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What gear ratios manual trans?

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  • What gear ratios manual trans?

    This combination has not been run yet so I don't have any info other than theory. Heavy car, 572 BBC 4.11 rear. 2,98 first 2.06 2nd, or 3.18, 2.20 with the mandated 11.25 tire for SS BB NA, HRS dual disc iron clutch. Thanks

  • #2
    when you figure it out , let me know! x2 heavy car, small BBC, 4.11s ( open for change)
    Reading , Pa
    Good Guys rodders rep.
    "putting the seat down is women's work" Archie Bunker.
    Ban low performance drivers not high performance cars .

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    • #3
      I may not be much help, but I have always looked at what your 60 expectations are compared to how hard you want to beat on it and how streetable you want it.

      One thing to make sure about is the ability to not bog the motor yet still be able to shift it on time. Seen some manual trans cars that were geared to the point that first was slowing 60 down based on the launch and shift. Less gear actually dropped ET since it was controlable and allowed the torque of the motor to rpm through the range.

      Hope that makes sense? Same deal with dropping final drive gear and car picks up. Sometimes less gear is better.

      My junk is going to be 2.52, 1.88, with a tiny small block and at most 3.73 gear. But I am not going for all out ET in a heads up class.
      -Bobby-

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      • #4
        Mike Crow has been working on some of this and so far the more gear has been better with the Old Cuda. He is finding the same with his new car too.
        2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
        First to run in the .90s .80s and .70's in SBN/A
        2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
        2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

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        • #5
          The steeper gear set will get the weight moving easier/quicker

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          • #6
            Originally posted by aukai View Post
            This combination has not been run yet so I don't have any info other than theory. Heavy car, 572 BBC 4.11 rear. 2,98 first 2.06 2nd, or 3.18, 2.20 with the mandated 11.25 tire for SS BB NA, HRS dual disc iron clutch. Thanks
            Jeff is right I have been running a 3.5 rear and a 1st gear of 3.76 for an overall ratio of 13.16 This year I have changed the rear gear to 3.70, trying to get the car to 60 ft better. With the size of your motor you are going to make alot more torque than I am making, you might be ok with that overall gear ratio. What trans are you running? My concern is will the Transmission handle the HP you are putting to it.

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            • #7
              It probably goes without saying, but make you take into account your tire height too.
              '91 Trans Am GTA: 402ci LS2, faceplated T56, 9", and nitrous.
              2013 Drag Week SURVIVOR! - SR/SB/PA & 2014 Drag Week SURVIVOR! - SR/SB/NA

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              • #8
                Originally posted by 73fish View Post
                Jeff is right I have been running a 3.5 rear and a 1st gear of 3.76 for an overall ratio of 13.16 This year I have changed the rear gear to 3.70, trying to get the car to 60 ft better. With the size of your motor you are going to make alot more torque than I am making, you might be ok with that overall gear ratio. What trans are you running? My concern is will the Transmission handle the HP you are putting to it.
                Mike I understand what your saying, but can you get to a point of " too much gear" . I been talking to liberty and g-force, they say Im above the safe margin with a built TKO, and that a dead hook will probably hurt it. they say a t56 is an option....but if I step up the power, I will be on the edge. the lsc5000 is an option, as I may put more power in it in the future.
                Reading , Pa
                Good Guys rodders rep.
                "putting the seat down is women's work" Archie Bunker.
                Ban low performance drivers not high performance cars .

                Comment


                • #9
                  Originally posted by ls7gto View Post
                  Mike I understand what your saying, but can you get to a point of " too much gear" . I been talking to liberty and g-force, they say Im above the safe margin with a built TKO, and that a dead hook will probably hurt it. they say a t56 is an option....but if I step up the power, I will be on the edge. the lsc5000 is an option, as I may put more power in it in the future.
                  I have also heard that and I have been all the way down to 2.93 1st with a 3.5 rear gear and the 60 ft's fell off, so far the best I have been is 1.52 with 3.76 1st and the 3.5 rear gear, thats in the Cuda at 3695 Lbs with the 10.5 ET Streets. The Dart last year was down to 1.47 60 ft's with the 3.5 rear gear it now has the 3.7's in it. As soon as I get to the track back to the track I will keep you posted.

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                  • #10
                    Hey guys, thanks for the input. Spent the day working on the car, I posted earlier, but I guess I didn't push the post button. I have a GF-5r that Bubba set up with a 2.98 first to make sure the clutch was going to slip, he may not have done me any favors. Tim want's the 3.18, 2.20, 400 bucks a gear set. Would a rear gear change make a diff? 4.33x2.98 would be 12.90....4.44x2.98 13.23. Highway RPM may suffer. It's looking like 30" tires will be what I'm going with.
                    Last edited by aukai; April 4, 2013, 11:45 PM.

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                    • #11
                      Originally posted by aukai View Post
                      Hey guys, thanks for the input. Spent the day working on the car, I posted earlier, but I guess I didn't push the post button. I have a GF-5r that Bubba set up with a 2.98 first to make sure the clutch was going to slip, he may not have done me any favors. Tim want's the 3.18, 2.20, 400 bucks a gear set. Would a rear gear change make a diff? 4.33x2.98 would be 12.90....4.44x2.98 13.23. Highway RPM may suffer. It's looking like 30" tires will be what I'm going with.
                      Your still gonna have 1:1 in high gear unless you run OD... so even if you go to
                      the steeper low gears in the trans it wouldnt change the e-way rpm

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                      • #12
                        Originally posted by aukai View Post
                        Hey guys, thanks for the input. Spent the day working on the car, I posted earlier, but I guess I didn't push the post button. I have a GF-5r that Bubba set up with a 2.98 first to make sure the clutch was going to slip, he may not have done me any favors. Tim want's the 3.18, 2.20, 400 bucks a gear set. Would a rear gear change make a diff? 4.33x2.98 would be 12.90....4.44x2.98 13.23. Highway RPM may suffer. It's looking like 30" tires will be what I'm going with.
                        My first choice would be the 3.18, 2.20 but I understand the cost of the gearsets. If you change the rear gear to 4.33 and 30" tire at 65 mph is 3153 RPM, what kind of RPM would you like to turn it running down the road?

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                        • #13
                          Originally posted by ls7gto View Post
                          Mike I understand what your saying, but can you get to a point of " too much gear" . I been talking to liberty and g-force, they say Im above the safe margin with a built TKO, and that a dead hook will probably hurt it. they say a t56 is an option....but if I step up the power, I will be on the edge. the lsc5000 is an option, as I may put more power in it in the future.
                          I agree with them, the G5R and LSC5000 will handle alot more power than the T56 and The TKO.

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                          • #14
                            Originally posted by MR P-BODY View Post
                            The steeper gear set will get the weight moving easier/quicker
                            With this in mind, 4.11 would be better than 3.73 as far as dependability?
                            Don't mean to steel the thread, but I have both sitting on the shelf and am trying to decide on which one to go with. And gas mileage is shot anyway, and I seldom go over 70 on the road.
                            Drag Week 2012 (wet paint and no transmission but finished) Drag Week 2013 Daily Driver finished in middle of pack (again) Drag Week 2014 #56 of 126 Daily Drivers. (getting closer to the 32)

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                            • #15
                              Its a toss, the 3.73 might dead hook, the 4.11 might have to small a pinion teeth count.
                              2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                              First to run in the .90s .80s and .70's in SBN/A
                              2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                              2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

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