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Thread: 2014 Dodge R/T - Differential Change - 2.65 TO 3.09 - Basic Tuning Questions

  1. #1
    Tuner in Training
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    2014 Dodge R/T - Differential Change - 2.65 TO 3.09 - Basic Tuning Questions

    Hello,

    Thanks to all who spend any time helping, in advance.

    I'm getting ready to do a rear end swap to the 3.09 differential, however in the tune file I do not see where the differential can be changed.

    Will I need to adjust each and every gear ratio to account for the differential change ? Or do I just need to adjust the shift tables by the % of different in the new rear ratio causing the output shaft to spin faster ?

    Sorry, I primarily tune on the GM side and the dodge ecm's seem much different.

    Thanks again

  2. #2
    Advanced Tuner coanan's Avatar
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    Don't touch the trans gear ratio, change rear ratio/tire size in scanner. Shift tables, don't know, but my auto down shift is off since I went with the 3.73, but I have a valve body, torque converter, trans job. I also lost my ACC/FCW cause HPTuner doesn't map far enough into the system. They say Diablo fixes this.
    2018 Trackhawk PCM/TCM tune by Dusterhoff.
    Flex Fuel, MMX faux 95mm TB, GripTec 2.85, 10% ATI lower, FIC1200, ARH 1 7/8 w/cats, 180 T-stat

    13 Chrysler 300S, RAM BGE 412 stroker, cam motion 232/246 619/619 118 +4, ATI 18% OD pulley
    Whipple Gen5 3.0, 2.50 upper pulley, Smooth Boost controller, FIC 1200 inj. Nick W 108mm TB, FORE dual return fuel system, E85, FTI 2800 stall(SRT83380), SHR WAR Viking trans and valve body, Getrag 3.73, 1 7/8 kooks w/hi-flow cats, 3" Magnaflow Cat-back 943rwhp

  3. #3
    Tuner in Training
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    Quote Originally Posted by coanan View Post
    Don't touch the trans gear ratio, change rear ratio/tire size in scanner. Shift tables, don't know, but my auto down shift is off since I went with the 3.73, but I have a valve body, torque converter, trans job. I also lost my ACC/FCW cause HPTuner doesn't map far enough into the system. They say Diablo fixes this.

    Hey Coanan, thanks for the reply. I'm not sure what you mean with, "Fix in scanner", I'm assuming the scanner will have an added ability I'm not used to on GM's when connected to a dodge ?

    My understanding of the scanner is, VCM Scanner for datalogging.

    Thanks in advance.

  4. #4
    Advanced Tuner coanan's Avatar
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    Quote Originally Posted by x2xplaguex2x View Post
    Hey Coanan, thanks for the reply. I'm not sure what you mean with, "Fix in scanner", I'm assuming the scanner will have an added ability I'm not used to on GM's when connected to a dodge ?

    My understanding of the scanner is, VCM Scanner for datalogging.

    Thanks in advance.
    connect to vehicle, Open scanner, next to eng pic is a yellow button, click, it's in there.
    2018 Trackhawk PCM/TCM tune by Dusterhoff.
    Flex Fuel, MMX faux 95mm TB, GripTec 2.85, 10% ATI lower, FIC1200, ARH 1 7/8 w/cats, 180 T-stat

    13 Chrysler 300S, RAM BGE 412 stroker, cam motion 232/246 619/619 118 +4, ATI 18% OD pulley
    Whipple Gen5 3.0, 2.50 upper pulley, Smooth Boost controller, FIC 1200 inj. Nick W 108mm TB, FORE dual return fuel system, E85, FTI 2800 stall(SRT83380), SHR WAR Viking trans and valve body, Getrag 3.73, 1 7/8 kooks w/hi-flow cats, 3" Magnaflow Cat-back 943rwhp

  5. #5
    I tried calibrating tires last night at the track before we left. Cousin's 2017 ram we just tuned on 24s. Needless to say the mph will go blank. Set the tire size back to stock. After about 20 minutes of driving the ECM relearns what the vss is reading on trans and resets itself. Don't freakout if it does that to you.

    It said auto park disabled and the power steering was out until we ran it for a while as i assumed it would relearn. thank goodness...

    Now even with stock tire size settings.. its reading proper mph.