4 trucks. That would be a good swap, more strengh and gears.

    I just put 3.73s in my 2wd with 235/75/r15s and it really hauls.
     
  18. gravdigr

    gravdigr 1/2 ton status

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    "Just pray to God you don't have 2.73s."

    god doesn't listen to me /forums/images/graemlins/confused.gif
     
  19. ajalecci

    ajalecci Newbie

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    If I had used the readings from my speedo then yes, they would have been way off. But, lucky for us, they were from a GPS.
     

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