379 mpg

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

  1. sharpshooter

    sharpshooter Medium Load Member

    Jun 20, 2010
    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.
  2. REDD

    REDD The Legend

    Jun 29, 2009
    Dueling Banjoville
    The 379 I had with a C-15 pre-emmision CAT, 10 speed eaton, & 3:55 rear gears was averaging 5.4 mpg.
  3. doublew

    doublew Light Load Member

    Oct 17, 2010
    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
    KB3MMX Thanks this.
  4. Les2

    Les2 Road Train Member

    Jul 25, 2008
    kicked back in my lazyboy...
    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.
    KB3MMX Thanks this.
  5. Markvfl

    Markvfl Road Train Member

    Nov 29, 2007
    Apopka, FL
    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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  6. Flying Finn

    Flying Finn Heavy Load Member

    Jun 22, 2010
    Ontario, Canada
    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.
    bigeazy12 Thanks this.
  7. Krooser

    Krooser Road Train Member

    Jul 25, 2010
    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.
  8. zircon

    zircon Bobtail Member

    Mar 12, 2010
    Austin Texas
    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
    Slick Ruler and freightlinerman Thank this.
  9. sharpshooter

    sharpshooter Medium Load Member

    Jun 20, 2010
    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
  10. thunder lilly

    thunder lilly Bobtail Member

    Jan 24, 2011
    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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