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  • Group N damping/rebound specs

    I am wondering what are the specs of Bilstein's shocks. It could be 300/300 at the front (sometimes they are revalved to 300/320 for a slower rebound), but I have no clue for the rear. Could it be something like 240/240?

    BTW Grp N Bilies have the rates scripted on their body.

    TIA

    Lee


    [email protected]

    1969 2002 racecar
    1989 M3 racecar
    e39 Touring

  • #2
    From http://www.bilstein.de/en/products/s...catalogue.html

    BILSTEIN - B6 SPORT
    Gas Pressure;
    Fitting Position Rear Axle, Parameter 160/55;
    outside diameter strut 51 mm

    BILSTEIN - B6 SPORT
    Gas Pressure;
    Fitting Position Rear Axle, Parameter 140/60;
    outside diameter strut 51 mm

    BILSTEIN - MOTORSPORT
    Gas Pressure, Model Rennen Gruppe N;
    Fitting Position Front Axle, Parameter 300/300;
    Fitting Position Rear Axle, Parameter 200/200;

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    • #3
      Thank you very much sir!!! ;-)


      [email protected]

      1969 2002 racecar
      1989 M3 racecar
      e39 Touring

      Comment


      • #4
        For reference, there is an old listing for 'Club sport race' inserts/shocks for E30s with part numbers P36-0135 (front) and B36-0604 (rear). Their valving is:

        P36-0135 300/120
        B36-0604 260/120

        Anyone know anything about these?


        http://www.forza.se/listor/Bilstein%20Racing%20Stotdampare%20Kund.PDF

        Comment


        • #5
          Nicely done...this forum rules!
          "Straights are for fast cars,turns are for fast drivers"

          Comment


          • #6
            Currently trying to find the specs on 24-014700
            They are MB W124 parts, and much stiffer than the e30 part, and shorter

            http://web1.carparts-cat.com/default...5018004&12=140

            http://www.youtube.com/watch?v=UXgYm...ture=endscreen

            Lee
            Last edited by LeeVuong; 03-01-2012, 03:43 PM.


            [email protected]

            1969 2002 racecar
            1989 M3 racecar
            e39 Touring

            Comment


            • #7
              Originally posted by LeeVuong View Post
              Currently trying to find the specs on 24-014700
              They are MB W124 parts, and much stiffer than the e30 part, and shorter

              http://web1.carparts-cat.com/default...5018004&12=140

              http://www.youtube.com/watch?v=UXgYm...ture=endscreen

              Lee
              I note the 24-014700 are B36 shocks with a 36mm piston. Why not go for a larger B46 as a starting base?

              Comment


              • #8
                Originally posted by LeeVuong View Post
                Thank you very much sir!!! ;-)
                Lee,

                You're welcome.

                I'd be interested in what you find with the MB shocks.

                All,

                Does anyone know if the Bilsteins are linear, progressive, etc.? There's a pretty cool write-up on Honda-Tech about rebuilding Bilsteins, shock testing, etc. All DIY type-stuff.

                Gregg

                Comment


                • #9
                  BMW factory Grp N has (or had) two sets of rates. Fronts: 235/270 & 300/300 Rears: 165/170 & 200/200.

                  Mike K.
                  Last edited by Mike K.; 03-03-2012, 02:41 AM.

                  Comment


                  • #10
                    Originally posted by DSM2002 View Post
                    ...'Club sport race' inserts/shocks for E30s with part numbers P36-0135 (front) and B36-0604 (rear). Their valving is:
                    P36-0135 300/120
                    B36-0604 260/120
                    I ordered a set of these about two weeks ago from www.sellholm.se shortened to match the free length of the GrpN springs.

                    Both Bilstein workshops I have talked too do not recommend the GrpN shocks unless you are running a race car with multipoint welded cage and slicks. Those GrpN dampers are seriously stiff.
                    I have been told that those GrpN damper setting derived from an optimization within technical race regulation and tracks raced at that time.

                    I choose the Club Sport setting because I am only running semi-slicks and doing track days on track and the car is not caged (yet). Furthermore the tracks are generally about 2.5 km in length and relatively twisty so there is not that big amount of sweeping true high speed corners.

                    Comment


                    • #11
                      Originally posted by Gregg View Post
                      There's a pretty cool write-up on Honda-Tech about rebuilding Bilsteins, shock testing, etc.

                      Gregg
                      DIY Shock Dyno

                      http://honda-tech.com/showthread.php?t=2325055

                      DIY Bilstein Revalve

                      http://honda-tech.com/showthread.php...evalve+project

                      http://honda-tech.com/showthread.php...evalve+project

                      Hope this helps,

                      Gregg

                      Comment


                      • #12
                        Originally posted by Gstlund View Post

                        Both Bilstein workshops I have talked too do not recommend the GrpN shocks unless you are running a race car with multipoint welded cage and slicks. Those GrpN dampers are seriously stiff.
                        I used to run the softer of the Grp N setup, sometimes called the "rain-setup".
                        It's quite stiff and really not suited for a road car.
                        But on dry tracks it had it's limits and I would have wanted the stiffer shocks.


                        Goodbye M3, you served me well.

                        Comment


                        • #13
                          I have located a reference with some specs on some of the relevant Bilsteins which may help:

                          BMW 325i HD FRONT
                          Compressed: 530
                          Extended: 618
                          Rebound: 2320 N
                          Compression: 800 N
                          P36-0136

                          BMW 325i SPORT FRONT
                          Compressed: 515.0
                          Extended: 597
                          Rebound: 2330 N
                          Compression: 755 N
                          P36-0335

                          BMW 325iX 4WD FRONT
                          Compressed: 438
                          Extended: 511
                          Rebound: 1365 N
                          Compression: 465 N
                          P36-0251

                          BMW 3-SERIES E30 SPORT REAR
                          Compressed: 333
                          Extended: 529
                          Rebound: 1650 N
                          Compression: 565 N
                          B36-2027


                          BMW 3 SERIES E30 HD REAR
                          Compressed: 333
                          Extended: 551
                          Rebound: 1650 N
                          Compression: 565 N
                          B36-2028

                          MERCEDES BENZ R
                          Compressed: 336
                          Extended: 471
                          Rebound: 2870 N
                          Compression: 900 N
                          B36-1470


                          Most here will know that conventionally, Bilstein ratings are written as one tenth the damping force in Newtons. EXAMPLE: for a shock rated 287/90 and rebound force is 2870 Newtons at 0.52 and compression force is 900 Newtons at 0.52. Interestingly the iX inserts which are 86mm shorter are very light on with their valving compared to stock Billies.

                          Rebound on those Merc shock seem quite stiff based on figures and are not far from the rear Club Sport figures above.






                          Originally posted by Gstlund View Post
                          I ordered a set of these about two weeks ago from www.sellholm.se shortened to match the free length of the GrpN springs.

                          Both Bilstein workshops I have talked too do not recommend the GrpN shocks unless you are running a race car with multipoint welded cage and slicks. Those GrpN dampers are seriously stiff.
                          I have been told that those GrpN damper setting derived from an optimization within technical race regulation and tracks raced at that time.

                          I choose the Club Sport setting because I am only running semi-slicks and doing track days on track and the car is not caged (yet). Furthermore the tracks are generally about 2.5 km in length and relatively twisty so there is not that big amount of sweeping true high speed corners.

                          Have you been able to trial the 'Club Sport' shocks? How do you find them?
                          Last edited by DSM2002; 06-14-2012, 09:56 PM.

                          Comment


                          • #14
                            Originally posted by DSM2002 View Post
                            Have you been able to trial the 'Club Sport' shocks? How do you find them?
                            Yes, finally I had have the opportunity to test them both on road and track.
                            On the road I find them firm but not harsh. Ok, driving the stone paved road in centre of town or driving over sharp edged frostlifts isn't that comfortable. But that wasn't a part of the requirement.

                            So track then. So far only one track day done at Kinnekulle Ring (2012-06-17), a twisty technical circuit. Compliant and well controlled are the words I would use to describe the feeling of the dampers. The track has develop some nasty bumps in a corner but although they felt the car wasn't unsettled.
                            (You both see and hear them at 1.30 in one the racers video, http://www.youtube.com/watch?feature...S3AstzeQ#t=93s, from one of races that day.)

                            So have gotten what I wanted, a god street and track compromise? Yes, I'm satisfied.

                            I have the damper curves for my dampers. The values not the same as listed above. So for the record I list my my values but remember these values is only a small part of hole truth. Front 390/200, Rear 200/165.

                            Comment


                            • #15
                              As a follow-up to this thread, I will soon add more damper and spring specs soon. I am helping set-up Jean-Luc Bergeron's M3 for Targa Newfoundland. The car is currently set-up for racing (Goup N dampers and 600frt/900rr springs). The suspension is removed in favor of softer Bilstein Rallye dampers to be mated to 300fr/450rr main springs plus front and rear tender springs. Targa is all tarmac, but bumpy in some stages. Car height will be about the same as stock. We are currently debating on sway bars. Stock front and no rear. Or no swaybars at all. Targa is bumpy and can be very wet, therefore maximum traction is needed.

                              BTW The car was built by Ron Checca years ago.
                              http://www.targanewfoundland.com/drivers/cars/2012/222/

                              There's another M3 in the entry list
                              http://www.targanewfoundland.com/drivers/cars/2012/27/
                              Last edited by LeeVuong; 08-25-2012, 03:24 AM.


                              [email protected]

                              1969 2002 racecar
                              1989 M3 racecar
                              e39 Touring

                              Comment

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