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Fuel injection vs. Carb MPG

Discussion in 'The Garage' started by terrier72, Oct 10, 2005.

  1. terrier72

    terrier72 1/2 ton status

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    DO those with fuel injection get a lot better mileage than those with a carb? I was wondering if anyone here could give me a comparison of the carb and fuel injection mpg after they converted. I guess i am wondering if i really want to convert mine from carb to fuel injection.
    Thanks
     
  2. 79k20350

    79k20350 3/4 ton status

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    i noticed a 2-3 mpg differance from a great running carb system to great running efi. not really worth $1200.00+ if all your looking for is better mileage
     
  3. u2slow

    u2slow 1/2 ton status

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    IMO, no.

    Best I ever got with a 350 TBI on my crewcab was 12mpg (strictly highway @ night). Otherwise 10mpg at best - usually 8-9mpg.

    Thats with 4.10s, 33s, SM465, dual exhaust, and rams horn manifolds.

    I think changing axle/transmission gearing yield greater benefit.
     
  4. Leper

    Leper 1/2 ton status

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    You will get a bit better mileage with the injection. The real plus to injection is the reliability. No more cold start problems or angle problems when on the trail.
     
  5. arq

    arq 1/2 ton status

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    If you keep it at 55, your mpg will go up to. I've noticed 3-4 mpg when driving 55 than 70. gearing and speed plays a lot in it.

    ARQ.
     
  6. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    As long as I stay in my elevation , and not drive the truck uphill to Moab , I can knock down a 15 mpg average with my q-jet and 700r4 :D
     
  7. warrior454

    warrior454 1/2 ton status Premium Member

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    I went from 350 TBi to 454 with an 800 double pumper and get same mileage and having twice the fun
     
  8. 79k20350

    79k20350 3/4 ton status

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    1 of two things, dont take this the wrong way but, your either lying out your teeth or there was something wrong with that tbi setup theres no way, no way even a perfectly tuned 454 w/ an 800 duble pumper will get the mileage a 350 tbi setup does. Dont mean to argue but its just the way it is.
     
  9. sweetk30

    sweetk30 professional hooker Premium Member

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    tbi is better throtle responce and more tourqe faster. if you want to look at kits or need just the harness and pick a part the rest of the stuff then look hear also. www.howell-efi.com
     
  10. warrior454

    warrior454 1/2 ton status Premium Member

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    Was a factory 88 TBI i had done mods to the TBI (ie raised the injectors)
    and no i aint lieing i ran down the road at 10 inches of vacuum with the tbi and same speed getting 16 with the 454 its not working no where near as hard moving the truck, i dont know maybe just got lucky with combo of cams and such, and maybe had the wrong one in the 350, Lol ya sound like my co-workers, most ppl find it hard to beleive big blocks can get mileage
     
  11. Pookster

    Pookster 1/2 ton status

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    If your BBC is getting 16, I'd sell that motor to GM for a million bucks. Cause something you have has eluded millions of development dollars and thousands of engineers, and hundreds of prototype motors.

    Not even the latest generation BBC with fancy electronic multiport fuel injection can come close to getting 16. (in a 1 ton truck).
     
  12. warrior454

    warrior454 1/2 ton status Premium Member

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    well maybe clear something up here canadain gallon is 4.5 litres where us gallon is 3.78 causing mileage to compute higher here and fathers friend claims he got 18 out of his 8.1 litre 2004 silverado, who knows for sure
     
  13. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    I havent put a straight highway trip to calculate that, but so far, its been getting a little worse then my carb, which sucks. It could be a few different reasons though, one being its more fun to get on?!?!? I actually didnt get too bad of mileage when I was carbed though.
     
  14. u2slow

    u2slow 1/2 ton status

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    That's not unheard of with a BBC.... easy enough with a manual trans, highway gears, and lots of highway miles. ;)
     
  15. tch777

    tch777 1/2 ton status

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    I think something is up here your signature says you are running:
    Drivetrain/Suspension:
    454 35 inch BFGs 4.88s 14b rear axle

    With your set up you are not running a Big Block in its most effiecient rpm range you are more in its power range for towing.
    So if the gallon thing is true, 3.78/4.5= .84 = 16% difference.
    So 16 x .84 = 13.44.
    Which is closer to the best I have ever heard of a 454 doing, at around 12 MPG.
    But with your set up I wonder if your Speedo is accurate, since you are running the rpms a little high for maximum MPG?

    18 x .84 = 15.12 miles per gallon, sorry not in a million years. Best I have actually seen calculated milage for one of those is 7 MPG, they are gas pigs!

    Tim
     

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