3.07, 3.09, 3.90, & 3.92 Diffs

Discussion in 'SRT Hellcat Performance' started by sinister707, Jan 3, 2016.

  1. sinister707

    sinister707 Silver Member

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  2. ReoTom

    ReoTom Silver Member

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    Why would you change the differential gearing? Can't get traction now? It's geared perfect ! Somethings are best left alone. JMHO... :D:D:D
     
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  3. sinister707

    sinister707 Silver Member

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    (remember i'm a rookie ;) )

    definitely valid points... i was considering the 3.09 just to have a slight "upgrade" in "initial" acceleration but i might go down to the 3.07... I have an A8 and thinking about using my car (as crazy as this is going to sound) as a road course/autocross car. i think i have a 2.62 stock and i think 3.07 would be a slight improvement and not over kill.

    I mentioned the others in the title because it seems that everyone is only talking about the 3.09 and may have not heard about the others.

    Plus I want to do some suspension upgrades as well to help put the rubber down.
     
  4. ReoTom

    ReoTom Silver Member

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    Gotta remember especially with the auto that all your computer settings and shift points are all programmed to mesh with the current differential gearing.. I don't know how much reprogramming it would take to mesh all your set drive modes.. I guess you could inquire with the tuning people.. sounds complex. Lol!
     
  5. DShatzer

    DShatzer Gold Member

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    Several people here are running 9.7 in the quarter with a stock suspension and 3.09 gears. More bite?
     
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  6. ReoTom

    ReoTom Silver Member

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    Yea... if your running drag slicks etc.. but if your auto crossing stock is still the best overall compromise.
     
  7. DShatzer

    DShatzer Gold Member

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    I was responding to Sinister's desire for "more bite". I would think for autocross, you would want a tricked out Abarth. Unless it is a drifting autocross....
     
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  8. ReoTom

    ReoTom Silver Member

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    That's what one guy on here was illuding too. Me I'm a drap strip / street racer guy... just love her the way she is.. plenty quick for me.. maybe one day will do a pulley tune mod and some street slicks.. about as far as I'll ever go.. o_O:D
     
  9. hellcat1

    hellcat1 Gold Member

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    I for one think the 3.09 or if they come out with a 3.55 is a mod I will be doing. I can get my car to hook up, plus at a roll that car will be a beast...with the A8 it really isn't going to hurt anything. Think of it this way, the M6 cars come with a 3.90 rear gear, and they have zero issues, if we went that route, it would be the same,, but we would have to extra gears on the top end...I think it's a great idea to change them out
     
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  10. graycat

    graycat Automobile Aficionado Extraordinaire Staff Member

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    I could be wrong but I believe that "all gears are not created equal" In other words some of the diff's are not intended for the added torque of the Hellcat. I think that some of the gear ratio diff's for sale are not as strong
    and not even a direct "bolt in" for our Hellcats.

    Again, I could be wrong on this, I haven't made a swap on one of these cars myself yet.
     
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  11. TNCHARGER

    TNCHARGER SRT Hellcat Supporter Gold Supporting Member

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    My understanding is the 3.09 and 3.70 are the only two diffs available for the Hell Cat. The others are Getrags made for the SRT & RT models... I installed the 3.09 and think it is perfect for street or quarter mile track. Any more gear and 1st will be useless street or track.
     
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  12. graycat

    graycat Automobile Aficionado Extraordinaire Staff Member

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    TNCHARGER....I'm 100% in agreement with you.
     
  13. ReoTom

    ReoTom Silver Member

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    The reason 6 spd. Come with a 3.90 diff. is that your missing 2 gears you don't have with manual vs. Auto. You need that differential to compensate for less gears.. but with auto it's best to stay stock unless you just want a 1/4 mile drag car.. JMHO...
     
  14. TNCHARGER

    TNCHARGER SRT Hellcat Supporter Gold Supporting Member

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    The 392 manual comes with the 3.90. The HC manual comes with a 3.70..
     
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  15. ReoTom

    ReoTom Silver Member

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    My Bad.. 3.70. :D
     

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