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  • Rear LCA boxing (good or bad idea)

    I have my rear LCA's off the car. I need to replace the ball joints.


    I was thinking about boxing in the lower portion of them. IS this a good or bad idea?

    Is it necessary, or will i see any benefit from it? Or will it just add weight.


    On a side note, is there any roll center correction for the rear that does not involve modifying the spindles?

    Possible "defsport" style for the rear?
    1992 LS13
    385whp/370tq

  • #2
    Go ahead and box them. Adding strength never hurts. 1/8" should be good.

    Comment


    • #3


      Odd shot sorry its blurry but this is an s15 RLCA, its similar to s14 side by side minus the gussets and reinforcements. Nismo RLCA will probably also share these same qualities. Completely safe to do this on your own after you remove the bushings I'd say.

      Comment


      • #4
        1/8" is way thicker than you need. use whatever thickness plate the RLCAs are made from- it's like 1/16" or so IIRC.

        As for roll center correction, it's not as simple as the front due to the multitude of pivot points in the back.

        since you're welding on the thing anyway, you could alwys cut out the old ball joint and weld in a sleeve to install a longer adjustable ball joint like they use on roundy-round cars. Coleman Machine and UB Machine sell all kinds of parts for that..
        http://ubmachine.com/monoballhousings.html
        Originally posted by SoSideways
        I don't care what color they are as long as they are LONG AND HARD.
        '04 G35 Sedan 6MT- The DD
        '96 240SX- The Track Toy

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        • #5
          http://www.nissanroadracing.com/showthread.php?t=1568
          ^here is another thread on the same subject... if you are using rubber bushings or even poly there might not be much of a benefit since the bushings will deflect before anything happens to the arms anyway.

          Also if you happen to hit anything it's nice to have LCAs that "give" to limit the damage to other suspension components.
          I know this^ has saved me before.
          Last edited by marcinko; 01-12-2012, 03:25 PM.

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          • #6
            16 ga or so should be fine to add some strength to them. 1/8" is overkill.

            That said, the RLCA being a weak point is nice if you bump into something. Better to replace a RLCA than have a tweaked chassis.
            '18 Chevrolet Volt - Electric fun hatch for DD duty!


            DefSport Koni Sleeve and Spring Perch Buy!!!
            http://www.nissanroadracing.com/showthread.php?t=5902

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            • #7
              Oh yea, to add - bushing deflection is probably 1000x more than the RLCA bending. I wouldn't bother if you're running anything but delrin or spherical in the RLCA.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!


              DefSport Koni Sleeve and Spring Perch Buy!!!
              http://www.nissanroadracing.com/showthread.php?t=5902

              Comment


              • #8
                Does anyone currently sell sphericals or delrin bushings for the LCA in the rear? I have not seen them anywhere.


                Also, why is it not as simple as the front? If i welded on a tube and installed a spherical bearing like the front, would that be disastrous?

                I am a engineering student here, and have little to no knowledge on advanced suspension theory like this. Is there any tech documents or books you would recommend i pick up to research this topic?
                1992 LS13
                385whp/370tq

                Comment


                • #9
                  A longer ball joint shank on the LCA increases camber gain on suspension travel a lot and is general considered disadvantageous.

                  So in short, no, there is no roll center correction like the front besides buying subframe-lifting bushings like PSM or SPL. Not much is needed anyway.
                  Support innovation, buy from companies that design their own parts!

                  Friends don't let friends buy knock-offs.

                  Suspension before power.

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                  • #10
                    16 GA is pretty flimsy......I wouldn't? Even trust 14ga. I work with the stuff all the time. I'd rather have bracing be overkill than too little.

                    Comment


                    • #11
                      As has been said many times in this thread, brace it to make it stronger yet weak enough to collapse. 16 ga. would be perfectly fine especially with a dimple die or two depending on how you lay it out.

                      Comment


                      • #12
                        Originally posted by shiftdrift View Post
                        16 GA is pretty flimsy......I wouldn't? Even trust 14ga. I work with the stuff all the time. I'd rather have bracing be overkill than too little.
                        the LCA itself is probably only 14 or 16 ga to begin with. Adding gussets stronger than the rest of the part is only adding weight, as they'll simply collapse somewhere else..
                        remember, you're not going to have THAT much force on these things. look at the dinky mounts holding them to the subframe and think about how much stress they can hold. there's no point in building a control arm that can hold up a semi when your mounting points will only hold a civic. you're just adding weight, and moving the breaking point from something cheap and easy to replace (the LCA) to something expensive and difficult to replace (subframe, or worse- the mounts that attach the subframe to the chassis.)
                        Originally posted by SoSideways
                        I don't care what color they are as long as they are LONG AND HARD.
                        '04 G35 Sedan 6MT- The DD
                        '96 240SX- The Track Toy

                        Comment


                        • #13
                          Don't tease my welding, but here's how I did mine. The stuff I hate laying around was slightly thicker than the arm itself. Did it make any difference? hard to say. I did it when they were off the car.

                          'Slicks on a car show me you care - broken axles show me you're trying'
                          [I]Nitrous Rental Cars - Turbo Festivas - Vehicular Lunacy[/I]
                          [SIZE="3"][B][url]www.sloppymechanics.com[/url][/B][/SIZE]

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                          • #14
                            Cody, thankyou for that picture!

                            Can I ask you about the zerk fittings? Did you just drill a hole and tap in the fittings? Did your bushings (assuming poly?) have a spot designed for the zero fitting?


                            Are the poly or rubber bushings designed to stay stationary in comparison to the lca, such that the metal sleeve rotates within the inside diameter of the poly?


                            I ask because I am trying to make some home made delrin inserts. I was going to drill and tap into the delrin and keep the surface between the delrin id an the bronze od greased using the zerk. Is this the correct concept?
                            Last edited by Air; 01-13-2012, 05:35 PM. Reason: Iphone
                            1992 LS13
                            385whp/370tq

                            Comment


                            • #15
                              Originally posted by Air View Post
                              Cody, thankyou for that picture!

                              Can I ask you about the zerk fittings? Did you just drill a hole and tap in the fittings? Did your bushings (assuming poly?) have a spot designed for the zero fitting?


                              Are the poly or rubber bushings designed to stay stationary in comparison to the lca, such that the metal sleeve rotates within the inside diameter of the poly?


                              I ask because I am trying to make some home made delrin inserts. I was going to drill and tap into the delrin and keep the surface between the delrin id an the bronze od greased using the zerk. Is this the correct concept?
                              You really won't need the zerk fitting for the Delrin, its property of self lubrication take care of the lube issues if I am not mistaken. I am in the process of making 5 sets of these with a bronze center. I had first modeled them off of the poly bushings I have sitting around (uninstalled), but they may need a few thousandths off them due to the delrin being a little less pliable than the poly.

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