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  • 6-speed box...

    Anybody else considered installing a six-speed gearbox from an E46 M3 ?

    The Z3 MC is an excellent car (esp. with a sorted chassis), however i believe that the engine gearing could be improved.

    Personally I find the Z3MC a little under-geared for motorway, and the steps between ratios too large for what is supposed to be a sports/GT car.

    ---------------------------------------------------------------
    A bit of Googling reveal the following info:
    M3 (S54) Z3MC (S50)
    1st 4.23 4.21
    2nd 2.53 2.49
    3rd 1.67 1.66
    4th 1.23 1.24
    5th 1:1 1:1
    6th 0.83:1 n/a
    FDR 3.62 3.15
    ---------------------------------------------------------------

    An E46 M3 gearbox, perhaps together with a shorter ratio diff from an E36 328i or a Z3 3.0, would be a good improvement.

    Understand that the E46 gearbox will bolt directly onto the S50 engine, and the Z3M transmission tunnel can accomodate the E46 gearbox casing.

    The only uncertain part of the job is the shorter propshaft. Any modifiction to the prop would affect its dynamic balancing -- a job for a professional enginnering company.

    Does anybody have any magazine articles or links to other BMW forums describing a similar project ?? (understand this is a popular mod in the goddam USofA)

    Thanks in advance, Will

  • #2
    Whilst I don't know about the packaging for the 6-speeder in the ZMC, I can recommend Dunning & Fairbank for propshafts. They made me a prop for the westfield when I moved the engine back and the Westfield prop was too long. They've been in the business for years and are reasonably priced.

    I think I paid around 100 GBP, although the westie prop is a single piece, whereas I expectr the ZMC's is a 2 parter with a joint in the middle? I guess it would cost something like 200 GBP for a new one or you could get the original modified and balanced by them.

    I'd check out the kit car press to find a prop company local to you.

    DC

    Comment


    • #3
      thanks David -- that's an excellent lead re. prop balancing :-)

      Comment


      • #4
        Originally posted by wfarrell View Post
        Anybody else considered installing a six-speed gearbox from an E46 M3 ?

        The Z3 MC is an excellent car (esp. with a sorted chassis), however i believe that the engine gearing could be improved.

        Personally I find the Z3MC a little under-geared for motorway, and the steps between ratios too large for what is supposed to be a sports/GT car.

        ---------------------------------------------------------------
        A bit of Googling reveal the following info:
        M3 (S54) Z3MC (S50)
        1st 4.23 4.21
        2nd 2.53 2.49
        3rd 1.67 1.66
        4th 1.23 1.24
        5th 1:1 1:1
        6th 0.83:1 n/a
        FDR 3.62 3.15
        ---------------------------------------------------------------

        An E46 M3 gearbox, perhaps together with a shorter ratio diff from an E36 328i or a Z3 3.0, would be a good improvement.

        Understand that the E46 gearbox will bolt directly onto the S50 engine, and the Z3M transmission tunnel can accomodate the E46 gearbox casing.

        The only uncertain part of the job is the shorter propshaft. Any modifiction to the prop would affect its dynamic balancing -- a job for a professional enginnering company.

        Does anybody have any magazine articles or links to other BMW forums describing a similar project ?? (understand this is a popular mod in the goddam USofA)

        Thanks in advance, Will
        Apparently it fits without any modifications, the only custom item is the propshaft. I get the impression it's usually the E36 M3 EVO 6-Speed that people look at fitting as our cars are E36-based but I think the E36 and E46 M3 6-speeders are very similar if not the same. The ratios shown are practically identical, but 6th is an "overdrive" gear and like you say the diff with the 6-speed gearbox makes the gearing shorter and closer together but still with a taller 6th cruising gear.

        E36 diffs won't fit out cars, the only diffs that fit are from E30s or Z3s (or E36 Compacts). Stuff from the older big BMWs fits too like E28 5-Series and some of the old 6-series but hardly any had LSDs.

        A 3.0i Z3 is a Torsen LSD (3.46 ratio); I've got a 3.38 from a 2.2i (8% lower) Torsen LSD diff fitted to mine and it seems fine, and does make the gearing feel closer together but of course it is at the expense of an even lower motorway gear; it's not too bad though but I don't think I could live with a 3.64 diff (15% lower) that other people on here have fitted. A 325i LSD would be a nice match with a 6 speed gearbox IMO and would keep the clutch-type LSD.
        Last edited by c_w; 09-12-2007, 03:08 PM.

        Comment


        • #5
          3.64 is the way to go!

          Comment


          • #6
            Six speed gearbox won't fit the Z3M.

            5 speed box is said to be stronger anyway.
            S54 Titan Silver metallic. Black leather, most factory options including sunroof, Becker Cascade and Becker Silverstone changer.

            Comment


            • #7
              Take a look at the pictures of the Z3 MC's gear box here:
              http://www.realoem.com/bmw/showparts...21&hg=23&fg=05
              and the E46 M3's here:
              http://www.realoem.com/bmw/showparts...22&hg=23&fg=05

              they appear to have different faces.
              /// Exdos ///
              "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

              Comment


              • #8
                Originally posted by ian View Post
                Six speed gearbox won't fit the Z3M.

                5 speed box is said to be stronger anyway.
                it will fit, you just have to shorten the prop shaft as said above.

                its about 6 hours to change a gearbox

                Comment


                • #9
                  Thanks for the info guys

                  ...maybe a box (or just bell housing?) from the Z4MC would fit ?

                  http://www.realoem.com/bmw/showparts...18&hg=23&fg=05

                  Comment


                  • #10
                    Originally posted by exdos View Post
                    Take a look at the pictures of the Z3 MC's gear box here:
                    http://www.realoem.com/bmw/showparts...21&hg=23&fg=05
                    and the E46 M3's here:
                    http://www.realoem.com/bmw/showparts...22&hg=23&fg=05

                    they appear to have different faces.
                    the z3m and the smg look almost the same fit?!
                    its the manual that not (looks wise) they both bolted onto the S50, so there must be an adapter cause the engine ends wont be different!

                    z3m


                    e36 6 speed


                    e36 smg

                    Comment


                    • #11
                      six speeder

                      Originally posted by BEN View Post
                      3.64 is the way to go!
                      but was thinking of the 6 speeder then it would be perfect for motorway driving .ive got a six speeder that ive had sitting in the garage for a while and just bought a 2nd hand prop the only thing that worries me as the 6 speeder is alledgedly not as strong i had a link to an american forum where its been done but cant find it now
                      i might have a go over the winter but i need to frinish my bike and off roader first
                      does any one know if the clutch and flywheel are the same ?
                      [GROWING OLD IS COMPULSARY ---- GROWING UP IS OPTIONAL

                      Comment


                      • #12
                        Originally posted by ragerover View Post
                        but was thinking of the 6 speeder then it would be perfect for motorway driving .ive got a six speeder that ive had sitting in the garage for a while and just bought a 2nd hand prop the only thing that worries me as the 6 speeder is alledgedly not as strong i had a link to an american forum where its been done but cant find it now
                        i might have a go over the winter but i need to frinish my bike and off roader first
                        does any one know if the clutch and flywheel are the same ?
                        yeah, but you have an e34 clutch in yours anyway.
                        it would'nt cost more than about £1200

                        Comment


                        • #13
                          Originally posted by ragerover View Post
                          but was thinking of the 6 speeder then it would be perfect for motorway driving .ive got a six speeder that ive had sitting in the garage for a while and just bought a 2nd hand prop the only thing that worries me as the 6 speeder is alledgedly not as strong i had a link to an american forum where its been done but cant find it now
                          i might have a go over the winter but i need to frinish my bike and off roader first
                          does any one know if the clutch and flywheel are the same ?
                          I've read the same too about it not being as strong, but the every M3 EVO had this box fitted so I suppose it's not as though it's completely unreliable. The only aspect putting me off is that it's apparently more notchier than ours?

                          3.64 and 6-speed would be a very nice setup and should have come like this from the factory; quicker acceleration in gear and better high speed cruising. The M3 EVO runs a 3.23 diff so is very long geared in 6th, the E46 had lower gearing and so does the new E92 M3 (in fact I've read that it has the same 6th gear mph/1000rpm as our 5th!!).

                          3.64 and the standard gearbox is too low IMO unless you don't drive long distances a lot. Mine shows just under 3300rpm at 70mph and that's more than enough for me!

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