Selecting the Right Gear Ratio - Need Help 5.0 A6

Discussion in 'Mustang Chit Chat' started by Sigma6, Oct 15, 2020.

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  1. Sigma6

    Sigma6 Junior Member

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    That seems to be the consensus with the 05-10 models but this would be the first I’ve read /been told with the 11-14 autos. I am sorta all over this place in terms of what’s good vs overstated. I know 3.31 isn’t worth the cost and 4.10 are too steep but this is at least forward process. :)
     
    06 T-RED S/C GT likes this.
  2. Midlife Crises

    Midlife Crises Member

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    I’m not running an auto trans but if I had your setup and was going to change rear gears I’d go to 3.73s.
     
  3. Norm Peterson

    Norm Peterson corner barstool sitter

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    You sure about that?

    I keep finding 4.17 / 2.34 / 1.52 / 1.14 / 0.87 / 0.69 being the gear ratios for the 6R80. Even the 6R60 is supposed to be using those ratios.


    Norm
     
  4. Pentalab

    Pentalab forum member

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    Senior moment..again. You are correct.
     
  5. Sigma6

    Sigma6 Junior Member

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    Correct. It’s they 1st gear ratio as to why I don’t wanna go 4.1 or 3.73
     
  6. Grabber Blue 5.0

    Grabber Blue 5.0 forum member

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    Anything over a 3.55 is a complete waste and way too much gear. I would actually skip the gear and go with a converter. I ran low 11's N/A with my 3.15's.

    This is from personal experience with my 2011. Keep in mind many in this thread have no experience and they're just throwing out numbers. Not good.
     
    Pentalab likes this.
  7. Norm Peterson

    Norm Peterson corner barstool sitter

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    Not good if the person putting the numbers up simply reads them off of some internet link with no real understanding of how to use them or how to relate changes in gearing to actual driving without having to personally make and drive-test each and every one of them. Yeah, I'll give you that much.

    Just don't assume that means everybody. Not even everybody who isn't a drag racer.

    At least with the automatic you do have a torque converter option in most cases, and that did cross my mind earlier. One of the things I don't know there, is what's available for a street driven car that retains the lockup feature.


    Norm
     
    Last edited: Oct 17, 2020
  8. jewc75

    jewc75 forum member

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    All of the converters retain the lockup.
     
  9. Sky Render

    Sky Render Stig's Retarded Cousin S197 Team Member

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    What converter do you have?
     
  10. jewc75

    jewc75 forum member

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    Circle D 6F, had a 4C but had it restalled by them.
     
  11. MjlSRQ

    MjlSRQ Junior Member

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    I have a 14 Roush GT Convertible Stage 2 w/auto. I changed from 3.15 "comfort gear" to the 3.55s and its better but a year later I am looking to move up to 4.10s. The JMS pedalmax was the best mod I ever did for the car (I have the Ford PMS & CAI with GT 500 Cat back for the tune)
     
  12. 06 T-RED S/C GT

    06 T-RED S/C GT forum member

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    Your absolutely right! I'm in the consensus with the 05-10 models as an owner. Therefore, I stand corrected regarding the 11-14 autos. At any rate, from my own experience, I first upgraded from stock 3:55 gears to 4:10 but eventually went back to stock 3:55's as there was just way too much torque off the line, always spinning tire for which 1st gear was pretty much useless. Being that I mostly do highway driving and don't drag race nor take my car to the track, 3:55 gears are more than good enough with a supercharged application. That being said, I agree with the other posters who know from personal experience with the 11-14 autos that going above 3:55-3:73 gears is considered as overkill.
     
  13. Sigma6

    Sigma6 Junior Member

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    @MjlSRQ. How’d you like it.... how’d it handled from a stop/start standpoint? Any issues roasting the tires? How was highway driving (rpms etc etc) Can you fee a difference over 3.15? I’d appreciate some input from some as you have a 14 Auto GT :)
     
  14. Pentalab

    Pentalab forum member

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    On a similar note, my 2010 auto comes with a 3.31 rear gear. But my 2nd gear is 14% lower than 2nd gear in your manual. My 3rd gear is 16.5% lower than 3rd gear in your manual. In 4th, we are both 1:1 ratio. You would require a 3.73 rear gear to equal my 3.31 for 2nd gear. You would require a 3.90 rear gear..to equal my 3.31 for 3rd gear. That's why I left the oem 3.31 rear gear alone. Where I lose it is in 4th gear. Any 05-10 manual with a 3.55 /3.73 /3.90/4.10 is a lot quicker in 4th gear.

    With my small blower + LT's and 62mm tb + 94 tune, it's all I can safely handle (305 mpss rears). As is, it won't stay straight at the top end of 2nd gear..stupid fast by my meager standard.

    Auto's and a PD blower can be a handful. Mash the gas, it drops down gears, blower on, instant boost, then hang on for the ride.
    Sri for OT for the OP.
     
    06 T-RED S/C GT likes this.
  15. Sigma6

    Sigma6 Junior Member

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    This is good information. Swaying to leave it alone at this point. Thanks
     
    Grabber Blue 5.0 likes this.
  16. Pentalab

    Pentalab forum member

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    Another possible option..is to have it tuned for 91/93 octane. If it's on the oem stock tune, they have left a lot on the table. If you wanted more, LT's plus a 91/93 tune would be more than an eye opener. I'm biased though... I view folks who do these rear end gear swaps as a band aid solution for lack of tq/hp..esp low end tq. I added ceramic coated jba LT's..and hi flow catted H..and a new 94 tune...and it was a jaw dropper. The difference was blatantly obvious.
     
  17. Midlife Crises

    Midlife Crises Member

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    Did that really come out the way you meant it? One size fits all?
     
  18. jewc75

    jewc75 forum member

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    Or maybe you dont have enough hp to be fast enough to swap gearing. 3.15's are junk, 3.31's are what most sub 10 second cars run. Some sub 9 sec cars go the other way 2.73 gears. Its all about the combo and going with what works and has been proven to work. A street car id run 4.10's all day.
     
  19. Grabber Blue 5.0

    Grabber Blue 5.0 forum member

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    Yea no. 3.15’s are not junk. That’s just a foolish statement.
     
  20. jewc75

    jewc75 forum member

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    You are an idiot, crawl back into your moms basement.
     
    dark steed likes this.
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