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4.09 or 4.11

Discussion in '2015+ Shelby GT350 Mustang' started by ANGREY, Dec 27, 2018.

  1. ANGREY

    ANGREY Active Member Established Member

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    I'd go bigger gear if they made a lower 6th gear for the 3160. 390's wasn't worth the hassle and 4.30's seemed a little crazy without lowering 6th. I'd love a .50 6th gear option to compliment a set of 4.30's.

    On a side note, long trip from Tampa to Miami yesterday and did a 4th gear drop and rolled the tires over (with the stock 3.73s) in the rain. And that's with 325's out back. These cars have torque, you just have to be in the proper rpm/gear to wake it up.
     
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  2. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    Anything above 4K rpm is gravy zone for the voodoo mills.

    I fooled around in a gt350 for 20 minutes and it had plenty enough torque for city duty at 5000ft. It got up to 100 plenty fast. I kept wishing the gearing was like a quarter shorter though. I was getting almost 90 from 2nd. My stock 03 cobra with 3.55’s had shorter gearing to give an idea but obviously it only revved to 6500. I like the spread on the v8 bmw e92’s and love the spread in b7 rs4’s. Getting 3rd to reach 100 at roughly redline is a nice spread imo for a fun peppy Street car. Stock Gt350’s were running 110+up here, the mill has legs. I think a 4.56 gt350 could hit 112-113 by being up on average power during a quarter mile run up here, maybe 120 at sea level for the same reasons.

    I think 4.56 might be too much for a sea level car, up here stock c6z’s trap 112-115 to give an idea. Auto. Hellcats can’t break 120 stock on perfect nights.

    When daily driving though, 2500-3k on the freeway is erksome. I think 4.09/4.11 is a great gear for a daily driver
     
    Last edited: Jan 28, 2019
  3. ANGREY

    ANGREY Active Member Established Member

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    Car went in for surgery this a.m. She's under the knife as we speak. Will report back as soon as she's in recovery.
     
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  4. 662

    662 Active Member Established Member

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    Excellent. My dream recipe is a gear and Proflex E85 Commander with JLT intake.

    Actually 538rwhp is the ultimate dream, but that's a lot of surgery...
     
  5. mjc1241

    mjc1241 New Member Established Member

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    Probably going to do a 4.09 gear this year at some point but I already have a PMAS intake and Proflex Commander installed. More than sixty pounds of weight reduction as well with a CF driveshaft, lightweight battery, catless mids, stock resonator and x pipe replaced with Shiftek H pipe, Fathouse Fabrications lightweight battery, which are already installed; along with P51 R Spec wheels with Conti Extreme 305/30/19 front and 325/30/19 rear tires, which are to be installed next month. Car should feel much lighter on its feet because it already runs strong with the CF driveshaft on E85 with the Proflex Commander, PMS no tune intake and catless mids. The gear should give it the right kick in the nuts to get in angry at lower rpm.
     
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  6. ANGREY

    ANGREY Active Member Established Member

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    IMG-20190208-WA0004.jpg IMG-20190208-WA0004.jpg IMG-20190208-WA0005.jpg Picked up the car, didn't get a chance to flog it. Even though US Gear claims there's no break in period with their Isotropic Super Finish, probably for the best that I drive it a bit and let it wear in. Other gears came out and were in nearly perfect shape. Installer actually sent me photos of the pattern and a video of the backlash (incredibly professional). Just from "normal" city stoplight driving I could tell a little bit of a difference, especially in 1st gear standing starts.
     
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  7. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    Congrats, this should be the factory rear imo
     
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  8. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    I’m held together with whisky, cheap sex and my mullets matching jerry curl so I want to see what a 4.56 does for these cars.
     
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  9. DSG2003SVT

    DSG2003SVT Gray only, please Established Member

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    ~4.09 would likely be the ideal gear for this car in my estimation too. So, I look forward to your thoughts.


    Sent from my iPhone using Tapatalk
     
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  10. ANGREY

    ANGREY Active Member Established Member

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    Had a chance to run it out a few times.

    If I use the headers/exhaust 93 tune as the first "stage" and the E-85 as the second stage, and the 4.09s as the 3rd,

    The gears "feel" to be the biggest difference. Much less of the low rpm psudo turbo lag. Runs up the redline and shift drop at a tempo more like the old 6800 redline cars (even though it's blasting to 8k+)
     
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  11. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    Nice, any more feedback?
     
  12. biminiLX

    biminiLX never stock Established Member

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    Great mod.
    -J
     
  13. ANGREY

    ANGREY Active Member Established Member

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    It's tough because I didn't do them in a "control" type environment where it was the gears and nothing else.

    The E-85 made a very noticeable difference in how ready the car is to respond in mid to lower rpms. With my N-guage display, I'm running MUCH higher timing in the mid to lower rpms than before, so the car is more "woke" (hate that term) and ready and willing to lay it down.

    Once I put the gears on, it was even more pronounced of a feel/effect. 10% artificial torque at all rpms isn't trivial. Imagine having 35-40 more lb-ft of engine torque at 3k rpms and every range above.

    I did a cruise to Palm Beach cars and coffee on Sunday and was at the back of the pack and getting on I-95 I went to do a 4th gear dump and the rear got squirrely a little (just wagged, no real problem) and I was a little surprised. Also, rowing through the gears now takes on a more "traditional" cadence. Before, it was always the run up and then that extra long breath that GT350 guys learn to wait for. But now it screams through them at a rhythm I'm more accustomed to on the older 6800 limit motors.

    This is an expensive modification. $340 for gears and nearly $800 after parts/installation (installation kit, new pinion race, fluids, labor). Finding anyone to do a Super 8.8 for cheap is impossible. Most shops have never even done the swap. So it's not a cheap modification or something that's quick. But it is high value in terms of effect for $ spent.

    If I'd have known then what I know now, I'd have probably done the gears before I did a lot of other stuff.
     
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  14. ANGREY

    ANGREY Active Member Established Member

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    Just to give everyone a perspective, with the ratio on the 3160 vs. the MT in the GT's, this basically washes away the gearing gap and is approximately the equivalent of running 3.73's in a Mustang GT (manual).

    4.09 seems a little extreme until you realize just how tall our transmission ratios are.
     
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  15. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    I agree with everything you said. I ran 4.10’s in my 03 cobra with t56 spread and 6500rpm, it was too much gear for a full bolt on car.

    I’m running 3.73’s now with t56 ratios but 8k rpm.
     
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  16. JJ510

    JJ510 New Member

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    I'm also looking to do a lower gear in my 18 350. I think 4.30's would be perfect but they are not available. I'm not convinced that the 4.09 will be that much of a difference. I remember going from a 3.73 to a 4.10 on a 91 Notch back in the day and it wasn't that much different. And that was on a car that didn't rev over 6k. With the 350's 8200 redline I think it will be even less noticeable. There was an excellent write up on another forum of a guy that did 4.56's but he didn't give much feedback on the actual results. I would love to see a video of a pull before and after a gear change.
     
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  17. tt335ci03cobra

    tt335ci03cobra Well-Known Member Established Member

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    If you go 4.56 and it’s awful, I’d feel guilty to say this, but if I were you I’d go 4.56 @JJ510
     
  18. biminiLX

    biminiLX never stock Established Member

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    4.56 street and strip, but that’s not a great idea. 4.09s and a twin kit with E85 should roll out hard on the road.
    -J
     
  19. ANGREY

    ANGREY Active Member Established Member

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    You're comparing apples to oranges. It's noticeable because of the torque/power band on the voodoo. Even a 10% difference (say a 20 to 40 rwtq) is felt, most noticeably at lower rpms where even small amounts of artificial torque change the character of the car.

    Just starting from a stoplight is completely different now. You can go 4.56 and it's gonna wake it up even further, but it's going to be felt much much more negatively on the rpm cruising.
     
  20. JJ510

    JJ510 New Member

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    Any chance of you putting up a short vid of your tach while doing a quick 1st to 3rd gear pull?
     

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