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How can I get better gas mileage from my 350?

Discussion in 'The Garage' started by joey90, Dec 30, 2003.

  1. joey90

    joey90 Registered Member

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    I have a 1990 Suburban with the 350 engine. Just wondering what I can do to squeeze an extra mile or two from each gallon, aside from regular engine maintainence. It's all stock except i'm running 35's.
     
  2. txbluethunder

    txbluethunder 1/2 ton status

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    stay below 60mph...i noticed a significant increase in gas mileage if i didn't go faster than that.
     
  3. SUBFAN

    SUBFAN 1/2 ton status

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    Just a bit more information please....

    Are you running crappy gears and trying to use the OD?

    More later when I see more to work with. Our vehicles may be very similar....
     
  4. joey90

    joey90 Registered Member

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    Hey I dunno what my gear ratio is, whatever came stock. And it doesn't have OD, it has the Turbo 400 tranny.
     
  5. sled_dog

    sled_dog 1 ton status

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    my burban has a 4 speed, 3.42 gears and so far seems to be getting about 12 mpg around town. You just need to stay calm on the throttle, thats the best mileage increase.
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    A strong ignition is supposed to help, make sure the carb is jetted and tuned right, and if your running tall gears than that is your biggest gas sucking problem. If it is totally stock I bet you have 3.08's,3.42's, or 3.73's. The higher the gears the worse. With 35's you would wan't like 4.56's or 4.10's if your motor makes good low end power and you do a lot of highway driving.
     
  7. joey90

    joey90 Registered Member

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    I don't have a carb, do I? it has TBI. I know I need to regear but I wanna go with larger tires before I do that. Havent decided what size I wanna run yet but I'm thinkin at least 38's. I'm wondering how much of a gain I'd get if I upgraded the ignition. What about exhaust/headers/intake? any mpg to be found there? I'm stock in that department too.
     
  8. SUBFAN

    SUBFAN 1/2 ton status

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    Drive it like there is an egg under your throttle foot. Use momentum as your friend.

    Having the right gear ratio is helpful too. A Burb on 35's will always get crappy mileage around town. If you are doing mostly freeway driving, then keeping the speed reasonable will help a lot. With these big sails up in the wind fighting it sucks down lots of fuel.

    A big improvement on mine was an exhaust upgrade as the stock converter was really plugged up with 300,000 + miles of use.

    Keeping the oil fresh is worth 1-2 mpg in most vehicles too....

    I haven't tried this on the Burb yet, but I had a '90 T-Bird that could get 34 mpg on the highway with all synthetic fluids, careful throttle control, and the A/C running full bore.

    Fill out that profile, I am interested in what is on your rig....
     
  9. sled_dog

    sled_dog 1 ton status

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    I guess exhaust and all can help but personally they lower my MPG. Cause I get on it all the time since it sounds nice when you do /forums/images/graemlins/smile.gif
     
  10. 84_Chevy_K10

    84_Chevy_K10 Banned

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    My 1 ton has 4.10s, 31s, a TBI 350, and a TH 400 and averages 14 MPG! Gears are your friend.
     
  11. joey90

    joey90 Registered Member

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    which profile are you talking about? lol.

    so when you did your exhaust you replaced your cat too?
     
  12. Z3PR

    Z3PR Banned

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    [ QUOTE ]
    I have a 1990 Suburban with the 350 engine. Just wondering what I can do to squeeze an extra mile or two from each gallon, aside from regular engine maintainence. It's all stock except i'm running 35's.

    [/ QUOTE ]First thing too keep in mind is that your 1990 Suburban isn't the most fuel efficent vechile, and the more mpg's you squeez out of it, the weenier it'll become. Best thing in my opinion is buy a little gas milage car for those mpg's, and build your burb to drink gas like most people drink beer. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  13. sled_dog

    sled_dog 1 ton status

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    [ QUOTE ]
    My 1 ton has 4.10s, 31s, a TBI 350, and a TH 400 and averages 14 MPG! Gears are your friend.

    [/ QUOTE ] I have to agree, I had 2.73s and 33s in my k5 and it got 6 mpg. You had to work it so much just to move and not hold up old ladies that it killed the mileage.
     
  14. joey90

    joey90 Registered Member

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    lol i gotta believe there's ways to squeeze mpg and increase power. there has to be! /forums/images/graemlins/laugh.gif
     
  15. sled_dog

    sled_dog 1 ton status

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    you need to understand something, power is made one of two ways, passing fuel through the motor, and burning it efficiently. So to make more power you have to pass more fuel through the motor, and burn it more efficiently. The ignition suggesstions take care of the burning it more efficiently. I'd definetally look at a coil, $40 its worth a shot. An exhaust will help flowing fuel through the motor but at a point to make power you need to then introduce more gasoline, which will never produce more mpg. By the way my burb getting 12 mpg makes me VERY happy. Thats THE best mileage I've gotten in any vehicle i"ve owned since I got my license. My 95 with 29s and 4.10s maxed out at 11 mpg highway. My blazer has never broken 8.
     
  16. joey90

    joey90 Registered Member

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    haha wow that's crazy! 8mpg, that's just like my old bronco. so what other ways are there of burning it more efficiently? how the hell do they squeeze 20mpg city out of that 405hp Z06 vette?!
     
  17. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    You can make a Sub get 30+mpg.
















































    Just take a sawzall and cut off everything that doesn't make it go foward. Once you loose about 3500lb is will get pretty good mpg. /forums/images/graemlins/rotfl.gif

    This is heavily discussed. Might search for some of the old posts.
     
  18. sled_dog

    sled_dog 1 ton status

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    a much better form of fuel management, aka really good fuel injection. TBI sucks in the scheme of fuel injection but its still fuel injection.
     
  19. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    how the hell do they squeeze 20mpg city out of that 405hp Z06 vette?!

    [/ QUOTE ]
    Because it weighs half as much as your burb and has the latest technology on fuel injection on board.
     
  20. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    [ QUOTE ]
    I don't have a carb, do I? it has TBI.

    [/ QUOTE ]
    Your correct, sorry, I missed that it was a 90' /forums/images/graemlins/tongue.gif /forums/images/graemlins/grin.gif
     

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