M50/ZF with 2.79 final drive

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  • alexbaby88
    Wrencher
    • Feb 2005
    • 219

    #1

    M50/ZF with 2.79 final drive

    Anyone tried mating a 5sp ZF with 1:1 fifth with a 2.79 final drive? How does it affect acceleration in the lower gears? I have a stock 3.25 now and trying to get lower cruising RPMs (gearing calc shows 400rpm lower at 60mph) but obviously don't want to sacrifice too much in the first 4 gears.
  • nrubenstein
    No R3VLimiter
    • Feb 2009
    • 3148

    #2
    3.25 with an S50 is sluggish. 2.79 will be brutal. Save the money and get a 6-speed instead.
    2006 GMC Sierra 2500HD 4WD LBZ/Allison
    2002 BMW M3 Alpinweiß/Black
    1999 323i GTS2 Alpinweiß
    1995 M3 Dakargelb/Black
    - S50B32/S6S420G/3.91
    1990 325is Brilliantrot/Tan
    1989 M3 Alpinweiß/Black

    Hers: 1996 Porsche 911 Turbo Black/Black
    Hers: 1988 325iX Coupe Diamantschwartz/Black 5spd

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    • alexbaby88
      Wrencher
      • Feb 2005
      • 219

      #3
      Originally posted by nrubenstein
      3.25 with an S50 is sluggish. 2.79 will be brutal. Save the money and get a 6-speed instead.
      Did you mean to say M50?

      If you did would your comments also apply to S50B30?

      Comment

      • OTT
        Member
        • May 2010
        • 83

        #4
        3.25 is perfect in my opinion. I'm running a 4.45 right now and looking for a 3.25-3.46 ratio. I'm around 4k at 60mph and top out at like 105mph. How many rpms are you spinning at 60mph?

        Comment

        • MSFIT
          Member
          • Mar 2009
          • 81

          #5
          Originally posted by nrubenstein
          3.25 with an S50 is sluggish. 2.79 will be brutal. Save the money and get a 6-speed instead.
          95 M3's came with 3.15's....96+ 3.23, auto's 3.38. In the e36 world, 3.38 is the diff to be had.

          I ran a 3.91 in my last E36 (Topped out at 121mph), currently running a 3.73 in the e30 with a g250 trans (haven't been the track yet). I would imagine running a 2.79 would be like me starting out in second gear, with the M50 it just doesn't have enough power. I've tried it a few times since my first gear is over with really quick, second I need to feather the clutch till it gets up to speed some.

          Comment

          • Uber E30
            E30 Fanatic
            • Aug 2008
            • 1409

            #6
            Originally posted by MSFIT
            95 M3's came with 3.15's....96+ 3.23, auto's 3.38. In the e36 world, 3.38 is the diff to be had.

            I ran a 3.91 in my last E36 (Topped out at 121mph), currently running a 3.73 in the e30 with a g250 trans (haven't been the track yet). I would imagine running a 2.79 would be like me starting out in second gear, with the M50 it just doesn't have enough power. I've tried it a few times since my first gear is over with really quick, second I need to feather the clutch till it gets up to speed some.
            The g250 has TOTALLY different gearing then a ZF, why would you even comment about yours.

            For the OP, a comparison in a stock e30... 3.25 is very close to a 4.10 and a 2.93 is close to a 3.73. Going anything below that only makes sense for turbo applications.
            -Alex

            Comment

            • dude8383
              Forum Sponsor
              • Jan 2005
              • 10387

              #7
              Originally posted by MSFIT
              95 M3's came with 3.15's....96+ 3.23, auto's 3.38. In the e36 world, 3.38 is the diff to be had.

              I ran a 3.91 in my last E36 (Topped out at 121mph), currently running a 3.73 in the e30 with a g250 trans (haven't been the track yet). I would imagine running a 2.79 would be like me starting out in second gear, with the M50 it just doesn't have enough power. I've tried it a few times since my first gear is over with really quick, second I need to feather the clutch till it gets up to speed some.
              I think that a compromise between a 3.25 and a 3.73 would be a 3.46 but those don't come up too often. I currently have a 3.25 lsd with my g250 and really like it. But then again, my m50 ain't so stock...
              IG: deniso_nsi Leave me feedback here

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              • OTT
                Member
                • May 2010
                • 83

                #8
                Originally posted by dude8383
                I think that a compromise between a 3.25 and a 3.73 would be a 3.46 but those don't come up too often. I currently have a 3.25 lsd with my g250 and really like it. But then again, my m50 ain't so stock...
                He's got a ZF not a Getrag 250.

                Comment

                • M-technik-3
                  I waste 90% of my day here and all I got was this stupid title
                  • Oct 2003
                  • 18946

                  #9
                  Great for saving fuel, if you feel 3.25 is too buzzy split the two and use a 2.93 or a 3.07.
                  https://www.facebook.com/BentOverRacing

                  Comment

                  • dude8383
                    Forum Sponsor
                    • Jan 2005
                    • 10387

                    #10
                    Originally posted by OTT
                    He's got a ZF not a Getrag 250.
                    Gearing is not THAT much different between the two. Just giving him a comparison.
                    IG: deniso_nsi Leave me feedback here

                    Comment

                    • BenM
                      R3VLimited
                      • Nov 2006
                      • 2184

                      #11
                      Originally posted by Uber E30
                      The g250 has TOTALLY different gearing then a ZF, why would you even comment about yours.

                      For the OP, a comparison in a stock e30... 3.25 is very close to a 4.10 and a 2.93 is close to a 3.73. Going anything below that only makes sense for turbo applications.
                      Bzzzt, wrong. The gearbox you're thinking that is totally different is the g260. g250 is an E34/e36 gearbox with 1:1 5th and nearly identical gearing to the ZF.

                      Also I don't know why anyone would go over a 3.46 if using a g250 or zf gearbox, when the 3.25 can be found pretty easily in most e28s.
                      Originally posted by BillBrasky
                      E36's are the Stephen Baldwin of the 3 series family. They barely hold everything together and they only sold a lot because of the popularity of their older sibling.
                      1991 318i Alpine II - S50/5-lug swapped - track car
                      1989 325i Cirrusblau - Daily
                      1970 2500 - Malaga over Grey Cloth
                      2012 F350 6.7PSD

                      Comment

                      • dude8383
                        Forum Sponsor
                        • Jan 2005
                        • 10387

                        #12
                        Originally posted by BenM
                        Bzzzt, wrong. The gearbox you're thinking that is totally different is the g260. g250 is an E34/e36 gearbox with 1:1 5th and nearly identical gearing to the ZF.

                        Also I don't know why anyone would go over a 3.46 if using a g250 or zf gearbox, when the 3.25 can be found pretty easily in most e28s.
                        Some guys like the 3.46 cause you'll get a bit more pick up from it. I'm not saying that I personally would rather have the 3.46 because I love my 3.25.



                        IG: deniso_nsi Leave me feedback here

                        Comment

                        • BenM
                          R3VLimited
                          • Nov 2006
                          • 2184

                          #13
                          Originally posted by dude8383
                          Some guys like the 3.46 cause you'll get a bit more pick up from it. I'm not saying that I personally would rather have the 3.46 because I love my 3.25.



                          http://r3vlimited.com/board/showthre...hlight=3.46lsd
                          For sure man. I run a 3.46 in my M50TU swapped car and love it since it delivers the most usable gearing for track/street driving, but its the shortest diff I would want to run with a 1:1 5th gear.
                          Originally posted by BillBrasky
                          E36's are the Stephen Baldwin of the 3 series family. They barely hold everything together and they only sold a lot because of the popularity of their older sibling.
                          1991 318i Alpine II - S50/5-lug swapped - track car
                          1989 325i Cirrusblau - Daily
                          1970 2500 - Malaga over Grey Cloth
                          2012 F350 6.7PSD

                          Comment

                          • Uber E30
                            E30 Fanatic
                            • Aug 2008
                            • 1409

                            #14
                            Originally posted by BenM
                            Bzzzt, wrong. The gearbox you're thinking that is totally different is the g260.
                            Ah you are right they are identical from 3rd-5th. I have no idea how someone would run a 3.91 then.



                            4.25k on the freeway, yuck
                            -Alex

                            Comment

                            • Elysian
                              Mod Crazy
                              • Apr 2010
                              • 674

                              #15
                              Originally posted by dude8383
                              Gearing is not THAT much different between the two. Just giving him a comparison.
                              I don't have anything to add to the subject besides the fact I'd never go with a gearing that tall, but you've got an amazing looking car.

                              Comment

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