help with LLY Dually

Discussion in 'GM Duramax 6.6 (LBZ | LLY)' started by limitedstreet, Dec 26, 2007.

  1. limitedstreet

    limitedstreet Member

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    I have a 05 LLY Dually that gets around 12.5 mpg city and 9 towing a gn with a total weight of 24k. the truck is totally stock. I have a Magnaflow exhaust, and a k&n filter for it. have'nt installed yet due to time....
    What chip performes best. Also would like to install the 235/27 tire on it. Any suggestions would be appreciated.
     
  2. RodZZilla

    RodZZilla Well-Known Member

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    If you drink enough, you will forget it is Iowa
    The exhaust will help MPG some. It will help keep the EGT's down, too. I haven't experimented w/ Tuners yet. I have had good luck w/the PPE. I have kicked around either EFI Live or going w/a pre done tune such as Kennedy Diesel's.
     
  3. Bourdon1350

    Bourdon1350 Well-Known Member

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    For a dually that doesnt sound to bad. But i think an intake, exhaust, and chip should bring ya up 2-3 mpg if you drive it right. Bully dogs help mileage alot. And id say AEM dry filter intake.
     
  4. limitedstreet

    limitedstreet Member

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    update

    I just put a magnaflow cat back exhaust and did the air box mods, per Kennedy Diesel website with a foam filter. Also installed 235/85 tires.
    Considering banks six gun, or edge, hypertech, or the new superchips tuners. I have to tow a good bit, so looking for protection. Don't race it or pound on it, just use it......Which one?
     
  5. PC HOTROD

    PC HOTROD Member

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    I'm running a 2006 GMC LBZ/Allison DRW along with the Superchips/Flashpaq Programmer. The best MPG i've ever seen was running empty from about 60 - 75 mph on a 2 hours trip and hand calculated at 19.5 mpg while still sitting on the stock tires and using the Performance Tune. With the factory tires and using the tow/performance tune and towing our 22'x7' enclosed trailer weighing in at 5500lb I would see between 11 - 13 mpg hand calculated.

    I recently installed 6 new BFG AT/KOs that are 235-85-16 and feel a slight difference in performance and a reduction in MPG. The fuel mileage now calculates to about 15.0 - 16.5 mpg city 16.0 - 17.0 mpg hwy when empty and 12.0 - 14.0 mpg when towing the trailer.

    The tuner may have helped increase the mileage by about 0.5 - 1.0 mpg but the added performance is what it's all about. It was the new tires that took the mpg's away but their performance when we find ourselves offshore is worth it.
     
  6. limitedstreet

    limitedstreet Member

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    I am trying the Superchips Flashpaq

    Mileage is better, I don't know how much, waiting to fill up again. Running on the performance/towing setting. I was told by someone that I can tow my 12k racecar trailer on this setting. Is this true?
     
  7. limitedstreet

    limitedstreet Member

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    update

    superchips flashpac tuner set on stage 2 driving easy with a s&b filter setup now gets 15.6. what about that manifold from b&d and a turbo back setup? Again, don't care about racing it, just about towing and mileage
     
  8. RodZZilla

    RodZZilla Well-Known Member

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    If you drink enough, you will forget it is Iowa
    I haven't seen anyone post numbers for the BD Manifold. But it would probably help even the flow from side to side. Better flow from it and the exhaust will help mileage. Mine had the exhaust on when I bought it, so I don't have any comparison numbers.
     
  9. limitedstreet

    limitedstreet Member

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    another update!

    Now have Magnaflow cat back exhaust, superchips/flashpaq tuner set on performance tow setting, and s&b filter setup. Many tanks, hand calculated 16.8 mixed hwy and city driving. Recently pulled a 34' TAG trailer (12000 lbs) to Huntsville Alabama and got 11.3 for the trip. driving @ 65-69 mph. I'm happy with it for now.
     
  10. 1dieselsteve

    1dieselsteve Member

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    Are you still running on petro. oil switch to synthetic you will see about 1-2 mpg.
     
  11. 4054x4

    4054x4 Well-Known Member

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    Sure didn't see any gains when I switched...

    I use synthetic because it cleans better and lasts longer then conventional, not for mileage increases.
     

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