Gearing?

Discussion in 'Fiesta ST Engine Upgrades' started by Ataru, Sep 6, 2013.

  1. covert1

    covert1 New Member

    The FiST gearing has been in the back of my head for a couple of days, and thanks to this and another thread in the Auto-X section, I was compelled to do a little bit of digging. I have located various documents that mention the existence of the following final drive ratios for the Durashift B6 6-Sp Manual:
    3.611
    3.82
    4.07
    4.27

    As such, I decided to visit http://www.tremec.com/calculadora.php and do a side-by-side comparison of all the variants. Also, I apologize in advance for any typos - I was doing this without beer, and, I noticed that some of the information was possibly backwards or odd (more on that later). Here are the tables:

    1) Default gearing configurations for the different B6's I found

    B6comp_all.jpg

    2) Comparison of each with FDR of 3.611

    B6comp36fdr.jpg

    3) Comparison of each with FDR of 3.82

    B6comp38fdr.jpg

    4) Comparison of each with FDR of 4.07

    B6comp407fdr.jpg

    5) Comparison of each with FDR of 4.27

    B6comp427fdr.jpg

    Oddities / misc:
    According to the US 2014 Fiesta ST Supplement, as well as a US Technical Spec, the gears and FDR are exactly as I entered for the US FiST, with 2nd gear notably 2.098. The Ford EU Fiesta Technical Spec lists the exact same 1-6 gearing (2nd gear 2.048) that I found in the tech spec for the 2013 Fusion with 1.6L Ecoboost. The document with the Tourneo specs listed the ratios for 4th-6th as: 0.78, 0.844, and 0.683, respectively, so I reversed those to what I thought was the logical order.

    From a 2012 document, the C-MAX 1.0L Ecoboost B6 has the same gearing as the Euro FiST / Fusion 1.6L Ecoboost, but with the 4.27 FDR. Additionally, an overseas variant of the 2014 Fiesta 1.0L Ecoboost is said to have this gearing, but with the 4.07 FDR. So, the possibility is there for a USA Fiesta 1.0L owner to experiment with a transmission swap.

    I'm no expert, but I'm lead to believe that the available final drive gears and/or entire gear sets would swap just like they did on the MTX-75's did/do for the Focus / Contour.
     
    Last edited: Nov 13, 2013
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  3. wash

    wash Active Member

    I think the first thing I'll try is raising the rev limit and maybe a taller tire (but I don't want to raise the cg).

    I know Mountune is "developing" a close ratio gear set which probably means putting together a gear set using off the shelf Getrag parts from the various versions but might include gears that are special order or something.

    Any way, if I could get the second gear from the Tourneo Connect, a 4.07 final drive, fool the computer in to allowing over boost in second gear and raise the rev limit to 7,000 that would be about right. Maybe throw in a Quaife while the tranny is open? The Focus 3'rd gear might be tempting too.
     
  4. covert1

    covert1 New Member

    At the very least, I hope someone will attempt to procure the foreign parts. I have a hunch that many soon-to-be 1.0L enthusiasts are going to be considering a swap.

    Anyhow, for the hell of it, I put your inputs on that page... (by accident I found that the forum software would let me cut and paste pics into the reply window, which is awesome!) 7k RPM, 4.07 FDR, Torneo (Connect?) 2nd gear, Focus 3rd gear

    upload_2013-11-14_0-24-59.png
     
  5. wash

    wash Active Member

    Yeah, that seems pretty ideal to me. Good for 0-60 without a shift to third and more top end for second gear autocross. 1/4 mile times might be better if you can finish in third, the MPH would probably be rev limited but you could swap to 3.82 if your engine can pull it well.

    If there is a way to get over boost in second and Cobb comes through with a two-step launch control, I think an ST could do a lot better than the published acceleration times. If I can manage the turbo upgrade I've been thinking about and a set of sticky tires, deep 13's could be a reality.
     
  6. MJL

    MJL New Member

    Thank you, Covert1, that is the best information I could find on the web!
     
  7. raamaudio

    raamaudio Active Member

    If anybody wants to put it into the calculator my DHM tuned redline is at 7400, hard limit is 7700 in the ECU which I may go to.

    0-60 times in two gears will be much faster than in 3 gears, likely a marketing thing they did;)
     
  8. raamaudio

    raamaudio Active Member

    Gearing calculator shows with my 23" diameter tires, 7400 RPM redline, 63.18 MPH in second gear.
    There is a hard limit at 7,700 RPM in the Ford tune, some want to see what 8,000 RPM does to the engine, I would love to have that and be safe:)
     

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