Announcement

Collapse
No announcement yet.

No more r3vtard assist

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #46
    Question on ES 2.9x vs. IS 3.7x LSD units.


    I have a good 2.9x LSD full assembly and a 3.7x LSD full assembly that has worn discs and a broken spider-gear shaft. Originally I was going to swap the LSD units between the 2 (put the 3.7 gear onto the 2.9 unit) to rebuild the 3.7 assembly, but it seems that cant be done.

    So, what parts CAN be used from the 2.9 to rebuild the 3.7? Internals of the unit OK to swap over? Is there some combination of parts that would allow for an increased # of discs/plates to help improve lock-up for racing application?
    Ben
    Thelma-Louise, the '88is Chump Car - back to M20 power!

    2014 ChumpCar Season Schedule!
    April 5-6 Autobahn, IL - Sat: 1st! Sun: 3rd
    May23-25 Watkins Glen, NY: 4th, 5th, 4th
    October 4 PittRace Sprints: 2nd in C-class
    October 18-19 NCM, Bowling Green KY: 2nd, 1st!
    Nov 1-2 Watkins Glen - Chumpionship - 1st car to exit the race with significant body damage :(

    Find us on FB! Schaut Speed Motorsports

    Comment


      #47
      deleted
      Last edited by Wanganstyle; 09-09-2020, 04:46 PM.
      OBD1 M54/M52TU swap as a M50b25

      Z4 non powered steering rack fits e30



      Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

      Comment


        #48
        Thanks - it sounds like I should have no problem swapping the internals of the LSD unit from the 2.9 to the 3.7, which will give me a good usable spare. I plan to build the other current good unit (with worn clutches) into the 2/1 setup. Is there any big performance advantage to going to the Bimmerworld motorsports clutch discs over the OEM organic ones? And to confirm, are the BMW OEM discs same as Porsche ones (I have only been able to find part # for Porsche - 95133255100)




        That broken diff was in our ChumpCar, broke during a 25 hr race. Started with worn discs and low % lock-up, which slowly wore as the race went on and lock-up reduced even more. It was acting pretty much like an open diff by the 12 hour mark, and we kept going on it (at that time the spare was the 2.9 diff). Eventually, it changed itself to a locked diff (when the spider shaft broke and the gears lodged themselves in a way to lock the diff). My hypothesis on what finally broke that shaft was repeated banging back and forth due to accel/decel and the turns - the system taking up that bit of slack, which was increased due to lack of friction material.
        Ben
        Thelma-Louise, the '88is Chump Car - back to M20 power!

        2014 ChumpCar Season Schedule!
        April 5-6 Autobahn, IL - Sat: 1st! Sun: 3rd
        May23-25 Watkins Glen, NY: 4th, 5th, 4th
        October 4 PittRace Sprints: 2nd in C-class
        October 18-19 NCM, Bowling Green KY: 2nd, 1st!
        Nov 1-2 Watkins Glen - Chumpionship - 1st car to exit the race with significant body damage :(

        Find us on FB! Schaut Speed Motorsports

        Comment


          #49
          deleted
          Last edited by Wanganstyle; 09-09-2020, 04:47 PM.
          OBD1 M54/M52TU swap as a M50b25

          Z4 non powered steering rack fits e30



          Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

          Comment


            #50
            would it be possible to see a picture(s) of what needs to be machined in a lathed for the 4 disc mod? i found a 188mm diff sitting at work. its condition is unknown. and i might not even be able to use it. as i have a feeling its one of the spares for the company race car.

            i have a feeling it will all become painfully obvious what will need to be done once i get into it. but id just like to be confident first. and im assuming all that comes off is the exact difference of the added steel and friction disc that is going in?

            thanks, leigh

            Comment


              #51
              you machine what's touching the table in this picture


              Status: HG repair. 488wtq though!

              Comment


                #52
                cool. thanks for that. that clears that up for me before i even get into it.

                im assuming. for argument sakes if the added steel and disc are 6mm in total thickness. i need to machine 3mm off each side bearing to keep it all centre?

                Comment


                  #53
                  wha? nah. each clutch stack is about 2mm thick (if you don't get thicker plates). So you just need to machine off the cap 4mm. Course, you could machine off less for more preload.

                  Status: HG repair. 488wtq though!

                  Comment


                    #54
                    deleted
                    Last edited by Wanganstyle; 09-09-2020, 04:47 PM.
                    OBD1 M54/M52TU swap as a M50b25

                    Z4 non powered steering rack fits e30



                    Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

                    Comment


                      #55
                      Thanks for the write-up! Finished rebuilding the spare diff into a 3-disc setup, and replacing the broken bits, by scavenging parts out of my 'ES' diff. It was easy. Took me 2.5 hours to completely disassemble the 2 units, clean parts up, measure and reassemble the 1 unit. And now I have a good spare :)

                      A few pics from the process - first up, what came out of the 3.73. Notice the spider gears/shafts.... oops.




                      Parts measured up right, spacer that gets pulled and the disc/plate can that goes back in.


                      Thickness shot -



                      The mess of parts from both LSD units, laid out in 2 sets of rows - bottom rows are bottom of LSD unit from spacer/washer to spider gear carrier, top 2 rows is top of spider gear carrier to the top spacer washer - all match up. I measured up all the clutch disc/plates and used the 3 best - signified by the "O"s. The large spacer that gets replaced by the extra disc is the first large disc on the bottom row.




                      And the finished product.

                      Last edited by NigelStu; 07-31-2012, 08:40 AM.
                      Ben
                      Thelma-Louise, the '88is Chump Car - back to M20 power!

                      2014 ChumpCar Season Schedule!
                      April 5-6 Autobahn, IL - Sat: 1st! Sun: 3rd
                      May23-25 Watkins Glen, NY: 4th, 5th, 4th
                      October 4 PittRace Sprints: 2nd in C-class
                      October 18-19 NCM, Bowling Green KY: 2nd, 1st!
                      Nov 1-2 Watkins Glen - Chumpionship - 1st car to exit the race with significant body damage :(

                      Find us on FB! Schaut Speed Motorsports

                      Comment


                        #56
                        ^
                        awesome pics... I really needed those to visualize what I will be doing.
                        1997 BMW 328ic 5spd sport Moreagrun Metallic
                        1989 BMW 325is 5spd with a M50 swap
                        2006 Audi A3 6spd DSG sport with APR stg 2

                        Comment


                          #57
                          I was hoping that the pics could help someone. :D
                          Ben
                          Thelma-Louise, the '88is Chump Car - back to M20 power!

                          2014 ChumpCar Season Schedule!
                          April 5-6 Autobahn, IL - Sat: 1st! Sun: 3rd
                          May23-25 Watkins Glen, NY: 4th, 5th, 4th
                          October 4 PittRace Sprints: 2nd in C-class
                          October 18-19 NCM, Bowling Green KY: 2nd, 1st!
                          Nov 1-2 Watkins Glen - Chumpionship - 1st car to exit the race with significant body damage :(

                          Find us on FB! Schaut Speed Motorsports

                          Comment


                            #58
                            oh man. thats awesome. those pics made everything real clear!!! thanks heaps. should be tonnes easier now.

                            Comment


                              #59
                              deleted
                              Last edited by Wanganstyle; 09-09-2020, 04:47 PM.
                              OBD1 M54/M52TU swap as a M50b25

                              Z4 non powered steering rack fits e30



                              Euro e46 2005/6 320d 6mt gearbox into E30 with M20 hardy and beck 1985 327s engine

                              Comment


                                #60
                                Some very interesting information in this topic.

                                I would like to add that it is possible to machine the stock E30 ramp plates to 30º

                                I have done so



                                They were then re-hardened and polished.



                                Here is a 1.5way E36 ramp set, and I understand why the E36 planetary gear pins would be weaker, but they are a far superior design over the E30 ones, and unless you are running 1000hp (which 99.5% of all E30's and or E36's) are not, I would be fitting the E36 pins.



                                You can also buy the correct 30º from BMW or from C3, but they are pricey at £300.

                                http://www.c3bmw.co.uk/StockItem.asp...&Item=unassign

                                Andrew


                                Andrew AT E30zone.co.uk | H23-is | S14

                                Comment

                                Working...
                                X