Announcement

Collapse
No announcement yet.

Alignment Suggestions

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

    Alignment Suggestions

    Hi Guys,



    I'm looking for some alignment suggestions. I've been to the track a few times over the last couple years. The car has been great and I've been able to gradually cut down my times. I've never got a proper alignment done prior to the track days and I'm not sure what they are exactly. When I bought the car a few years ago it came with the alignment sheet pictured below. The car has handled find and is predictable and fun.





    Original Setup
    -Racing Dynamics Springs(green coating but most of it has rubbed off)
    -15x8 +15
    -205/50/15 Dunlop Star SpecsII


    I did a major overhaul this spring and added the below
    -fcab offset bushing
    -eccentric tabs to the rear subframe
    -new sway bar endlinks

    I did not do an alignment prior to installing the new parts.

    My front camber is fixed since I don't have plates yet. Should I adjust my rear camber based on my front camber settings? Currently the car has a -1.3 in the front and -2 in the rear which I've seemed to enjoy so far. Also should I keep my toe settings the same? What can I expect in terms of the new caster?





    Thanks

    Ivan
    Last edited by iPee; 08-22-2017, 10:48 AM.

    #2
    So generically, for track use, -4 degrees camber front and rear's a decent starting place.

    But it makes for less pleasant street manners.

    What you've listed is a good 'sporty street' setup- a little more camber in the rear, about
    zero toe.

    Don't toe- out in the rear. It's just no fun anywhere.
    It's easy to toe- out in the front, and see if you like the improved turn- in
    or hate the twitchiness.

    Don't camber the front more than the rear- it increases the chance of sudden, snap
    oversteer. DO go as much as you can, radials suck up static camber.


    for starters,
    t
    now, sometimes I just mess with people. It's more entertaining that way. george graves

    Comment


      #3
      Originally posted by TobyB View Post
      So generically, for track use, -4 degrees camber front and rear's a decent starting place.

      But it makes for less pleasant street manners.

      What you've listed is a good 'sporty street' setup- a little more camber in the rear, about
      zero toe.

      Don't toe- out in the rear. It's just no fun anywhere.
      It's easy to toe- out in the front, and see if you like the improved turn- in
      or hate the twitchiness.

      Don't camber the front more than the rear- it increases the chance of sudden, snap
      oversteer. DO go as much as you can, radials suck up static camber.


      for starters,
      t
      Wow, really? Most of that was contrary to what I thought is "normal" for these cars. I've been running zero toe in the front (or a bit toe out), slight toe in on the rear (for high speed stability) and about 2.5 degrees camber in the rear and 1.8 in the front. I was told by the last place I got an alignment (JMP in van nuys, CA - they race prep and race e30s etc all the time) that I didn't want a lot of rear camber because that'll result in more oversteer, of which the s52e30 is already very susceptible.

      Now granted this is on street tires (DZ2s, moving to R888s), and I still do a fair bit of street driving, so maybe everything changes when you move to slicks?

      Just curious because I've been fighting so much oversteer (I also definitely need to learn to tame my right foot)
      '89 325i OBD2 S52 BUILD THREAD
      Shadetree30

      Comment


        #4
        A good baseline setup is:

        Front
        8.2-9.8 degrees of positive caster. Depends on driver here. I personally run on the high end since the short wheel base makes the rear want to come around quite quickly. High caster has saved my ass countless times bringing her back around. If you do run no rear bar, you may have to go up in spring rates a little to help hold the rear up a little more, and adjust dampening accordingly.

        0 Toe (if the high caster is killing turn in or creating some understeer mid corner you can add a little toe out)

        -3.5 degrees camber (use probe pyrometer and adjust accordingly)

        Rear (if you have adjustment)
        -2.2 degrees camber (same as front. pyrometer)

        1/8" toe in (don't even think about changing this one)

        Other thoughts:
        -I find that running no rear sway settles the rear of the car down a lot. If you have one, you may want to try unhooking it for a session or two. Don't forget that you also have front sway bar settings that you can use to move grip from one end of the car to the other.

        -Much of the success of your settings are going to depend on the roll center of the car, ride height, and very much so on dampers and spring rates. Get yourself a good probe pyrometer and take good notes. This is the key to setting up your alignment and suspension for your car and driving style.

        -Tire pressures are for FINE TUNING grip. It's not autocross out there. Knocking them down to 20 psi is gonna make it FEEL like you have more grip, but that is just a bandaid for an improperly setup car.
        sigpicLevel Motorsport: www.levelmotorsport.com

        Instagram: https://www.instagram.com/levelmotorsport/

        Facebook: https://www.facebook.com/LeVelIndustries/?fref=ts

        Comment


          #5
          Hmm, op, you didn't say initially that you were fighting oversteer, nor that you had
          far too much power ;)
          I was thinking along the lines of a stock powerplant, with relatively neutral initial handling.

          The rear camber is a pretty sensitive balance on these cars between cornering grip
          (more camber) and traction grip (less). Making matters worse, rear squat under power
          adds rear camber right when you don't want it.

          So if you're fighting oversteer on corner exit/ power application, YES, take rear camber
          out.
          However, this will reduce your mid- corner grip, and trend the car towards steady- state
          high cornering load oversteer. Moderate power application will then reduce this, as it adds rear squat,
          and thus, camber. This will favor a 'slow in, fast out' driving style.

          Totally agree about the rear bar- unhook it and see. It suffers from binding, too,
          which only makes things worse.

          And if that's not enough, softening the rear springs often helps, too.

          DO be careful at first with a car with less rear than front camber- it will have
          a tendency to lose the rear end first, and be more 'trailing throttle oversteer' prone.

          And what works for you might be a bit different than what works for us...

          t
          now, sometimes I just mess with people. It's more entertaining that way. george graves

          Comment


            #6
            Appreciate the input guys.
            IIRC I was not fighting oversteer, the car handled pretty neutral as far as I was concerned. I think I'm still too new to process some of these aspects during a turn. All I know is that it was a blast. The car is stock powerplant, M42.

            Going for an alignment tomorrow, and track day will be on Sept 5. I'll report back then.

            Comment


              #7
              I was told by the last place I got an alignment (JMP in van nuys, CA - they race prep and race e30s etc all the time) that I didn't want a lot of rear camber because that'll result in more oversteer, of which the s52e30 is already very susceptible.
              You can see why I was confused... m42 in an e30 is pretty different to s52!

              For an M42, take all the camber you can get, and match front to rear.
              That should maximize lateral grip.

              Then balance with bars and springs, if need be.

              t
              now, sometimes I just mess with people. It's more entertaining that way. george graves

              Comment


                #8
                Toby, with -4 degrees camber in the rear, are you not destroying tires fast? I tried -3 with 1/8" toe in the rear of my car and had camber wear to the cords in two 15 minute sessions, lol!
                OP, a hell of a lot depends on the tires you are using as well. I run 275/35r15 A7's square, and I end up with a setup much closer to what you'd expect running a bias ply tire. I say use the shit out of a pyrometer and log lap times until you get it right.
                sigpicLevel Motorsport: www.levelmotorsport.com

                Instagram: https://www.instagram.com/levelmotorsport/

                Facebook: https://www.facebook.com/LeVelIndustries/?fref=ts

                Comment


                  #9
                  a hell of a lot depends on the tires you are using as well. I run 275/35r15 A7's square,
                  Err, that's not stock...

                  Yes, in fact, it ALL depends on tire/rim choice and tire compliance.
                  If the OP is running a bias race slick, I'm fulla shit, and he need about -.5 degrees in
                  back, 0 in front.

                  I'm coming from 225-45 radials that have to be squeezed onto 15x7" rims.
                  So they move a lot.

                  The pyrometer is a good friend. Unfortunately, you ALSO need a crewmember
                  to stab tires when you come flying in hot... as 30 seconds makes a difference.
                  But consistency is paramount- the surface-to-core temperature is constantly changing,
                  and so to get meaningful data, you HAVE to do it the same time, every time.
                  To get the most useful data, you have to do it as soon as you slide to a halt.

                  There was some IR video of Button a number of years back, when his engine blew up
                  and caught on fire. The punters were watching the engine fire in IR,
                  but the truly interesting thing was to watch his tire surface temperatures flare
                  as the car sat.

                  t
                  now, sometimes I just mess with people. It's more entertaining that way. george graves

                  Comment


                    #10
                    I run 4.2* camber front, 2.8* rear. No adjustment in the rear on purpose, but 2mm total out in the front and 2.5mm total toe in rear. I haven't done a caster sweep with this setup, but I don't think I'm very high, I put centered bushings back in it to help wheel position. Steady state trends towards a little free, turn-in really free on 235/40 Z2, but we are running a rear bar with lots of rake (unfortunately). Converting to rear coilover now to add adjustment to fix the rake, but worried about having to fix toe when we do that. Lot's of stuff to consider!

                    For OP, I would get camber plates ASAP... But for now just run a little toe out in the front, a little toe-in in the rear, and leave the rear camber as is.
                    - '88 m54 coupe

                    <3

                    Comment

                    Working...
                    X