Announcement

Collapse
No announcement yet.

Lower A-arm Design Project

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

  • Lower A-arm Design Project

    Some food for thought. Sketch in your ideas. I'm setting up to digitize the geometry.
    35
    weld on
    45.71%
    16
    bolt on (tricky)
    31.43%
    11
    new subframe
    22.86%
    8
    current build: 95 wagon, completed build: 95 sc1 to DOHC

  • #2
    Re: Lower A-arm Design Project

    Each has its advantages depending on the application. I'm stuck with a bolt on using the factory pickup point at the swaybar and the lca to frame locations to with in something like 20mm by the SCCA rule book.
    If the rule book wasn't a limiting factor a custom subframe would be the key but the added cost would probably make it unobtainable or most leaving a weld on as more probably the best for the masses.
    Jonathan
    Just a guy with a thing for tubeframes and motorswaps...
    Saturns, I have them, too many of them actually
    sigpic

    Comment


    • #3
      Re: Lower A-arm Design Project

      For example:

      current build: 95 wagon, completed build: 95 sc1 to DOHC

      Comment


      • #4
        Re: Lower A-arm Design Project

        I was thinking of exactly what you just drew. The only thing I would like to mention for consideration is the question of whether or not we want to take advantage of this part to raise the front roll center.
        [16:02] Ferrari166mm: so you&#39;re finally getting into real cars.<br />[16:02] adamkob32: I&#39;ve just had enough of racing a 100HP nutsack
        <br /><br />

        Comment


        • #5
          Re: Lower A-arm Design Project

          Originally posted by DasPirate
          I was thinking of exactly what you just drew. The only thing I would like to mention for consideration is the question of whether or not we want to take advantage of this part to raise the front roll center.
          How would you reposition the pivot to do that? What effect does moving it out 1" have? Probably could move it up since we are all using drop springs of some sort.

          I was thinking of using the same Lord Dynaflex rod ends I used for my torque struts. They make male threaded ones which would work better with our A-arm weldment.

          current build: 95 wagon, completed build: 95 sc1 to DOHC

          Comment


          • #6
            Re: Lower A-arm Design Project



            Obviously you'd need to check with a motion model if this would work... but I'm thinking small bracket that bolts to front swaybar mounts which contains front LCA mounting points. Much more resistant to toe change.
            ilostmysocketwrench | Bentra Motorsports Blog | Bentra Motorsports Videos

            Comment


            • #7
              Re: Lower A-arm Design Project

              Originally posted by hein
              Originally posted by DasPirate
              I was thinking of exactly what you just drew. The only thing I would like to mention for consideration is the question of whether or not we want to take advantage of this part to raise the front roll center.
              How would you reposition the pivot to do that? What effect does moving it out 1" have? Probably could move it up since we are all using drop springs of some sort.

              I was thinking of using the same Lord Dynaflex rod ends I used for my torque struts. They make male threaded ones which would work better with our A-arm weldment.

              Moving it out 1" might change the instantaneous roll center at ride height or not depending on how the A-arm is oriented at ride height. Two ways to positively increase the roll center are raising the pivot at the subframe and lowering the ball joint (this would involve using a different ball joint with a longer stud or a modified knuckle. I imagine we'd want to see what this will do to bump steer.

              I'm also wondering why we want to increase the front track width. That would be the net result of moving that pivot out, would it not? It would surely also increase the kpi.

              It seems like the proper way to go about this is to measure where all of the suspension pivots are at ride height and see where we want to go with the geometry.
              [16:02] Ferrari166mm: so you&#39;re finally getting into real cars.<br />[16:02] adamkob32: I&#39;ve just had enough of racing a 100HP nutsack
              <br /><br />

              Comment


              • #8
                Re: Lower A-arm Design Project

                I think ProDrawin has a better idea. It might make swaybar issues. but overall we already know they are sound parts of the subframe to be bolting to.
                It's not my fault, blame the radiation.

                Comment


                • #9
                  Re: Lower A-arm Design Project

                  What Travis has shown is how I've looked at this before with the limitations of changing the mounting points. The sway bar is so large in part because its both sway bar and trailing link, by providing the triangulation with the a-arm extending forward there is no need for such a large swaybar. Now we would be free to use a circle track style interchangeable bar with standard ends. Mounting the bar in an extension of what we would need to fabricate to mount the a-arm to the existing swaybar pickup. For all the autocrossers and track heads you could have 4 or so different diameter bars to swap out of the bearing mounts to tune the car to the track conditions of the day.

                  On a side note, the old ICY team at one point did something like this with independent trailing arms of some sort with a smaller swaybar or possibly no swaybar at all. The information I have is sketchy from a friend who saw it in person at a factory training facility years ago. I talked with a couple of the guys from ICY and they were welcome to a couple of us going to their facility to pick over what information they still had left over from all those years back. They cautioned me that much of what they had would be way outdated in design by this time. But there is still a chance that something might be usable to us.
                  Jonathan
                  Just a guy with a thing for tubeframes and motorswaps...
                  Saturns, I have them, too many of them actually
                  sigpic

                  Comment


                  • #10
                    Re: Lower A-arm Design Project

                    I like hein and joe's replacement much better. At least you'd have the ability to get some caster into the setup, and also mount the lower control arm higher. Maybe even atop the subframe instead of where the factor location is. You could also easily widen the front track some as well making more clearance for bigger tires.

                    --Adam
                    2002 Subaru WRX - 2012 Yeti SB66 MTB

                    http://www.facebook.com/adam.koback

                    Comment


                    • #11
                      Re: Lower A-arm Design Project

                      Caster can be built into either system, can it not? Moving the ball joint foreward/back can be tweaked with the length of the 'links'.
                      It's not my fault, blame the radiation.

                      Comment


                      • #12
                        Re: Lower A-arm Design Project

                        Originally posted by ZombieSatty
                        Caster can be built into either system, can it not? Moving the ball joint foreward/back can be tweaked with the length of the 'links'.
                        It looked like you guys wanted to retain the stock lower control arm and most of the swaybar for the easier setup. Wasn't sure.

                        --Adam
                        2002 Subaru WRX - 2012 Yeti SB66 MTB

                        http://www.facebook.com/adam.koback

                        Comment


                        • #13
                          Re: Lower A-arm Design Project

                          I think the idea was to still fabricate an A-arm setup, but use the stock LCA mounting position and a fab'ed bracket bolted to the swaybars brackets used to be for the front arm.

                          Another idea...
                          for something on the cheap, or as a proof of concept. The swaybar could be cut right before it mounts to the frame, then add a round section of tubing for a bushing. It could then be used as that front arm, provide that bracket is made. Literally making the arm look exactly what ProDarwin drew up.
                          It's not my fault, blame the radiation.

                          Comment


                          • #14
                            Re: Lower A-arm Design Project

                            Originally posted by ZombieSatty
                            I think the idea was to still fabricate an A-arm setup, but use the stock LCA mounting position and a fab'ed bracket bolted to the swaybars brackets used to be for the front arm.
                            This. What I have shown is an A-arm. Stock sway-bar would be trashed.
                            ilostmysocketwrench | Bentra Motorsports Blog | Bentra Motorsports Videos

                            Comment


                            • #15
                              Re: Lower A-arm Design Project

                              I was trying to get a couple people to do this about a year ago. Just seemed to die off. I really liked the idea of A-arm, but wasn't sure about it. So I found a control arm that was tubular in an oval shape. It had the single mounting point on the sub frame with adjustable ball joint mount. I can't find it anymore, but wondered if that would be a benefit? Maybe use the stock mounting location on the subframe, but reinforce it in some manor that just about anyone could do without a welder. Drill spot welds, have new mount, and bolt on? Just an idea, but welding would be much preferred.

                              Also found this....


                              I am just wondering if running such a thing would be as good as the A-arm. I know this was about the A-arm, but wanted to hear what the engineers say.
                              Ian---The Fat Ass

                              1995 SL2-High compression engine FOR SALE
                              2010 Chevy Cobalt SS- tuned with plenty of goodness
                              2002 SC2-New daily
                              2017 Kawasaki Ninja 650 KRT- got a stupid deal
                              2003 Ford Taurus SES- free daily beater

                              Comment

                              Related Topics

                              Collapse

                              There are no results that meet this criteria.

                              Working...
                              X