Increasing MPG pete 389

Discussion in 'Peterbilt Forum' started by Wespipes, Feb 2, 2020.

  1. Wespipes

    Wespipes Road Train Member

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    Been trying to find ways to increase MPG.

    1st, 19' pete 389 70k miles mid roof 3.25 gears 18 speed 11r24.5's cummins 565 1850.

    I'm averaging 5.5-6.5, 5.8 seems to be the norm

    So I'm looking at the bully dog tuner, after market manifold or intake, maybe maybe upgraded air filters. Just curious on what others have done to help. If any of what I mentioned is even worth it or even helps.
     
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  3. Bakerman

    Bakerman Road Train Member

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    Keep a light foot on the skinny pedal and watch your boost gauge, lower boost equals better fuel mileage.
     
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  4. Wespipes

    Wespipes Road Train Member

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    I try to keep it under 20
     
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  5. Snow Monster

    Snow Monster Medium Load Member

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    Before you start spending money, maybe for nothing, try this.
    Keep it under 70 mph and under 1500 rpm.

    I drove a 1996 W9 with a 3406E @ 550 hp, 3:25's on 22.5 rubber and that truck was driven below 1400 rpm at cruising speed, (65 to 68 mph), one of 20 trucks with a fleet average of 6.7 mpg.

    Your truck is a little faster with big rubber and if you're only pulling 80k or less try cruising between 1250 and 1400 rpm and play with it.

    If you're bucking wind or on a long slow rising grade, and the engine is working try dropping a gear and see what that does.
    An estimate on my part, that truck should still run 65 to 68 mph at 1500 rpm or less if you drop a gear and you should see a drop in EGT and turbo boost under heavy pulling conditions.

    Maybe try both throttle programs to see which one best fits your driving style or you prefer.

    I suggest you optimize what you have before you start changing things, so if you do change something you'll know for sure what and how much you gained.

    Other than that, make sure your filters are clean and your tire pressures are optimized, happy motoring.
     
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  6. Mattmanstroked

    Mattmanstroked Light Load Member

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    What are you pulling?
    What speed and where are you driving?

    Speed eats up fuel mileage.
     
  7. Zack.Boswell

    Zack.Boswell Bobtail Member

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    I know this is an old thread, but I wanted to continue the conversation on Bully dog tuners. I’ve seen a lot of people saying to get them or to not get them. But I’m curious to hear anyone’s comments on how long they have been using them. Are they good tunes to use long term? It’s all good if you can pass everyone up a hill.. But how many times can you climb that hill for the years to come? Looking forward to any replies.
    Thanks
     
  8. SmoothBore

    SmoothBore Medium Load Member

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    Trade it in for a cascadia, problem solved.
     
  9. Cat sdp

    Cat sdp . .

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    pfffft……
     
  10. Zack.Boswell

    Zack.Boswell Bobtail Member

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    Haha.. funny..
     
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