379 mpg

Discussion in 'Peterbilt Forum' started by sharpshooter, Oct 31, 2010.

  1. sharpshooter

    sharpshooter Medium Load Member

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    Jun 20, 2010
    NC
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    I'm looking at buying a truck. I really want a used 379 or W900. I was just wondering what kind of mpg you all are getting. I know it depends on alot of variables but, I'm just curious if it's really that far off from an aero.
     
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  3. REDD

    REDD The Legend

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    Dueling Banjoville
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    The 379 I had with a C-15 pre-emmision CAT, 10 speed eaton, & 3:55 rear gears was averaging 5.4 mpg.
     
  4. doublew

    doublew Light Load Member

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    Oct 17, 2010
    Kansas
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    you hear a lot of storys about those 7.0 mpg trucks but i have never seen or drove one and yes it depend a lot on motor,gears and so on but mostly depends on how heavy your foot is i think 5.0 - 6.0 is a good range i have 3 mid 90s 379 with 3406e a 87 359 and a 86 w900 both with 3406b and they all get in that range mpg.my opinion is aero dont really make a lot of diffrence
     
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  5. Les2

    Les2 Road Train Member

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    kicked back in my lazyboy...
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    Have you ever owned an aero truck? I'm guessing not with that last statement.
    My dads 2 trucks...

    88 W900B 3406B, 22" bumper, pulling a covered wagon and dad has gotten as high as 6.5 but on average its 6.2. ALmost forgot, fuel is turned to it too.

    96 Classic 3406E 550 with a unibilt style sleeper, pulling a covered wagon and when dad was runnign it he could get 6.5 at best but most of the time it was 6.2/6.3.

    My truck....

    93 FLD120 3406B, flattop with chicken wing, pulling covered wagon got as high as 7.2 but on average its 6.8. Yep fuel is cranked even more than the 88's. I've got a bigger turbo and injectors in mine. Can turn the sky's black....:biggrin_255:

    I do believe alot of fuel mileage is determined from the start of going thru the gears but the aero helps when going down the road.

    Throw a cowboy in the most aero truck in the world and he will get bad MPG's, but throw the easiest driver in a non-aero truck and he will help the MPG's alot.
     
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  6. Markvfl

    Markvfl Road Train Member

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    Apopka, FL
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    If you plan to get any fuel mileage from a 379 you better get used to driving under 60MPH. I've tried everything under the sun and the best I can get is 6.3 to 6.4MPG. I have a CAT ACERT with (sniped), free flow mufflers, etc, etc. I have a 13 speed with 3:36 rears on 22.5s. My trailer is an aerodynamic nightmare - a double drop RGN so that doesn't help. Actually since I put on new tires and bought a new trailer I'm down to 5.7.

    On the other hand I have a friend who drives 60MPH in his 06 Century with the same power train I have except he has a (sniped) pulling a reefer and he averages over 7.5MPG. He's probably a little more careful about his driving than I am but I'm no Billy Big Rigger - Swift trucks pass me.

    My point is - if you're priority is fuel mileage and making money then an aero truck is a no brainier choice. If you want to truck for glamour and glory buy a 379. An areo truck set up and driven correctly pulling a reefer or van will put an extra $10,000 to $20,000 a year in your pocket.
     
    Last edited by a moderator: Aug 2, 2014
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  7. Flying Finn

    Flying Finn Heavy Load Member

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    Jun 22, 2010
    Ontario, Canada
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    I can tell you my experience in an '08 389 Pete. A lot of the miles were done with a leaking EGR system that oddly dealers could not figure out. LOL As well as a very plugged DPF. So my mpg ratings were lower than they could have been.

    According to our fuel/mileage reports from the company (all lease ops so we get true fuel numbers and have our mileages on hand anyway) I was still one of the best trucks for mileage. On average I was getting 7.5 mpg over 6 months. That is with loads ranging from the lightest at 10,000# to just over 50,000#. Average load was pretty much 38,000#. Running all over North America, lots of Rockies.

    Here is the kicker, truck was limited to 105Kph. So I didn't really care, I would just set the cruise to 58 mph and go. Our other truck, '94 KW 600 with a CAT, was wide open. Driver ran it that way too. His average over the same time, and with VERY similar loads, was about 5.6mpg. The KW was rebuilt a couple of years ago, heck it checked out in better shape than my '08.

    The biggest difference was the nut between each of the steering wheels and the seats. I ran his truck for a week with him team. I could get MUCH better mileage off the tanks than he could. Mainly because I just set her to cruise at 58mph or so.

    You know, every time I get my doors blown off by some wannabe cowboy trucker doing 70 or 75 mph. I have to smile and laugh because I will pass him down the road as he is fueling up and I still have over half tanks.

    Remember, it is true that pretty much every 10 mph you go over 55 in a rig you lose at least 1mpg. Doesn't seem like much until your run is 3600 miles long. Then the $$$ really add up fast. I don't like speed limiters and hate having one on the truck. I have had too many times with young dipstick college kids that know we cannot hit over 65 screw with me. I would love to have the extra speed available since my rig could overtake their civic in most cases. I do agree with the slower is better and makes you more money idea though. I know the owner of my truck loved getting my fuel bills over the other drivers. Mine were WAY lower.
     
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  8. Krooser

    Krooser Road Train Member

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    Jul 25, 2010
    Wisconsin
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    My lifetime on the ECM is 6.32... '95 379 3406E/435 HP/3.36/15 over. That acerage is pulling a reefer and my flatbed plus open tops, insulated vans and bean wagons.

    My last IFTA report was at 7.43... but I had a few bobtail miles in there.
     
  9. zircon

    zircon Bobtail Member

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    Mar 12, 2010
    Austin Texas
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    i drive a 2000 379 with a 500hp series 60 detroit. i get 6.5 to 7.3 mpg with a 13 speed and 3.54 rear end. i try to stay around 65 mph pulling aflat bed around texas. i am very pleased so far with my detroit. i here similar reports from other detroit owners. zircon
     
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  10. sharpshooter

    sharpshooter Medium Load Member

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    Jun 20, 2010
    NC
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    That sounds good. I also like the detroit, got good mileage and was smooth. My experience wasnt with a hood though, that's why I was curious. Sounds like they do fine if kept under check
     
  11. thunder lilly

    thunder lilly Bobtail Member

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    Jan 24, 2011
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    got a 97 pete 379 with cummins,3.7 rears,10 spd , low rolling resistance tires, at 55 mph with 44 thousand pound load, will average between 6.5 to as high as 7.25, depending on a weather, in summer I get over 7 mpg on daily basis. Every time I go over 60 mph it goes down a lot, into fives which cost me a lot of money, if I ever buy another truck will definitely go with an aerodynamic truck.
     
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