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turbo fuel mileage

Discussion in '1982-Present GM Diesel' started by blaz_mem, Oct 15, 2005.

  1. blaz_mem

    blaz_mem Registered Member

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    Im in the process of posting pictures. But my fuel mileage for a turboed 6.2 with 35's 700R and 4.10's is 17.22 mpg
     
  2. k5blazin

    k5blazin 1/2 ton status

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    Is this with using the Banks Sidewinder kit or a custom kit??
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Sounds low to me...is that city or highway or mixed?

    My Jimmy, 6.2/SM465, 4.56's and 39.5's gets 16.5 on the highway and it's spinning at 2550 rpm. Your combo should be spinning at 1800 which is damn near the peak fuel efficiency range...plus you're on smaller radials (I'm assuming your 35's are radials)

    Maybe it's just me, but I'd expect that combo to net over 20 mpg on the highway.

    Rene
     
  4. imiceman44

    imiceman44 1 ton status

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    You are forgetting one major component, what is the average speed of most of your driving?
    If you run 1800 you get speed limit maybe he is running faster.
    Highway miles with diesels are like in town miles for a gasser, you burn more fuel :haha:
    Mine drops drastically from 30 MPG in town to 20MPG on highway. :mad:
    IceMan
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    My highway mileage is better than my city mileage.

    I don't often drive faster than 65-70, so i use that as a 'baseline'.

    Rene
     
  6. arveetek

    arveetek 1/2 ton status

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    My '81 turbo with the hot rod 6.2L is only giving me 15 mpg. I'm rather disappointed...but I guess that's what you get for increasing fuel delivery and making a power house. It tows like you can't believe now, though! :D

    Before turbo and other engine mods I was getting a consistent 18.5 mpg.

    I haven't had the '95 long enough to record mpg yet. I'm hoping for near 20 mpg....seems to be going a long way on a tank of fuel.

    Casey
     
  7. blaz_mem

    blaz_mem Registered Member

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    I think I have my fuel pump turned up to much. But another problem I have is Im not getting much boost, but it has alot of power and smokes like crazy. It is a gm3 off of a 6.5 with straight 3 inch pipe all the way back into a 3 1/2" pipe and a 4" turndown. When the mileage was checked for the first time it was mostly highway miles about 55-65. I have the wastegate tied shut so I should be getting max boost unless my gauge is in the wrong place. Also I had a left rear shock mount break away from the frame is there any other place to mount the shock? I am thinking of mounting it straight on the frame
     
  8. arveetek

    arveetek 1/2 ton status

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    How much boost are you seeing? On a 6.2L with a GM-3, I would think you ought to see in the neighborhood of 10-12 psi. Low boost will increase smoke. Perhaps you have a leak in the pressure system. Are you sure the wastegate is tied shut and not tied open? As long as the boost guage is tapped into the intake system somewhere after the turbo, the readings should be correct.

    Casey
     
  9. blaz_mem

    blaz_mem Registered Member

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    Well I know its the tied down the right way because when I did it the other way, I couldnt hear the turbo spool up and it was real sluggish. I only get about 3-5 psi when I really stomp it and the rpms get real high. I think I have a leak in my intake tube cause I kind of rigged it to make it work.
     

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