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  • S13 front sub frame

    Hey everyone just wanted to put it out there this is my first post!! yeah popped the cherry!!! anyways, i have been reding the anti squat thred in this forum as I was searching for more info on the s13 platform. But Maybe Im not quite good enough with following the discussion, i am new to alot of this stuff, but I just cant find or correlate an answer to my situation. I have not touched the rear of the car but the front subframe is lowered 2 inches to fit my motor. I have a 5.0 in there. Anyways , In an effort to maybe maximize my current situation insted of lowring the rear 2 inches I figure I sIhould ask for some help. I reailize that tilting the rear subframe can reduce the s13's natural anti squat, but how does this stuff affect the front? i searched the term "lowered subframe" on google and here... not to many peeps do it so the info is lacking.

  • #2
    Wouldn't lowering the front subframe have a slightly negative effect on the suspension geometry? It seems that way in my head. I would have suggested modifying the hood instead, maybe even custom motor mounts at the most.

    Unless you chopped the front crossmember and modified it to get the lowering effect.
    Originally posted by Matt93SE
    in engrish, it's all about the length of your shaft... :P

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    • #3
      Lowering the front subframe brings the inner FLCA pivot down, which is the same thing that happens when you lower your car too much. It's worse than simple spring lowering b/c your ride height doesn't change with subframe. You start gaining positive camber even at stock height.

      In short your lowered front subframe already fvcked up the geometry without any benefit.
      Last edited by hai1206vn; 11-26-2010, 11:27 AM.

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      • #4
        hai1206vn:
        Could i adjust out my camber and to a certain extent unfudge it by getting some adjustability up front? I do plan to eventually try and bring the subframe up but its on my list of stuff to do. But with christmas i could prolly score new control arms?.....Just an idea. But thanks for the tech explanation.

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        • #5
          I'd put it back ASAP and get hood spacers for the time being. We're all trying to improve suspension geometry already. Trying to improve it after already taking 2 steps back seems like more trouble than it's worth.
          Originally posted by Matt93SE
          in engrish, it's all about the length of your shaft... :P

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          • #6
            I'd put it back to stock height if possible. I don't think you can correct that much out, and it gives lots of anti-dive to the front suspension (not a horrible thing, but does make braking not as positive with bite).

            The camber problem is that with the LCA pointing up you LOSE negative camber with roll. As in you have -3 deg, car rolls 3 deg and you lose 2 deg of camber. So you have +2 deg camber with the ground.
            '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
              The hieght issue is going to be adressed when I swap trannies. Im goin to a smaaler C$ trns which might net me my room. If it does Ill just make a cowl hood.(so redkneck ford lol) One issue though.... I am gettin FLCA's for chrisatmas, just talked to wifey bout it. you kinda lost me on the camber talk in the last post. So Im guessin I should adjust out 2 degress of camber ie -2 degerees. Ill take some pics of exactly where my whell sits if you guys dont mind lookin at it. once I get it started todaay Ill be able to get to a jack and mkae some new mounts, maybe I can gain 1/2 an inch or so ifor the short term.

              ANother Idea. Would I be better or worse to say, umm, cut the front crossmember and raise the subframe up? Ill annotate on some pics what Im gettin at.

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              • #8
                The front suspensions GAINS negative camber on the outside corner as it rolls into a corner (when properly setup). Lowering the car way too much or moving the subframe down like you did will make it start losing negative cher with any roll. Basically your outside tire kicks out old 60s muscle car style in a corner and you slowly grind through the corner. Not the fastest way to go into a corner.

                With your current setup you probably need more like -3 deg camber static.
                '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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                • #9
                  btw Def, how much front camber gain can you get from a proper setup? Any idea what the stock design gets?

                  No measurement, my eyeballing magic says I get like -0.5* over 1.5" compression (for 1" lowered from stock height, no correction).

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                  • #10
                    Never measured it out. I imagine stock height gets quite a bit more than that. Once the arm starts leveling out camber gain goes nearly flat.
                    '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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                    • #11
                      FWIW I get about this much roll for 300# front spring & progress bar on 225mm RE01R. Much softer than everybody, but -2.5* static camber seems to work. I can probably roll an extra 0.5*and still keep the front tire almost square to the ground.

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                      • #12
                        Zero camber relative to the ground isn't ideal. The tire gets really deformed on the wheel, so you want a little camber to help generate more traction when the tire gets really deformed like that.

                        My car got significantly quicker going from -2 to -2.8 deg of camber up front. I have 500 lb/in springs and a 25 mm front S13 bar that's about 10% stiffer than stock. My S13 is also lighter than most other S-chassis, so it's going to roll less for a given lateral acceleration with the same roll stiffness.
                        '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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                        • #13
                          Originally posted by hai1206vn View Post
                          FWIW I get about this much roll for 300# front spring & progress bar on 225mm RE01R. Much softer than everybody, but -2.5* static camber seems to work. I can probably roll an extra 0.5*and still keep the front tire almost square to the ground.
                          Why are those cones in mid air?

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                          • #14
                            Cuz he's Ken Block and they're doin their B-Boy thang for a new video?
                            Originally posted by Matt93SE
                            in engrish, it's all about the length of your shaft... :P

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                            • #15
                              Cuz I was pointing straight at those 2 just before that & scared the **** out of them. I'm a mushroom cloud laying mothafka.

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