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lift vs mpg ...

Discussion in 'The Garage' started by rcurrier44, Jun 2, 2004.

  1. rcurrier44

    rcurrier44 1/2 ton status

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    Yes I have been searching.

    Its obvious that the higher you lift a rig the more aero-drag you are going to get. But how much of an effect is it realy. With rising gas prices this has become a consern of mine.

    I am thinking about doing a 3"-4" lift on my DD. There are some trails that I don't need (or want) to bring my big wheeling rig on. Currently my DD is a 76 1/2 ton chevy with a 350/th350/203, 3.73gears, 34x10.5's and a stock suspension. I would like to get some more uptravil (currently only 1.75") in the front and more flex out of the suspension. I get about 10mpg city and 13mpg highway; witch I consider respectable.

    So, has anyone lifted their truck without changing gearing/tiresize/engine and kept track of their MPG?

    Thanks
    ROB
     
  2. kennyw

    kennyw N9PHW Premium Member

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    If you are not going to increase the tire size you would probably only need to put on a 2 or 2.5" lift to get decent flex (depending on what springs/shocks you choose). I dont think the lift alone will change your gas mileage too much compared to changing to wider tires.
     
  3. rcurrier44

    rcurrier44 1/2 ton status

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    The reason I said 3-4" is because I would be using a set of modified 52" rear springs. They are terably saged after being in a 79 suburban all their life, but not bent. I am planning on pulling the overload and adding 1 short and 1 long leaf to the pack.

    I do have an add-a-leaf/stock front 2.5" pack around but don't like how stiff the ride is.

    One of the goals of this rig is to keep it as cheep as posible...I currently have just under 300$ cash-outlay in the hole truck /forums/images/graemlins/grin.gif I realy enjoy rubbing that in my Ford buddys faces, and want to keep this as low buck as posible. /forums/images/graemlins/thumb.gif
     
  4. kennyw

    kennyw N9PHW Premium Member

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    Well, since you already have the springs, just throw them in and recheck your mpg. If you can live with it keep it, if not return it to stock. Not like the mod will cost anything but a little time at this point /forums/images/graemlins/thumb.gif
     
  5. rcurrier44

    rcurrier44 1/2 ton status

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    Good point, I have a set of 2.5" blocks I could throw in the back for now (shackle flip later) to level it. I could also get away with the push/pull steering for now also.

    I was just hoping someone might have some first hand experience.
     
  6. MilpitasK5

    MilpitasK5 1/2 ton status

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    With trucks like ours, you just have to bite the bullet about the gas mileage man.
    Just can't think about anymore. /forums/images/graemlins/deal.gif
     
  7. smokkey1

    smokkey1 1/2 ton status

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    [ QUOTE ]
    With trucks like ours, you just have to bite the bullet about the gas mileage man.
    Just can't think about anymore. /forums/images/graemlins/deal.gif

    [/ QUOTE ]


    I hear that...
     
  8. blasterD

    blasterD 1/2 ton status

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    I didn't see much difference when I lifted my 78 4" and put 35s on, but when I went from 3.73 to 4.09 and from 4 to 6" I saw a pretty big difference.
     
  9. rcurrier44

    rcurrier44 1/2 ton status

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    Thanks, thats exactly the kinda info I was looking for.
     
  10. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    Yes I have been searching.

    Its obvious that the higher you lift a rig the more aero-drag you are going to get. But how much of an effect is it realy. With rising gas prices this has become a consern of mine.

    I am thinking about doing a 3"-4" lift on my DD. There are some trails that I don't need (or want) to bring my big wheeling rig on. Currently my DD is a 76 1/2 ton chevy with a 350/th350/203, 3.73gears, 34x10.5's and a stock suspension. I would like to get some more uptravil (currently only 1.75") in the front and more flex out of the suspension. I get about 10mpg city and 13mpg highway; witch I consider respectable.

    So, has anyone lifted their truck without changing gearing/tiresize/engine and kept track of their MPG?

    Thanks
    ROB

    [/ QUOTE ]Do you plan on keeping the same 34" tires? Gear ratios effect MPG more than the lift IMHO. First off 10 & 13 is EXCELLENT for a carbed rig with a th350. I doubt you would lose much with the same rubber and only 3-4" taller. If you do go bigger tires than that is where you will see a big difference. /forums/images/graemlins/waytogo.gif
     
  11. Blue85

    Blue85 Troll Premium Member

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    The gearing and choice of wheels/tires will have more effect than a few inches of lift.
     
  12. rcurrier44

    rcurrier44 1/2 ton status

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    [ QUOTE ]
    Do you plan on keeping the same 34" tires? Gear ratios effect MPG more than the lift IMHO. First off 10 & 13 is EXCELLENT for a carbed rig with a th350. I doubt you would lose much with the same rubber and only 3-4" taller. If you do go bigger tires than that is where you will see a big difference. /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    Yep I am keeping the same tires. I may eventualy go to a 33x12.5 but I will also be changing to a manual transmission by that time.

    I thought 10-13 was about normal. My old 79 blazer was getting 16mpg highway at sealevel with a 350/th350/203, 36x14 tires, a 7" lift and 3.75 gears. But I also ran the tires at 45psi and the engine was much stronger than this one.
     
  13. jekbrown

    jekbrown I am CK5 Premium Member GMOTM Winner Author

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    dumb question: why lift the DD at all?

    j
     
  14. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    Id say 10-13 is good now. When my truck was stock it got about 8 mpg around town, gotta be the cam. With the lift and all (14"), I get 12 on the freeway, hopefully even better with the TPI! /forums/images/graemlins/peace.gif
     
  15. 4xcrazy

    4xcrazy 3/4 ton status

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    I saw a big difference with my lift mainly on highway driving, i have driven a few times from Phoenix to SoCal area before the lift and after the lift and about the same size tires, just in 16" measurements, i have used quite abit more fuel, also the wind drag and "movement" of the truck is quite abit more noticable at highway speeds.

    I don't think people really pay much attention to these little details after they lift their trucks, because they know something is going to change and just get used to the change, but fuel mileage DEFINATELY changes for the worse when they are lifted, like you say, more areodrag, more wind under the vehicle is bad for the mileage.
     
  16. 84_Chevy_K10

    84_Chevy_K10 Banned

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    It really depends if you have overdrive or not. Non overdriven rigs generally have enough power that they never feel the difference.

    Overdriven rigs it makes a tremendous difference even going from 2-4" made a huge difference on mine when it had overdrive.

    Going from 4" with overdrive to 9" without overdrive netted minimal difference compared to previously going from 2" to 4" while having overdrive.
     
  17. rcurrier44

    rcurrier44 1/2 ton status

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    [ QUOTE ]
    dumb question: why lift the DD at all?

    j

    [/ QUOTE ]

    Cuz I can't leave good enough alone. /forums/images/graemlins/whistling.gif I am realy just looking for a little more uptravil in the front. Some more flex would be nice too. I would like to keep this one as a work/hunting/mild wheeler only and get a AWD car as a DD; but I already have 5 vehicles myself (not including the line of parts rigs) girlfriend has 2 more. I am realy fighting the urge to get another.
     
  18. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    [ QUOTE ]
    Do you plan on keeping the same 34" tires? Gear ratios effect MPG more than the lift IMHO. First off 10 & 13 is EXCELLENT for a carbed rig with a th350. I doubt you would lose much with the same rubber and only 3-4" taller. If you do go bigger tires than that is where you will see a big difference. /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    Yep I am keeping the same tires. I may eventualy go to a 33x12.5 but I will also be changing to a manual transmission by that time.

    I thought 10-13 was about normal. My old 79 blazer was getting 16mpg highway at sealevel with a 350/th350/203, 36x14 tires, a 7" lift and 3.75 gears. But I also ran the tires at 45psi and the engine was much stronger than this one.

    [/ QUOTE ] I mean this in no offense but are you shure you are getting the MPG numbers right? It is fairly easy to get off by a few miles or have an extra gallon in there or something. Remember that the odometer is not correct anymore(along with the speedo) when you go with bigger tires. Reason why I ask is because 16 is EXTREMELY good for a carbed truck with that much lift, gears, and tires. Most TPI rigs have a hard time getting that with optimal gearing/tire conditions. I get around 10-12 on the highway with a th700R4 behind my built 406 , although I am running 10" of lift and bias tires. /forums/images/graemlins/thinking.gif, and about 9mpg in town.

    Like I said, gears and tires are going to make the biggest difference, 3-4" of lift would make almost no difference in town and minimal on the highway. With the 33's you want I would run a 4.10 ratio, good MPG vs. performance.
     

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