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  • Torsen V8 rear diff swap! How-to.

    Here's a small how-to on swapping the open S2 diff for a V8 torsen one.

    I'll start this at the point where you have both diffs in front of you on the bench.

    - Drain all the oil from both diff's
    - Remove both the driveshaft flanges from both diff's
    - Remove the casing-cover that sits behind the driveshaft flange, on both diff's. That casing is bolted to the diff housing itself with 9 bolts.
    - Remove both diffs out of it's housing
    - Then remove the O-ring seal at the far end of the diff housing from both the V8 diff and S2 diff.
    The reason for that; is that one of the two driveshaft flanges from the S2 is different then from the V8. The V8 driveshaft flange has a thicker diameter at the point where it seals with the O-ring. We need the V8 driveshaft flange eventually on the S2 diff housing.
    These O-rings are metal, and are pressed in the diff housing. They can be removed by driving them out with a pendriver and a hamer from the inside out.
    Ofcourse it will be better to replace the V8 O-ring with a new O-ring. Just make sure its not damaged if you use it or dried out.
    - Press the V8 O-ring in the S2 diff housing. You will notice that the inside diameter from the V8 O-ring is bigger then the S2 O-ring.

    - Passing on to the diffs itself.
    - Remove the crown wheels from both diff's (bolted with 10 bolts). And swap them around. So S2 crown wheel onto the V8 Torsen Diff. Retighten the bolts at xx NM (will need to check what NM's I tightened the bolts)
    - Drop the V8 Torsen diff in its new S2 housing
    - Make sure all bearings are clean. Apply some liquid gasket on the surface where the casing-cover meets the diff casing. Then put the casing-cover to close the diff again.
    - Retighten the 9 bolts
    - Mount the V8 driveshaft flange on the side were you swapped the O-ring
    And on the other side IIRC the S2 driveshaft can be fitted.
    - retighten the bolts from both shaft flanges
    - Check if there's any play on the diff bearings and that it turns easily
    - Fill the diff with some fresh oil. And check for leaks.
    - Get it back under the car asap!! And while you're at it, throw in a powerflex diff rubber aswell.

    Enjoy some sideways actions!!

    I'm not responsible if there's a failure because someone used this method to swap his diff. If you do this swap, use your common sence and check every step for yourself.

    Cheers guys!
    Last edited by Jeffer; 15 June 2005, 17:00.
    RS2 Black - stock 315 HP
    RS2 RS blau - stock 315 HP
    Sport Quattro - 1005 HP
    High Octane website

  • #2
    Gr8 info Jeffer I'll keep this is favorites for future
    Cheers
    sigpic_________
    Rob

    Comment


    • #3
      Why do you need to change the drive flange on the left side? Can't you just use the S2 version? Are you saying that the V8 flange is actually thicker were the seal is seated than the S2 eventough the S2 has a "gear" stuck on the flange? What about dialing the gears in? Aren't you supposed to do that? I mean, at least backlash.


      Well cool, finally a write up on a idea I had about a year ago. Too bad I'm all forum and no garage... I'm in the process right now, I'll be the first on my street at least! Great goin' Jeffer!

      Comment


      • #4
        Originally posted by Henka
        Why do you need to change the drive flange on the left side? Can't you just use the S2 version? Are you saying that the V8 flange is actually thicker were the seal is seated than the S2 eventough the S2 has a "gear" stuck on the flange? What about dialing the gears in? Aren't you supposed to do that? I mean, at least backlash.


        Well cool, finally a write up on a idea I had about a year ago. Too bad I'm all forum and no garage... I'm in the process right now, I'll be the first on my street at least! Great goin' Jeffer!
        Yes, the V8 flange has a thicker shaft then the S2 flange. Hence the swap of the O-ring aswell.

        Cheers
        Last edited by Jeffer; 15 June 2005, 21:15.
        RS2 Black - stock 315 HP
        RS2 RS blau - stock 315 HP
        Sport Quattro - 1005 HP
        High Octane website

        Comment


        • #5
          Wierd... Really wierd. But ok. Then I know I need a V8 flange and seal too. Good.

          Comment


          • #6
            Great stuff Jeffer... and qudos to Henka too for the original notion on this.

            Some Q's though:
            How long for the task ?
            Anything special to be aware of regarding the difflock mechism - does it need removed and blanked off or does the actuator simply not interfere with the motion of the Torsen.

            Jeffer - you can be the 1st S2 owner to stick a TT badge on your car - meaning 'Twin Torsen' of course. Especially ironic as the TT doesn't use Torsen !

            Paul
            Paul Nugent
            Webmaster http://S2central.net
            Administrator http://S2forum.com

            1994 S2 Coupe ABY - aka Project Lazarus
            2001 A6 allroad 2.5TDi - family tank
            2003 S4 Avant 4.2 V8 - daily burble

            Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

            There are only 10 kinds of people that understand binary - those that do, and those that don't

            Comment


            • #7
              Originally posted by S2central.net
              Anything special to be aware of regarding the difflock mechism - does it need removed and blanked off or does the actuator simply not interfere with the motion of the Torsen.
              Same question. Would it be posible to keep the difflock ? It helps a lot when dragracing.
              AKmotorsport.net - Manufacturing Motorsport parts that do the job. | Audi S2 on Facebook | Best way of reaching me is sending email to albert@akmotorsport.net

              Comment


              • #8
                Morning,

                Well it took us about 30 to 45 minutes to do the whole swap. What took the most time was the drainplug. That thing was corroded. We welded a bolt a bar to untighten it.
                The difflock actuator is still on my diff. The lever that sits inside the diff aswell. everything else i removed.
                It didn't look really an easy job to make the diff-lock function work on the Torsen. The bits needed for the difflock are not present on the torsen diff. And these bits are not easely made on the torsen. That requires some serious machining.

                I will have another close look with Cees on this. Maybe we can fabricate something.
                I did some launches now in 1st. On wet and dry. But no spinning what so ever, and that with 650 NM on there

                Cheers



                Originally posted by S2central.net
                Great stuff Jeffer... and qudos to Henka too for the original notion on this.

                Some Q's though:
                How long for the task ?
                Anything special to be aware of regarding the difflock mechism - does it need removed and blanked off or does the actuator simply not interfere with the motion of the Torsen.

                Jeffer - you can be the 1st S2 owner to stick a TT badge on your car - meaning 'Twin Torsen' of course. Especially ironic as the TT doesn't use Torsen !

                Paul
                RS2 Black - stock 315 HP
                RS2 RS blau - stock 315 HP
                Sport Quattro - 1005 HP
                High Octane website

                Comment


                • #9
                  Jeffer - I'm not looking to try and make the difflock function work with the Torsen - I don't think its wise - I just wanted to make sure that its easy removed or ignored. Thanks for clarifying and yes those drain plugs can be evil !

                  Albert - I dunno how a locked rear diff would help with drag-style launches. Drag strips are straight ! I fully realise how a locked centre diff would be useful in that situation though - thats what I would do if running an 016 gearbox for launches. The nose lift at launch on a high powered quattro with any sort of slipping centre differential has the potential for some wheel spin at the front wheels, but a locked centre diff would distribute torque evenly to both axles...

                  Paul
                  Paul Nugent
                  Webmaster http://S2central.net
                  Administrator http://S2forum.com

                  1994 S2 Coupe ABY - aka Project Lazarus
                  2001 A6 allroad 2.5TDi - family tank
                  2003 S4 Avant 4.2 V8 - daily burble

                  Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                  There are only 10 kinds of people that understand binary - those that do, and those that don't

                  Comment


                  • #10
                    Using manual lock with torsen will probably break things. Torsen applies more torque to the more grippy side and as the other flange is locked to the torsen base and the other flange is not... I'd say it will break.
                    -

                    Comment


                    • #11
                      Originally posted by porkkis
                      Using manual lock with torsen will probably break things. Torsen applies more torque to the more grippy side and as the other flange is locked to the torsen base and the other flange is not... I'd say it will break.
                      I'm not with you on that. If you can lock the rear diff, then theres no tension on the internals of the diff. So the function of locking both sides will be the same. You still can't go round a corner, torsen or not.

                      To me it the difflock is useless when installing the Torsen.
                      RS2 Black - stock 315 HP
                      RS2 RS blau - stock 315 HP
                      Sport Quattro - 1005 HP
                      High Octane website

                      Comment


                      • #12
                        Originally posted by S2central.net
                        Albert - I dunno how a locked rear diff would help with drag-style launches. Drag strips are straight ! I fully realise how a locked centre diff would be useful in that situation though - thats what I would do if running an 016 gearbox for launches. The nose lift at launch on a high powered quattro with any sort of slipping centre differential has the potential for some wheel spin at the front wheels, but a locked centre diff would distribute torque evenly to both axles...

                        Paul
                        Heve to revaluate what I have wrote.
                        AKmotorsport.net - Manufacturing Motorsport parts that do the job. | Audi S2 on Facebook | Best way of reaching me is sending email to albert@akmotorsport.net

                        Comment


                        • #13
                          I'm with Porkkis on this one - I always thought you cannot lock a Torsen, but until I start pulling these things apart then its impossible for me to visualise the locking mechanism and how it might affect the Torsen.

                          Paul
                          Paul Nugent
                          Webmaster http://S2central.net
                          Administrator http://S2forum.com

                          1994 S2 Coupe ABY - aka Project Lazarus
                          2001 A6 allroad 2.5TDi - family tank
                          2003 S4 Avant 4.2 V8 - daily burble

                          Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                          There are only 10 kinds of people that understand binary - those that do, and those that don't

                          Comment


                          • #14
                            I think we all have the same thought on this. One tells different then the other.

                            It's possible to make a mechanism to lock the Torsen. but:

                            It would require some VERY serious machining and parts fabrication
                            It would be totally useless because it has the LSD characteristics

                            Basicly when you lock a diff. The outside diff housing thats connected to the right shaft, will be connected to the left shaft. Thus by-passing all the internal Torsen sprockets. And then it would perform the same as you lock an open diff.

                            For sprints, like paul says, it would be wiser to put a torsen upfront aswell. Cees and I are soon pulling an 01E gearbox to see if we can fit the torsen in there aswell.

                            Then I can still have the TT badge "Triple Torsen"
                            RS2 Black - stock 315 HP
                            RS2 RS blau - stock 315 HP
                            Sport Quattro - 1005 HP
                            High Octane website

                            Comment


                            • #15
                              Yes indeed... I also spotted the future proof nature of the 'TT' badge !

                              Quaife have an ATB unit for the 01E variant that is used in the S4/RS4 - that's got to be a good candidate for a fit. Lee was looking into this a long time back, but I guess since the MRC venture has kicked off that he has other priorities on his plate.

                              If I was making a serious competition car out of an S2, I'd go with Torsens front and rear and a lockablecentre diff. That formula worked just great for the Ur WRC cars - well they actually ran without any centre diff - effectively giving them a full time locked centre. I believe the reason for this was simplicity, durability and handling consistency on the limit.

                              For a roadgoing car I think the lockable centre diff from an 016 box is the best way forward cos you would get really hacked off with full time locked centre and silly tyre wear on day to day driving.

                              Paul
                              Paul Nugent
                              Webmaster http://S2central.net
                              Administrator http://S2forum.com

                              1994 S2 Coupe ABY - aka Project Lazarus
                              2001 A6 allroad 2.5TDi - family tank
                              2003 S4 Avant 4.2 V8 - daily burble

                              Purveyor of HomeFries and Exclusive agent for Samco hose kits (S2/RS2)

                              There are only 10 kinds of people that understand binary - those that do, and those that don't

                              Comment

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