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    SCCA SM class rule clarification

    For all the autocrossers out there....

    From 16.1.E of the 2009 rulebook, on p. 102 of the downloadable version:

    ****
    E. Suspension components are unrestricted as long as they use the
    original attachment points. For the purposes of this rule,
    “suspension” is defined as any item that is designed to move
    when a wheel is deflected vertically. This includes shocks and
    struts, control arms, steering knuckles, uprights, etc., but not tie
    rods, steering racks, and subframes. In addition, shock absorber/
    strut upper mounts are to be considered suspension
    components.
    ****

    Stock, the 325i uses an attachment point on the control arm to transmit suspension movement to the swaybar (both F&R). On an BMW E30 M3, the front swaybar uses the strut housing tube to transmit vertical force, NOT the control arm. I want to modify my strut housing to mimic the E30 M3 swaybar point.

    Is the rule above specifically pointed towards attachment points of the suspension to the body of the car....or suspension points to each other (ie. swaybar to control arm / strut housing) or BOTH? If both, I believe my proposed modification would violate the rules....so before I cut & weld I want to ensure I'm not classing myself out of even SM.

    Thanks,
    John
    1990 BMW 325i

    #2
    From what i understand, that modification is fine. ive got mine done, and was told its even legal in DSP


    Originally posted by vlad
    Do you know anybody else who built that many bad ass E30s?

    Comment


      #3
      My reading of that rule would disallow your proposed change.
      The car makes it possible, but the driver makes it happen.
      Jim Levie, Huntsville, AL

      Comment


        #4
        Great, thanks. Someone in my region replied to my local post as well, and said the same.....so I'm good to cut & weld.

        Thanks,
        John
        1990 BMW 325i

        Comment


          #5
          On a somewhat related note, what class does moving pickup points place you in?

          XP? Or a straight modified class?
          Need parts now? Need them cheap? steve@blunttech.com
          Chief Sales Officer, Midwest Division—Blunt Tech Industries

          www.gutenparts.com
          One stop shopping for NEW, USED and EURO PARTS!

          Comment


            #6
            xp would be my guess.


            Originally posted by vlad
            Do you know anybody else who built that many bad ass E30s?

            Comment


              #7
              As a follow up to that, just to make sure I'm reading it correctly, we could move the rear subframe up (through shorter mounts for instance) and be legal.

              The advantage being, effectively raising the pickup points for the TAs while lowering ride height and attempting to keep a more favorable rear geometry.

              But since the diff mounts to the subframe, would we have to then space it back down? And would that interfere with the subframe. Hmmmmmmmm
              Need parts now? Need them cheap? steve@blunttech.com
              Chief Sales Officer, Midwest Division—Blunt Tech Industries

              www.gutenparts.com
              One stop shopping for NEW, USED and EURO PARTS!

              Comment


                #8
                or make group n rear ends.

                adjustable control arms are legal too


                Originally posted by vlad
                Do you know anybody else who built that many bad ass E30s?

                Comment


                  #9
                  Originally posted by Joe318is View Post
                  or make group n rear ends.

                  adjustable control arms are legal too
                  Group N rear ends? Like the old E30 M3 stuff where they modified the angle? Got any links for that.

                  The control arms is interesting, I have been chatting with a guy from the GRM forum who has a really slick set of control arms he built. I'll post the pic he sent me when I get home.
                  Need parts now? Need them cheap? steve@blunttech.com
                  Chief Sales Officer, Midwest Division—Blunt Tech Industries

                  www.gutenparts.com
                  One stop shopping for NEW, USED and EURO PARTS!

                  Comment


                    #10
                    i think it was group n. cant find pics. the are trailing arms with spherical rod ends to mount them to the subframe


                    Originally posted by vlad
                    Do you know anybody else who built that many bad ass E30s?

                    Comment


                      #11
                      That's what this guy did, effectively gives you adjustable wheelbase and toe. Then I suppose use an eccentric bolt in the mounting spot for camber adjustment.
                      Need parts now? Need them cheap? steve@blunttech.com
                      Chief Sales Officer, Midwest Division—Blunt Tech Industries

                      www.gutenparts.com
                      One stop shopping for NEW, USED and EURO PARTS!

                      Comment


                        #12
                        Originally posted by z31maniac View Post
                        As a follow up to that, just to make sure I'm reading it correctly, we could move the rear subframe up (through shorter mounts for instance) and be legal.

                        The advantage being, effectively raising the pickup points for the TAs while lowering ride height and attempting to keep a more favorable rear geometry.

                        But since the diff mounts to the subframe, would we have to then space it back down? And would that interfere with the subframe. Hmmmmmmmm
                        my ix is already like this. stock ix bushings are about 1/2" taller pushing the subframe down for the 4x4 ride height, so with standard E30 AKG bushings my subframe is moved up. I spaced the diff down with some thick washers, it doesn't interfere with the diff at all, although I had it in there with no washers for 6 years without a problem.
                        Build thread

                        Bimmerlabs

                        Comment


                          #13
                          i think the SM rules do not allow you to move the subframe at all. infact, even the IE style camber/toe adjusters are illegal. which is very annoying, because in the spirit of the rule, they should be legal since they arent designed to provide geometry adjustment, only alignment.

                          edit: and infact, a completely tubular/adjustable trailing arm is legal even though it is countless times better than the illegal adjusters.
                          Last edited by guibo09; 03-05-2009, 11:54 AM.
                          90 E30 325i

                          Comment


                            #14
                            ^I think by that rule portion up there, moving the subframe is completely legal. But if eccentric bolts are illegal, how could you get some camber adjustment back?

                            Originally posted by nando View Post
                            my ix is already like this. stock ix bushings are about 1/2" taller pushing the subframe down for the 4x4 ride height, so with standard E30 AKG bushings my subframe is moved up. I spaced the diff down with some thick washers, it doesn't interfere with the diff at all, although I had it in there with no washers for 6 years without a problem.
                            Ahhhh good to know. I know I'll need to take a look after I get the swap done, but do you have any idea how much you could raise the subframe without it interfering with driveshaft? The rear subframe has a "hole" that the driveshaft passes thorugh correct? I can't picture it in my head at the moment.

                            IE, if you were to move the subframe up you start to lower the clearance between the driveshaft and the bottom of the hole in the subframe.
                            Need parts now? Need them cheap? steve@blunttech.com
                            Chief Sales Officer, Midwest Division—Blunt Tech Industries

                            www.gutenparts.com
                            One stop shopping for NEW, USED and EURO PARTS!

                            Comment


                              #15
                              Originally posted by z31maniac View Post
                              ^I think by that rule portion up there, moving the subframe is completely legal. But if eccentric bolts are illegal, how could you get some camber adjustment back?
                              how are you reading it?

                              the way i read it is that the subframe is not a suspension component. it is therefore not free to be changed. the trailing arm to subframe connection is considered a suspension attachment point, and under sm rules, it may not be moved. the eccentric bolts move the attachment point, and are therefore illegal.

                              am i missing something?
                              90 E30 325i

                              Comment

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