Help me with A833 Gear ratio choice wide or close!

Manual Transmission & Clutch Discussions

  1. Brandt Fonda

    Brandt Fonda Well-Known Member

    Messages:
    48
    Likes Received:
    5
    Joined:
    Sep 11, 2017
    Location:
    NC
    Local Time:
    3:54 PM
    Got Jamie Passon buiding an A833 for me and I think I want the close ratio transmission but reading on some of the discussions on here I am now worried that the 2.47 first will be too high and the car may be a dog off the line.
    Current set up im working on is: 3.91 rear gears, 360LA bored 40 over, forged 9.5 pistons (adding 150 nitrous near future). Cam: Hughes Engines , roller rockers, 308 heads 2.02's with some mild porting, M1 dual plane intake, TTI 1-3/4 headers and holley sniper efi. Currently have 26" tall tires and probably will go with 27" in future.

    opinions on close or standard gear set with this combo? Plan on using the car mostly on the street but I don't care about "street manners" at the same time would like to be able to launch it with out burning up the clutch or bogging.
     
  2. yellow rose

    yellow rose Doctor of Thinkology.

    Messages:
    22,067
    Likes Received:
    18133
    Joined:
    Jun 19, 2015
    Location:
    Living on the razors edge
    Local Time:
    12:54 PM
    No way I’d put that first gear in anything. Close ratio sounds good, but it’s not for most stuff.

    I don’t know what Passon has for gear sets, but I’d see if he has something with a 3.XX first gear and leave the biggest gear split going into 4th.
     
  3. Brandt Fonda

    Brandt Fonda Well-Known Member

    Messages:
    48
    Likes Received:
    5
    Joined:
    Sep 11, 2017
    Location:
    NC
    Local Time:
    3:54 PM
    I had a 3.09 first in my OD trans and with the 3.91 rears it was pretty short and usually just burnt the tires.....but with 27"+ tires maybe?
     
    • Agree Agree x 1
    • 67Dart273

      67Dart273 FABO Gold Member FABO Gold Member

      Messages:
      42,931
      Likes Received:
      10502
      Joined:
      Oct 14, 2010
      Location:
      Idaho
      Local Time:
      12:54 PM
      I always figgured the 3x 1st was weak

      Way back in last century, about 73ish, I swapped a low miles 340 into what was an otherwise '70 RR 440-6 car. Used the 18spline box factory, in the car. I don't remember thinking "it was a dog." That car weighed about 3860lbs, and had the 3.54 (Dana 60) gear. It ran about 3K RPM at 70 mph with G60x15 tires
       
    • cryplydog

      cryplydog Member

      Messages:
      18
      Likes Received:
      1
      Joined:
      Aug 14, 2013
      Location:
      ewing, mo.
      Local Time:
      2:54 PM
      I can't imagine coming out of the hole wide open with a 3.09 first and then trying to hit a 1.92 second gear with any combo, that's a 1.18 drop between the 1st and 2nd. WOW. all other A833's have a 2.66, 2.65, 2.47,AAR/TA, and2.44 first gear. I know they sell boxes and talk up the 3.09 and I just can't see what they are wanting to accomplish performance wise. I use a regular 18 spline and a 23 spline and gear the axle for what I am wanting to accomplish. Then there is tire diameter also. good luck
       
    • RustyRatRod

      RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

      Messages:
      60,785
      Likes Received:
      32439
      Joined:
      Jun 7, 2010
      Location:
      Georgia
      Local Time:
      3:54 PM
      Good luck dealing with Passon.
       
      • Thanks! Thanks! x 1
      • ChargerST

        ChargerST Well-Known Member

        Messages:
        45
        Likes Received:
        6
        Joined:
        Dec 7, 2011
        Location:
        Austria
        Local Time:
        2:54 PM
        iirc Direct Connection recommended the 3.09 first 1:1 fourth gear set for drag racing. The 1.18 drop sounds huge but it's the percentage drop that matters: rpms drop by 38% (6000 --> 3728 rpm when shifting from first to second gear).
        When using a 2.66 first box the drop is 28% (6000 --> 4330 rpm). A difference of roughly 600rpm between both gear sets.
         
        • Agree Agree x 1
        • yellow rose

          yellow rose Doctor of Thinkology.

          Messages:
          22,067
          Likes Received:
          18133
          Joined:
          Jun 19, 2015
          Location:
          Living on the razors edge
          Local Time:
          12:54 PM

          I did it. Still do it. Lots of guys did it.

          The big deal is getting the car moving. I have a 14:1 overall first gear and it’s not quite low enough yet.

          With my drag car the best 60 foot and ET came with a 3.09 box. And that was a bit over 17:1 in low gear. You have to get the car moving.

          Also you’ll notice I said to see if Passon has a gear set that puts the split going into high gear. It’s better if you can do it that way, but someone has to make the gear set.
           
        • weedburner

          weedburner Well-Known Member

          Messages:
          176
          Likes Received:
          167
          Joined:
          Oct 20, 2015
          Location:
          Wa State
          Local Time:
          12:54 PM
          My 'tamer customers are trending to less 1st gear. Before the 'tamer, wheelspeed launches with a 3.30 1st gear was the sweet spot for the sealed engine guys (10.1@130 3100lbs). A few years later with basically the same power and the 'tamer controlling the clutch hit, dead hook launches with a 2.93 1st gear is in favor. The drops between 1/2 in both gearsets is about the same, but on the 2/3 and 3/4 with the 2.93 set they pick up about 300rpm. Ideal for the class looks to be around 2.75, but 2.93 is the closest rules allow for the G101a.

          Here's a graph of what those dead hook 'tamer launches look like with the 2.93. Clutch is locking up about .848sec into the run, 1/2 shift is out past the 60'. Notice how far out it carries the G peak, you get a smoother hit that lasts much longer...

          proper tamer launch with 4 turns.PNG

          Grant
           
        • yellow rose

          yellow rose Doctor of Thinkology.

          Messages:
          22,067
          Likes Received:
          18133
          Joined:
          Jun 19, 2015
          Location:
          Living on the razors edge
          Local Time:
          12:54 PM
          They are trending down, but still much steeper than the 2.44 or 2.66 gears available to these guys.

          BTW, how much rear gear are these guys using?
           
        • weedburner

          weedburner Well-Known Member

          Messages:
          176
          Likes Received:
          167
          Joined:
          Oct 20, 2015
          Location:
          Wa State
          Local Time:
          12:54 PM
          4.56 / 4.30, naturally aspirated 302ci running at 3100lbs.

          Grant
           
          • Thanks! Thanks! x 1
          • cryplydog

            cryplydog Member

            Messages:
            18
            Likes Received:
            1
            Joined:
            Aug 14, 2013
            Location:
            ewing, mo.
            Local Time:
            2:54 PM
            Yellow Rose, I agree that their isn't a gear set to maximize the use of the 3.09. the 1-2 syncros have a tough job anyway. I have an aluminum 3.09 box that was in my 64 polara w/ a 440 and it worked ok but I changed it out because it just wasn't for me I guess 4:10 Dana.
             
          • vntned

            vntned Well-Known Member

            Messages:
            1,225
            Likes Received:
            758
            Joined:
            Apr 28, 2012
            Location:
            Gibsonville NC
            Local Time:
            3:54 PM
            I'd go 2.66 first. 3.09 first with 3.91s in the back and it'll be a smoke show in first gear without some real rubber.
             
          • gzig5

            gzig5 Well-Known Member

            Messages:
            1,193
            Likes Received:
            1135
            Joined:
            May 3, 2018
            Location:
            Mequon, WI
            Local Time:
            2:54 PM
            I think the car weight has a lot to do with it. The early B-body 833's had the 3.09 first and I'm sure they did it to help get the big bastards moving. It's even more important if your motor isn't especially torquey. The Getrag six speed I have in one car has a 4.23:1 first gear with 3.45 rear, and though it is about done by 30mph that 4000lb car comes out of the hole like nobodies business. I wouldn't be afraid to run a 3.09 and actually have an 833OD and 2.66 standard to choose from when I get to the swap in a year or two.
             
          • Brandt Fonda

            Brandt Fonda Well-Known Member

            Messages:
            48
            Likes Received:
            5
            Joined:
            Sep 11, 2017
            Location:
            NC
            Local Time:
            3:54 PM
            My first instinct is to get away from those 3.09 gears since I plan on using the car 99% of the time on the street, and I've had traction issues as I have not done spring relocation. My real attraction to the 2.47 is that close ratio gearset, seems like it would really be a blast around the curves we have up here in the Mountains. But I know if I'm at the red light and I get in a little spirited competition I want to get the car moving! 2.66 gearset seems to be the compromise between the 2... and need to check into one of those tamers.
             
          • Brandt Fonda

            Brandt Fonda Well-Known Member

            Messages:
            48
            Likes Received:
            5
            Joined:
            Sep 11, 2017
            Location:
            NC
            Local Time:
            3:54 PM
            I personally did not like the OD I had. Burn tires when u take off, and by 3rd your already at 1:1 in 2 shifts then .73 your not going anywhere fast. Only pro is the cruising gear.
             
            • Agree Agree x 1
            • gzig5

              gzig5 Well-Known Member

              Messages:
              1,193
              Likes Received:
              1135
              Joined:
              May 3, 2018
              Location:
              Mequon, WI
              Local Time:
              2:54 PM
              If I do the OD it will be behind a 408 stroker and with 500lb+ of torque available most of the way through the range, the big gear spread shouldn't be that bad. Who knows, still a long ways off but I do have the parts and by then I should have the time to experiment.
               
            • AJ/FormS

              AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

              Messages:
              18,239
              Likes Received:
              6477
              Joined:
              Jan 19, 2014
              Location:
              South-Central Manitoba,Canada, 900ftelevation
              Local Time:
              2:54 PM
              For a streeter
              thirty-ish mph is where it's at. First gear with 3.91s and a 360 will be a smoke show no matter what, So do what you can
              For instance; if most of your street driving is gonna be say 30 to 40 mph, then you are gonna need some juice at those speeds. If you built your engine for torque, then the peak will be around 3800, so you want to be at 3800 going into 30 mph. That would take an overall gear ratio of 10.19 with 27" tires.
              With 3.91s that would be a 2.66 low gear
              with 3.23s you could use the 3.09 box
              with 4.10s you could use the 2.47 low.

              At the other end you gotta deal with the Rs at cruising speed. At 65 mph;
              3.91s will cruise at 3161
              3.23s at 2610
              4.10s at 3310

              And finally, how about your second gear cruising rpm at 30 mph.
              With a 1.92 second gear;
              3.91s at 2800
              3.23s at 2311
              4.10s at 2930
              With a 1.77 second gear;
              3.91s at 2580
              3.23s at 2130
              4.10s at 2700

              I use the ones in blue, because;
              I can be cruising at 30 mph@2311 rpm ; I am Mr. nonchalant, all quiet and sneaking around.
              But when I espy a buddy, I sneak up on him and with a flick of the wrist, I am in low gear at 3720 and my car explodes into a maelstrom of thunder, lightning and smoke, and she is g-o-n-e.
              Yet she cruises 65=2311
              So in conclusion;
              I have run every fine-spline Mopar 4-speed there is, and with nearly every rear gear from 2.76 to 5.38s, and this is my favorite combo for a 223*@.050 cam.

              I currently run a 230* cam and it likes 3.55s.
              Does my 360 need a 3.09low? Probably not, but with a 3.55 rear gear, that 3.09 is a winner. My 360 does not notice the 1-2 split.......... because at WOT;
              it burns right thru first,
              and right thru second,
              and sometimes to 85 mph, still in second gear.

              If your 360 has some oats at 3400, You will not be sorry with the 3.09 low, and you will be swapping out those 3.91s in no time.
              Besides, you can do what I do; just rev first gear to 6400 and let her drop into second at 4000, shazzam!
               
              • Like Like x 2
              • Brandt Fonda

                Brandt Fonda Well-Known Member

                Messages:
                48
                Likes Received:
                5
                Joined:
                Sep 11, 2017
                Location:
                NC
                Local Time:
                3:54 PM
                Thanks for all the input, I went with the 2.66 hopefully with my 3.91's it will be a good combo!
                 
                • Agree Agree x 1
                • vntned

                  vntned Well-Known Member

                  Messages:
                  1,225
                  Likes Received:
                  758
                  Joined:
                  Apr 28, 2012
                  Location:
                  Gibsonville NC
                  Local Time:
                  3:54 PM
                  Good call!
                   
                  • Like Like x 1
                  • Agree Agree x 1
                  1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                    By continuing to use this site, you are consenting to our use of cookies.