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E30 318i sedan lsd possible?!

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    E30 318i sedan lsd possible?!

    Hi i have an e30 1991 318i sedan last 7 digits of the vin (EJ00821) with open diff i think its a small case 3.45 ratio if i want to get an LSD for it what options i have like converting the same case with an lsd components or i have to buy a complete LSD unit and if any of the options what i have to get to fit right on no hard modifications ;)
    Plus here is a pic of my current diff might help!




    Cheers

    #2
    Converting the case you have to an LSD unit would probably be more complicated than what most DIY'ers can do, and if you were to change the ratio then the chances of success are even lower as pre-loading the pinion gear and output flange bearings requires tools that almost nobody has at home.

    Most people buy a complete, working, used LSD unit and swap it in. IMO many or most of them are going to be totally worn out, at least in the price range most people are willing to pay. I think that Torsen gear diffs from Z3's are more or less direct bolt-ins and can be found for ~$500. These are gear diffs which have some advantages over clutch-type diffs, but the disadvantage that if you lift a wheel or drive on ice it will behave like an open diff. The rest of the time they are awesome though since they do not have a fixed torque bias ratio and will automatically adjust the amount of torque delivered to each wheel to ensure that neither one slips.

    You can go with a newly built/rebuilt LSD unit, but that sort of thing starts well above $1000 and the sky is the limit, so to speak.

    Transaction Feedback: LINK

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      #3
      So you have a 168mm diff. Us 2002 guys have driven up LSD prices by quite a bit. However, you can certainly keep an eye out for an E30 or E36 318i LSD pumpkin to swap in.

      1) Do you plan on keeping the same ratio? If yes, your work and chances of success will be exponentially higher.

      2) What is your mechanical aptitude?
      ADAMS Autosport

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        #4
        I would do either a 3.25 medium case or a 3.46 medium case LSD at that point. It would be a lot easier to source.
        IG: deniso_nsi Leave me feedback here

        Comment


          #5
          So are 4.10 small case units now super difficult to source? The last time I bought a used one was a decade ago and I think I paid $300 lol.

          Transaction Feedback: LINK

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            #6
            Originally posted by bmwman91 View Post
            So are 4.10 small case units now super difficult to source? The last time I bought a used one was a decade ago and I think I paid $300 lol.


            I havent seen a 4.10 small case lsd in a while and have been looking for my car.


            1989 325is l 1984 euro 320i l 1970 2002 Racecar
            1991 318i 4dr slick top


            Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
            Vintage race car revival (2002 content)
            Mtech 2 turbo restoration
            Brilliantrot slick top "build"

            Comment


              #7
              Originally posted by bmwman91 View Post
              Converting the case you have to an LSD unit would probably be more complicated than what most DIY'ers can do, and if you were to change the ratio then the chances of success are even lower as pre-loading the pinion gear and output flange bearings requires tools that almost nobody has at home.

              Most people buy a complete, working, used LSD unit and swap it in. IMO many or most of them are going to be totally worn out, at least in the price range most people are willing to pay. I think that Torsen gear diffs from Z3's are more or less direct bolt-ins and can be found for ~$500. These are gear diffs which have some advantages over clutch-type diffs, but the disadvantage that if you lift a wheel or drive on ice it will behave like an open diff. The rest of the time they are awesome though since they do not have a fixed torque bias ratio and will automatically adjust the amount of torque delivered to each wheel to ensure that neither one slips.

              You can go with a newly built/rebuilt LSD unit, but that sort of thing starts well above $1000 and the sky is the limit, so to speak.
              Ok so if i cant or its hard to convert the small case what other options ihave like i dont really care about the ratio unless it will effect because i have an M42 engine still in !! Lets say i sort a medium case lsd with what ever ratio is it bolt on swap or still iam going to change the drive shaft ? And what ratio will be the best for the m42 engine ? And what medium case i can use for example out of what BMW that i can swap easier if any part number?

              Comment


                #8
                Originally posted by SkiFree View Post
                So you have a 168mm diff. Us 2002 guys have driven up LSD prices by quite a bit. However, you can certainly keep an eye out for an E30 or E36 318i LSD pumpkin to swap in.

                1) Do you plan on keeping the same ratio? If yes, your work and chances of success will be exponentially higher.

                2) What is your mechanical aptitude?
                Ratio its not a problem as long as it will be ok with the m42 engine power iam thinking of maybe swapping the engine to an m54 out of the X5 SO IAM THINKING of getting an LSD and maybe keeping it even when i will swap the engine any possibility? To handle the difference in power between m42 and m54 ?!

                Comment


                  #9
                  Originally posted by dude8383 View Post
                  I would do either a 3.25 medium case or a 3.46 medium case LSD at that point. It would be a lot easier to source.
                  Those two options are they bolt on or i have to do some mods to get them to fit if yes any good source to do the modifications or what the steps ?

                  Comment


                    #10
                    If you have a stock M42, I really recommend a 4.10 ratio. That is what it had stock, and unless fuel economy is your main priority, the 4.10 will make it feel a lot more fun.

                    Medium case diffs are also a direct bolt-in, just make sure to loosen the collar nut that holds the two driveshaft halves together when yo install it to adjust for any length/positional differences and then re-tighten it when done.

                    Transaction Feedback: LINK

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                      #11
                      Yeh based on your 3.45 I thought you were going for fuel economy. A 4.10 will keep the car in its powerband.
                      IG: deniso_nsi Leave me feedback here

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                        #12
                        I have this that might be of interest to you:

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                          #13
                          Anyone know what a 4.27 would be like? I got a medium case 4.27 to rebuild. Wondering what it would be like behind an m42


                          1989 325is l 1984 euro 320i l 1970 2002 Racecar
                          1991 318i 4dr slick top


                          Euro spec 320i/Alpina B6 3.5 project(the never ending saga)
                          Vintage race car revival (2002 content)
                          Mtech 2 turbo restoration
                          Brilliantrot slick top "build"

                          Comment


                            #14
                            3.45 is an E36 ratio- op, which transmission do you have?
                            I'm wondering if maybe you've had a trans swap. E36 has no overdrive...

                            fwiw, an E36 318ti diff will work, and for some reason, those seemed to come
                            with an LSD more often than makes sense for what BMW was selling as an 'economy' car.

                            t
                            now, sometimes I just mess with people. It's more entertaining that way. george graves

                            Comment


                              #15
                              Narsiyousif, you are planning an M/S5x engine swap, right? If so, then that changes things a lot. You will probably want a medium case diff since it is stronger, and also a 3.73 or 3.45 ratio will be fine.

                              Transaction Feedback: LINK

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