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Gas Milage... no this isn't the same ole whiner post

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by CaptCrunch, Nov 6, 2001.

  1. CaptCrunch

    CaptCrunch 1/2 ton status

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    Gas Milage... no this isn\'t the same ole whiner post

    As I said in the title... this isn't a whiner post about how our trucks only get such and such miles a gallon and how can I spend $500 to .3 mpg more.

    Mostly I'm kind of curious what guys with modified TBI setups (chips, injectors, TBI units, etc) are getting. How bout TPI setups?Also any results of BBC's and 383's would be appriciated. Basically I guess the idea is to see what is getting what. Kinda thought it would be an interesting post with all the engine buildups being discussed right now, especially because a lot seem to be daily drivers as well as offroaders. I know what theorys and such all say... looking for some real world results.

    *For the sake of making results easier (if there is such a thing) try and give a complete infor of you buildup along with items like tire size, gears, amount of lift, etc.*

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  2. k5blazerus

    k5blazerus 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    well I have a 307 bored .40 over and a 350 crank in it, a slight cam, stock heads a highrise manifold and a 650 holley and IT gets maybe 10 mpg it sucks it down big time. It used to be driven every day but know just the weekends or when I need to drive it.
    colin.

    Save the whales Harpoon a fat chick.
     
  3. solowookie

    solowookie 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    well I'm getting about 12 right now, but I feel this coming into its own more, and more all the time so I'm not sure I don't have chrome rings...

    anyway I got two things that I believe are really hurting my performance / MPG... first when they did my exhaust Y they didn't have enough space so they made a T instead... second is that I have a 454 TBI, and I didn't get the intake bored out to be the same size so I got a shelf there...

    I'm betting I can gain a solid 3-4 MPG just with those couple changes. so I'm hoping to get 15-16 all said and done. (oh yea, and my power range is too high so I need to advance my cam also as part of this about 10 degree's) it kicks in really well about 300-400 RPM above my cruising speed.

    <font color=blue> Jeff - may the force be with you</font color=blue>
    <a target="_blank" href=http://coloradok5.com/gallery/Jeffs-Stuff>link to k5's</a>
     
  4. chevyracing

    chevyracing 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    I have a 383, Holley 750, Erson TQ-20 cam, TRW forged pistons, 9.5:1 compression, headers into duals, no cats, Weined (&lt;&lt;&lt;&lt;--------spelling) intake, 1.5 Erson roller rockers, 2.02 heads, 465 4 speed, 205 transfer, 3:73 gears, little 33x12.5.15's, and a size 12 boot. I get around 10 MPG on the highway if the wind is not too strong, I live in Eastern Colorado where the wind is always too strong. I have the standard small tank in my 72 Blazer and at around 175 miles on the tank I am scouting for gas. Gawd I need a fuel tank that holds some fuel.

    Like to go sloppin' 'round in da mud in a rapid fashion....=) [​IMG]

    <a target="_blank" href=http://community.webshots.com/album/23622937JIJjTHhZPo>http://community.webshots.com/album/23622937JIJjTHhZPo</a>
     
  5. AussieK5

    AussieK5 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    K5 327/350/203 3.42 on 33s....runs straight propane and gets 11mpg hwy, would be close to 13-14 on petrol (gas). Propane cam, single plane manifold, single 3" pipe no muffler just resonator, mech fan (flex), HEI, pwr steer, foam air filter

    K20 305/465/205 4.10 on 33s ...lucky to get 9 mpg hwy. Dual plane manifold, ramshorns into dual 2.5", mech fan (plastic), Holley 600 sec vac, standard dizzy, old paper air filter....this is my new truck and needs lots of attention...plugs, dizzy upgrade, O/D, headers etc
     
  6. solowookie

    solowookie 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    oh yea... my setup

    Vortec Heads, Crane Cam # 114122, custom chip from fastchip.com, 454 TBI, GM perf intake for TBI, flowtech ceramic coated afterburner headers, gibson catback exhaust...

    <font color=blue> Jeff - may the force be with you</font color=blue>
    <a target="_blank" href=http://coloradok5.com/gallery/Jeffs-Stuff>link to k5's</a>
     
  7. AussieK5

    AussieK5 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    Whats your trans/diff/tire combo or rpm at cruising speed? ......I have to replace the 305 in the near future and if you can get 15 mpg (hwy) out of a BB I'm getting damn excited with the possibilities.....15mpg would suit me fine and I could do a BB for just a little bit more than a SB.
     
  8. CaptCrunch

    CaptCrunch 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    What kinda setup is that jeff [​IMG] LOL [​IMG]. I would say you could definetly tune the TBI for fuel economy, but of course you would sacrifice some power. I would bet a lot is in the chip, because I would think stock you would get at least a small boost from Vortec heads.

    Yeah the way I look at things it is gonna be a 10-12 mpg almost anyway you go except not sure on the tpi vehicles

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  9. four_by_ken

    four_by_ken 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    Daily driver/ tow vehicle.... '85 Suburban. 454(carb), 400 trans, 4.10 axles, 33 inch tires. I get around 8-9 street/highway, and 7-8 towing. The motor is built nicely.

    Ken H.

    '85 K5 in process
     
  10. delta9blazer

    delta9blazer 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    '89 fuelie, no motor mods. 170,000 on the clock. when i had 33's, i got 13-15 all day long, and i'd flirt with high teens on the freeway. i haven't re-geared to compensate for the increase in tire size (33's to 35's), so i think i'm down to 10 or so.
    but now my wife doesn't work, so she uses the blaze to take the kids to school (the dogs get pissed if they can't go), so i'm getting around 27mpg in her honda!

    <font color=purple>delta9blazer</font color=purple>
     
  11. 83ZZ502_Jimmy

    83ZZ502_Jimmy 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    This is what i was getting with the manual, haven't tried the auto yet..

    83 GMC Jimmy

    4" w/35"' all terrains
    ZZ4 crate motor- 750 carb
    465 trans
    3.42 gears 12/10 bolts

    13-14 mpg

    <font color=blue>"When all else fails, read the instructions, or get a bigger hammer"</font color=blue>
     
  12. CaptCrunch

    CaptCrunch 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    What gears do you have Delta? 3.73's?

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  13. Thunder

    Thunder 3/4 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    Ok i'm prepaired to be slammed because everytime I post my gas milage no one believes me. But as far as I know no one on this board has done the things to their K5 that I have.
    BUT if i take it easy I usually get around 20 mpg average all around milage. Of course it drops off if I do a lot of four wheeling, drive over 70 mph, Or mash the throttle all the time.
    Heres a list of my mods.
    First of all my K5 is a daly driver and is not lifted. Lifts and gas milage dont mix.
    I have a Stock TBI 350, 700r4, 3.73 gears /lockrite 10.50x31 tires. 78000 miles on the spedo, which I have checked over a measured mile and found to be accurate.
    Engine mods: Edelbrock TES, Single 3" ex with a Flowmaster 70 series, MSD 6-a ign, accell cap and rotor, autolites gapped at .50 thousands, K&amp;N filter.
    TBI mods all came from http://coloradok5.com/gallery/Thunders-Blaze
    <font color=blue>NEVADA: Where the pavement ends, and the West begins.</font color=blue>
     
  14. HarryH3

    HarryH3 1 ton status Author

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    The rig: A 75 K5 with 3/4-ton axles, 4.10 gears, a Turbo 400 and 35 inch BFG's.

    The engine: TPI 383 with Corvette aluminum heads that have been ported. Lingenfelter runners, attached to heavily ported intake plenum and base manifold. Corvette factory headers, feeding into dual Borla mufflers. Mid-range cam from Comp Cams, 26 lb/hr injectors.

    Highway: 13.5 mpg
    Trail: Don't check it. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  15. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    OK, I'll chime in with my own specs:

    '72 K5 CST
    427BB Motor - 396 w/454 Crank
    9.75 : 1 Compression
    Crower Cam .520 lift / 292 Duration
    Roller Rockers
    Edelbrock 1407 750CFM Carb
    TH350 Trans
    NP205
    35" Tires
    3.73 Gears

    I've kept a log of every gallon of gas I've put into it since I bought it. The best mileage so far is 10.79 mpg....the worst is 6.30 mpg.

    The motor has a total of 2362 miles on it since it was built, so the 'newness' shouldn't be an issue.

    I suspect there are some things giving me artificially LOW mileage, that I would like to address:

    1. Ignition - Adding an MSD-type box would give me a better burn and probably more power with less throttle.

    2. Carb Jetting - I'd really like to see if the carb is setup over-rich. I'm not particularly fond of the carb that's on there....I'd really like to get a well setup Q-Jet, so I could run on the small primaries most of the time.

    That's all for me....hope it helps [​IMG]


    -Greg72
     
  16. solowookie

    solowookie 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    tranny is a 700r4, 4.10 gear ratio with BFG 33x10.5x15 (actualy height is 31")... cruising speed (don't have a tach so I'm using the RPM calculators) is right around 2400 RPM on interstate at 75...

    <font color=blue> Jeff - may the force be with you</font color=blue>
    <a target="_blank" href=http://coloradok5.com/gallery/Jeffs-Stuff>link to k5's</a>
     
  17. solowookie

    solowookie 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    yea, capt says that tongue in cheek because, other then my cam, he basically hand picked / convinced me which way to go on this setup... I gotta admit he did a really good job!

    one of these days I'm gonna have to publically tease him about a small part of this... [​IMG][​IMG][​IMG] LOL

    <font color=blue> Jeff - may the force be with you</font color=blue>
    <a target="_blank" href=http://coloradok5.com/gallery/Jeffs-Stuff>link to k5's</a>
     
  18. Boss

    Boss 1/2 ton status Author

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    Stock TBI 350. No motor mods, except for K &amp; N filter and Freeflow cat and muff. 3" exhuast, no headers. R4 tranny. 1 ton axs with 4.56 and detroit and 36" TSL rads. 4 - 5" lift, 1" body.

    12 to 13 mpg----city/hwy.
    Boss

    Pic of my truck Before N' After
    <a target="_blank" href=http://coloradok5.com/gallery/BeforeNAfter>http://coloradok5.com/gallery/BeforeNAfter</a>
     
  19. GONZO2

    GONZO2 1/2 ton status

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    my wife's 88 gets 10-11mpg around town and 13.5-14 on the highway. this is a completely stock engine(350) and drivetrain. only deviation from stock is 33" tires. i think fuel economy would improve if it was regeared to 4.10 because right now o.d. is almost useless unless you are on flat straight highway. truck originally had 235/75 tires so whatever crappy gear came with those is what it still has.
    my 85 blazer is lucky to get 13mpg on the highway and 9mpg in town. 85 has a 350 rebuilt to stock and th350 on 32" tires. that was before the regear to 4.10 and the lift. fuel gauge is broken now, but somehow i don't think i want to know anymore.

    <font color=blue>85 blazer</font color=blue>
    <font color=blue>88 blazer</font color=blue>
    <font color=blue>99 30th ann. TA</font color=blue>
    <font color=blue>79 TA</font color=blue>
     
  20. Doug

    Doug Registered Member

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    Re: Gas Milage... no this isn\'t the same ole whiner post

    I've got a completely stock '85 California emissioned 350 (I'm in Colorado), with a computer controlled Qjet that runs like SH!*. I hope to convert to TBI very soon. Right now I'm getting 11-11.5 mpg hwy.

    '85 K5, 350, 700r4, np208, 10 bolts, as of 10/2001; wish list is extensive.
     

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