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  • S-chassis alignments!!!

    I'd kill for even 5 degrees of caster on the Sentra. The last time i had it aligned...I could only pull off 1.5 degrees of caster...lol
    Between rides...unless you count a WD21...


  • #2
    1.5?? I wonder if that's due to the FWD layout. More caster on it might load or unload the suspension while trying to plant power.

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    • #3
      Yeah it is due to the FWD layout. Usually you can put to use about 4-5 degrees of caster, but anymore than that and the chassis starts to react to input weird. I was hoping for at least 2-2.5 degrees stock though...but when we threw it on the Hunter rack...1.5 was it...
      Between rides...unless you count a WD21...

      Comment


      • #4
        I forgot what was in this thread before, but I was wondering if anyone had any input on my alignment plans:

        Front:
        -3.0 camber
        0 toe
        7 caster

        Rear:
        -2.0 camber
        1/16" toe-in

        Notes:
        - S14
        - Spring rates will be around 550lbs F, 450lbs R (basically 10k/8k), supplemented by a Largus 32mm front sway bar and no rear bar
        - Tires are RE-01Rs, 245/40/17 all around on 17x9 +17 wheels

        There were two things I was wondering about. One, should I maybe run more front camber? IIRC, some of the more hardcore auto-x guys like Ace and JRho have been running as much as -4.0 or more, and I'm thinking that -3.0 might not be quite enough, especially without a rear bar to help the car rotate. I'm planning on using the car mostly for auto-x and definitely a few track days, and I don't drive it on the street much, except to events, which could be 2 or more hours of highway driving. I don't think tire wear should be an issue as long as the toe remains pretty much zeroed. Which brings me to my next question: rear toe.

        I have no idea how much toe I should run in the back. 1/16" seems like a good place to start, but don't S-chassis rear suspensions toe-in on compression? I would think that possibly going with zero would both help the car rotate off-throttle and help with tire wear in the rear by only toeing-in on acceleration. Am I on the right track?

        If anyone has any suggestions, please post them, I'm interested in what more experienced people would recommend.

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        • #5
          I've run an alignment pretty close to that but with 0.2* degree less camber in both front and rear and it resulted in pretty even tire temps. This was for track days, btw. I think more front camber helps in autox because at higher steering angles the mac strut setup gets a little goofy. I was just reading the GRM article about Jason Rhoades' STS car and he mentioned that the rear suspension cambers in quite a bit under compression and hence didn't need much static camber to work well. When I posted about alignment on FA he recommended 0 front toe and very slight rear toe-in, as you mentioned.

          All that said, it would be good to hear from people who have looked at what the front and rear suspensions do under compression in terms of camber and toe. I was planning to do this when I revamp my suspension.
          ~1992 240SX, SR20/Koni track day car
          ~2016 M3, daily driver

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          • #6
            I purchased a Firestone lifetime alignment for the S13, figuring they could get close if prodded and I'm likely to make TONS of suspension changes/upgrades over the tears.

            When I had it aligned, they weren't able to get the rear left toe in spec, and it was set to 1.45°. Rear right toe was also out, set to 0.89°. Thoughts? Maybe this is why my ass never became happy!

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            • #7
              Since my post was wiped as of the change to Vbulletin, here is what I ran all last year. For the most part the alignment felt great when I was NA and ran on the 225/45/17 RE-01R's.

              Front:
              Camber -2.5
              Toe 0
              Caster 7

              Rear:
              Camber -2.0
              Toe 1/16 toe-in

              For next year, I'll be making a few changes. Most of the changes will be due to making an extra 100+ whp and that I'm running alot more tire. Also the car hunted on the road way WAY to much with zero toe up front.

              Front:
              Camber -1.5 to 2 (limited to what I can get with the new housings)
              Toe 1/16th toe-in
              Caster 8.5-9 (to compensate for the lack of camber)

              Rear:
              Camber -1.5
              Toe 1/8 toe-in (to assist in keep the back end plated on corner exit)
              -Monty

              Comment


              • #8
                The front housings have that much of an effect on camber? -2* isn't very much for DOT R comps on a strut suspension. I'm already running more than that with street tires and my tire temps are even to the degree I'd like. Have you tried maxing out your camber plates and only got -2*?
                ~1992 240SX, SR20/Koni track day car
                ~2016 M3, daily driver

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                • #9
                  Richards first batch of strut housings don't allow for that much camber, which is great if your wanting to maximize the inner tire/strut clearance. All the newer housings he's building offset the upper hole to allow for more camber, but come at a cost of wheel/strut clearance, so I'm ok with the loss of camber.

                  The more tire you run, the less camber you need *in theory*. With 2.5 degrees of camber up front and the 225 width RE01R's I was seeing optimal temps and good wear across the tires. For a 255-275 width tire 2 degrees should be enough.

                  I'll back my talk with facts once I get a few track days in with the new setup. I do use a longacre tire pyrometer to measure tire temps after every session until I have tire pressures right and to help with any last bit of alignment tweeks that need to be made. This was a must when I ran hoosiers on the sentra, those tires were so sensitive to alignment and tire pressures.
                  -Monty

                  Comment


                  • #10
                    Hm, I'd never heard that. What's the basis for wider tires requiring less camber?

                    I also would expect R comps to need more camber than street tires because they generate more grip, and thus more body roll, moving you away from the nice part of the mac strut camber curve.

                    As always though, experience trumps e-guesses, and I'll be really interested to see how it all works out for you
                    ~1992 240SX, SR20/Koni track day car
                    ~2016 M3, daily driver

                    Comment


                    • #11
                      I'll get back to the wider tires/less camber theory when I have more time to think it through... now that you make me think of it, I'm drawing a blank .

                      As for the additional grip of the R-compound tires and body roll, that's what stiffer springs and rollbars are for .
                      -Monty

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                      • #12
                        Originally posted by McCoy View Post
                        I'll get back to the wider tires/less camber theory when I have more time to think it through... now that you make me think of it, I'm drawing a blank .

                        As for the additional grip of the R-compound tires and body roll, that's what stiffer springs and rollbars are for .

                        Indeed, I just meant if everything else is kept constant. Jason Rhoades was a big proponent of front camber on his STS car, I think it ran -4.5* on street tires. Not sure what alignment he had once he went to the big Hoosiers though.
                        ~1992 240SX, SR20/Koni track day car
                        ~2016 M3, daily driver

                        Comment


                        • #13
                          Originally posted by turtl631 View Post
                          Indeed, I just meant if everything else is kept constant. Jason Rhoades was a big proponent of front camber on his STS car, I think it ran -4.5* on street tires. Not sure what alignment he had once he went to the big Hoosiers though.
                          I was just looking at his SM build thread the other day on FA. I think his alignment was something like:

                          Front:
                          -4.0 camber
                          1/16th toe out
                          Some amount of caster

                          Rear:
                          -2.25 camber
                          3/4" toe-in total (!)

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                          • #14
                            A good autocross alignment is not the same as a good track alignment. I've been there and done that with my NX2000 and finally stopped autocrossing mainly due to the fact I wanted to focus more on track days and setting the car up properly it.

                            There is a thing as to much camber, this is why it's important to use a tire pyrometer to make sure the alignment is working for you and not against you... or the life of your tire
                            -Monty

                            Comment


                            • #15
                              Originally posted by McCoy View Post
                              Since my post was wiped as of the change to Vbulletin, here is what I ran all last year. For the most part the alignment felt great when I was NA and ran on the 225/45/17 RE-01R's.

                              Front:
                              Camber -2.5
                              Toe 0
                              Caster 7

                              Rear:
                              Camber -2.0
                              Toe 1/16 toe-in

                              For next year, I'll be making a few changes. Most of the changes will be due to making an extra 100+ whp and that I'm running alot more tire. Also the car hunted on the road way WAY to much with zero toe up front.

                              Front:
                              Camber -1.5 to 2 (limited to what I can get with the new housings)
                              Toe 1/16th toe-in
                              Caster 8.5-9 (to compensate for the lack of camber)

                              Rear:
                              Camber -1.5
                              Toe 1/8 toe-in (to assist in keep the back end plated on corner exit)
                              In the front I would run toe-out. Toe out is supposed to help the car turn in and change directions better. It is definitely a good idea to give it a ****load more caster to compensate for the loss of camber. The specs I am currently running on my s-13 are:

                              FRONT:
                              -2.8 camber
                              +7 caster
                              0 toe
                              REAR:
                              -2.0 camber
                              1/16" total toe in
                              3/8" shorter trac arms

                              I haven't noticed any serious "hunting" problems with my toe and the shorter trac arms really seemed to help the car bite off the corners. I think for my next alignment I will run:

                              FRONT:
                              -3.0 camber
                              +7.5 caster
                              1/16" total toe out
                              REAR:
                              -2.0 camber
                              1/16" total toe in
                              Shorten the trac arms another 1/4" or so
                              function > form
                              1990 240sx fastback: IN PROGRESS

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