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Thread: 04.5 cummins tune review

  1. #1
    Tuner in Training
    Join Date
    Apr 2011
    Posts
    17

    04.5 cummins tune review

    Hello all. I've been tuning late model GM gas EFI for about 6-7 years, but picked up an 04.5 4x4 cummins truck and decided to try my hand at tuning on it to see what kind of fuel mileage I could get. Mods for the truck are as follows: CAI, full 4" exhaust, Airdog 100 lift pump, Copperhead CP3, built trans with DPC triple disk billet converter, and 2.5" leveling kit with 35' tires on 4th gen wheels. The tune I'm posting got 21.5mpg highway running 75-80 in another truck on 33" tires, but I have not been able to get anywhere close to that with mine (I'm guessing it's the 35's). Please help me review to see where there may be room for improvement. Thank-you.

  2. #2
    Looks pretty good IMO. Your EQ limit of 1 might hold you back in your smoke limit table. Your "part throttle gov" table will limit around 140mm3 you have everything else set to 160 another thing I noticed.

  3. #3
    Overall your tables look pretty decent. Way better than most of the novice tune on here. You've got a great start. Do some data logging and keep picking away at it!

  4. #4
    Tuner in Training
    Join Date
    Apr 2011
    Posts
    17
    Question for you guys. On the smoke limiter table. I?m assuming increasing the EQ ratio it would allow for more smoke if the rest of the tune allows it and lowering the EQ ratio would limit the smoke more. Is this correct?

  5. #5
    It will also limit fueling in general. The computer comes up with an amount of fuel that it thinks equals a stoich burn or EQ of 1.

    Its labelled a smoke limiter map because it is the main limiter the computer uses for fuel before boost, however it is still a limiter and usually you need to raise it above 1 on the upper end of the map to get full fuel. Usually I set it to "2" and smooth down to below one where you actually want it to restrict fuel for smoke reasons.