6NZ vs 3406E

Discussion in 'Trucks [ Eighteen Wheelers ]' started by areelius, Sep 27, 2013.

  1. rbrtwbstr

    rbrtwbstr Road Train Member

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    My preference is the 5ek 3406. We have a couple 6nzs and I can't say I'm too impressed with them. (All are bone stock with no mods) the 5ek that I run is set at 550 HP 1850 and i can get 5.7 mpg with a western star 4900ex. On the 6nz equipped trucks I can't even hit 5 mpg. But we run right at 80k in the mountains all the time. And the 5ek just sounds better IMO.
     
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  3. Mr. Haney

    Mr. Haney Road Train Member

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    I would suggest that you never take it to an authorized CAT service center. Otherwise it will be updated to a newer file in the ECM. This will lower fuel mileage and throttle response to a level that is worse then the 550 6NZ engines in your fleet.
     
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  4. rbrtwbstr

    rbrtwbstr Road Train Member

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    in the bush somewhere
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    My engine just was just completely overhauled by a cat dealer and put in a new glider. I have no idea what files they use, I'm guessing whatever epa dictates. Out other trucks haven't been touched and are as they were from factory. Its just my experience that I can seem to do better with a 5ek over the 6nz. I believe both to be great engines though. But you mention throttle response, and the response on a 5ek is rather doggish compared to the 6nz.
     
  5. bull hauler

    bull hauler Medium Load Member

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    Gettin the pre low nox file in these ecms is a must to even give these motors a chance to run good, i stay faaaar away from any cat dealer, at the local cat shop that truck rolls thru the door they plug right into the ecm to update. But my indy cant even plug into As i have my ecm port pad locked to prevent any unauthorized use
     
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  6. rollin coal

    rollin coal Road Train Member

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    The folks who complain about poor fuel mileage from CAT's have probably never driven one tuned right. Who knows if they have maintenance issues and bad driving habits also.?
     
  7. paul 1052

    paul 1052 Heavy Load Member

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    Sand Springs, Ok.
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    The last truck model year for the 6NZ was 2003... I have one in my '03 379.
     
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  8. KW K104B

    KW K104B Bobtail Member

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    Sep 21, 2013
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    In Australia the last model year was 2007 and the prefix was now 9NZ. I have 1 in my Kenny.
     
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  9. The Admiral

    The Admiral Heavy Load Member

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    Akron,Ohio
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    How can I tell what turbo I have? Can not find a tag. Are there numbers stamped in it somewhere?
     
  10. Superhauler

    Superhauler TEACHER OF MEN

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    if it is original take the engine serial# and find out that way.
     
  11. Markvfl

    Markvfl Road Train Member

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    My friend has a 1LW with a pre nox brakesaver 600horse tune and the 74MM turbo. It was just rebuilt again and has 2.7 million miles on the block. It's getting 7.55mpg running 65 - 70 pulling an RGN with mostly legal loads. What a fantastic set up!

    I miss my CAT so much ... this ISX sucks!
     
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