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  1. #1
    Jr. Apprentice
    Join Date
    Jul 2012
    Location
    Calgary, AB, Canada
    Posts
    28

    Default gas mileage, what do you guys get?

    I HATE when people talk about gas mileage on the jeep forums I visit, but i'm going to post one too. my 13' Sierra is getting 15.2 L/100 km. about 16 mpg. I drive mostly highway. do you guys get similar numbers? i'm not complaining. but I thought with the 6 speed tranny i'd get better than the old 4 speed, and its not. 5.3l motor. no mods, stock tires. yes I drive to fast. 120km/h (75 mph?) the sticker/factory numbers were a lot better though.
    05' GMC Sierra 1500 quad cab 5.3L Daily Driver and tow rig

  2. #2

    Default

    Its hard to match the factory numbers, those are under specific driving conditions which dont match real world driving, I was at 17.9 with the 5.3 4x4 z71 6 SPEED, I am at 19.1 after adding the AFM kill , K&N and nitro to my tires, beats me but thats the real numbers, I am 65 to 70 mph more than not. 19.1 is up from a starting point of 17.9, it seems like the little things you do make up several slight improvments, basic of 1.2 increase If you factor 200 bucks for the AFM device, 225 for K&N, and 50 bucks for nitro fill, im about 500 bucks for a 1.2 MPG increase, ( K&N and nitro is something I do on all my vehicles, it wasnt to improve, it just does somehow). I am happy as a freed canary at 19.1 MPG. I know some guys here post great numbers, and some not so great, I bet you get some good advice on this from others in here, good luck.
    Life is short compared to history

    Rick (summitwhite11)

  3. #3

    Default

    Quote Originally Posted by JohnnyZJ View Post
    I HATE when people talk about gas mileage on the jeep forums I visit, but i'm going to post one too. my 13' Sierra is getting 15.2 L/100 km. about 16 mpg. I drive mostly highway. do you guys get similar numbers? i'm not complaining. but I thought with the 6 speed tranny i'd get better than the old 4 speed, and its not. 5.3l motor. no mods, stock tires. yes I drive to fast. 120km/h (75 mph?) the sticker/factory numbers were a lot better though.
    x2.....On what summitwhite11 has mentioned above.....Its hard to match the factory numbers.....when your driving at (75 mph?) While each Vehicle Reaches its Optimal Fuel Economy at a Different Speed (or Range of Speeds), Gas Mileage Usually Decreases Rapidly at Speeds Above 50 mph, and but After 60 mph it Generally Declines Quite Significantly, and from 50 to 60 mph Fuel Economy Drops by 12%, from 50 to 70 mph it Drops by 25%, and from 50 to 80 mph it Falls by 36%.

    I would also mention that another reason for your Drop in Fuel Mileage, is Winter Blend Gasoline.....

    Link,

    http://www.bellperformance.com/blog/...Blend-Gasoline

    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










  4. #4
    Sr. Mechanic poncho62's Avatar
    Join Date
    Sep 2013
    Location
    Hanover, Ont, Canada
    Posts
    173

    Default

    Quote Originally Posted by JohnnyZJ View Post
    I HATE when people talk about gas mileage on the jeep forums I visit, but i'm going to post one too. my 13' Sierra is getting 15.2 L/100 km. about 16 mpg. I drive mostly highway. do you guys get similar numbers? i'm not complaining. but I thought with the 6 speed tranny i'd get better than the old 4 speed, and its not. 5.3l motor. no mods, stock tires. yes I drive to fast. 120km/h (75 mph?) the sticker/factory numbers were a lot better though.
    Yup...slow down....the faster you drive, the worse it will be. I think you are lucky to get what you are getting. Also, it had been real cold in the great white north this winter. You mileage will be greatly affected by the cold weather too.

    [B]1997 GMC

  5. #5
    Legend
    TRPLXL2's Avatar
    Join Date
    Jan 2009
    Location
    Norwalk, Ohio
    Posts
    3,359
    Blog Entries
    8

    Default

    Gas mileage right now for me is
    05 2500hd 6.0-12mpg
    13 camaro 2ls 24.5
    2004 Chevy Colorado
    LS1 5.7 swap/TBSS rear axle swap

  6. #6

    Default

    I get about 14mpg, I have 285/75/16's, 5.3, 4l60e, 3.73 gears, and dual exhaust.

  7. #7

    Default

    Really? I heard the 'sweet spot' for most vehicles was around 55 mph for optimal fuel economy.

    but anyway.

    (With 3.42 gear ratio, 4L60-E Automatic, P245/75R16 tires)

    In summers, I get 14 driving around town, 18 or 19 on highway. Winter I get 11 or 12, maybe 15 highway.
    Dallas Rourke Smith
    1993 Chevrolet K1500
    - Regular Cab, Long bed - 5.7L 350CI Small Block V8 - 3.42 Gear Ratio - Built at Fort Wayne Assembly Plant, Indiana

  8. #8
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,324

    Default

    with highway speeds @75MPH you will get lower MPG. My 2000 4X4 5.3L ext cab gets 18-19 MPG @70MPH max speed on the high way trips in summer. when the cold weather comes this drops down to 17MPG. cold temps and high speed will drop the MPG.

    when driving do not hit the throttle down fast , as this will greatly reduce MPG. Change speeds slowly.

  9. #9

    Default

    On my 2013, 5.3L, 4x4, I get about
    17.5 avg city driving on M5., AFM OFF
    18.5 avg city on D, AFM ON
    19-20 avg high way at 75mph

    2001 burb
    16-17 avg city
    18-19 avg high way at 75mph
    2011 Chevy Silverado LT 4WD 25k miles
    2001 Suburban 2WD, 5.3, V8 176k miles
    1993 964
    1996 318TI

  10. #10

    Default

    My '96 7.4 has gotten as high as 12mpg straight highway to as low as 8.6 in the city.
    I like all dogs I meet, and some people too.

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