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Rear end is way too tail happy. How do I get more lateral grip?

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    Rear end is way too tail happy. How do I get more lateral grip?

    Backstory: M52 swap, SRS 5 lug conversion, BC coilovers 8k/8k, 22mm garagistic front sway bar, No rear sway bar, Cheap Hankook 225x17 tires, SLR half kit front, e46 control arms, 2.91 lsd, -3.5 camber front, -2.5 camber rear, style 42's 17 x 8,


    I've kinda built the car with the idea that I can drift it and/or time attack at the minor inconvenience of adjusting rear end alignment from 0 camber to -2.5.

    Drift, the car is muy bueno, but at the grip alignment (-2.5 camber) it is tail happy enough to gain attention from a few different people at Willow Springs.

    Removing the rear sway bar helped alot, and obviously the adjustability in camber and toe was a big improvement. However even with these changes, lateral grip is whack.

    I have heard that increasing the springs rates to 10-12k might help, and wheel spacers are a last ditch effort for maximum grip .

    So Alas, how do I keep the rear end more planted during long turns?

    Imma cut off my fenders and throw some decent 235 tires on there, but let me know if spacers or springs really are the save-all solution to my problem.... Or if I am missing something all together.

    My relationship is in your hands gentlemen.

    **Sorry if I am stupid

    #2
    Take some rear camber out closer to -2.

    What is your rear toe and rear bushing setup?

    Get some decent tires - better offsets will keep you from cutting the fenders. 235 will fit later cars, 245's will fit early cars.

    Spec E30 coilover kit is a good base line 535/700 on the soft side for a track car. An 8K spring "450 lbs" Front and rear sounds like it would not handle great.

    Run a bigger front bar as possible, small to none in the rear.


    I was up above it, Now I'm down in it ~ Entropy - A Build thread.

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      #3
      "Cheap Hankook 225x17 tires"

      In the words of Adam Savage - "Well there's your problem"

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        #4
        Originally posted by e30davie View Post
        "Cheap Hankook 225x17 tires"

        In the words of Adam Savage - "Well there's your problem"
        Came here to say this. You can also mismatch axle sets to change handling.

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          #5
          You don't need to cut fenders to run 235s. and probably, that's too much tire for an M52 anyway.
          Build thread

          Bimmerlabs

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            #6
            absolutely increase that rear spring to something 12K. Would contemplate more, but 14k (~800lb/in) is a bit much for that front spring.

            Quality 225s will make a big difference as well, but bang-for-buck, I'd do springs first.
            Originally posted by priapism
            My girl don't know shit, but she bakes a mean cupcake.
            Originally posted by shameson
            Usually it's best not to know how much money you have into your e30

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              #7
              My 318IS I run square 245's with a 8k Front/14k rear and a 22mm front sway bar (stock rear) and find the car just on the edge of tail happy. Right where myself (and everyone who drove it the last track day) think it's perfect. -3.5ish front camber, no rear camber adjustment so whatever it ends up at with stock bushings. The car has a very nice controllable amount of oversteer.

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                #8
                Tire pressures have an effect too. Lower pressures in the rear for less tail happy.

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                  #9
                  Thanks everyone for the responses.

                  I know 235's might fit, but one of my rear fenders is filled with bondo. Can't roll it and Im rubbing a decent amount with the 225s. Hence the over fenders.

                  Ill be sliding it around this winter season, so it will be a while until I time attack and test these theories on my shitty turd of a car.

                  I suppose Northern is right in that springs are a good first place to start.

                  Ill left you fellas know.

                  Cheers!





                  Comment


                    #10
                    No, springs are a bad place to start. Start with tires, then move on from there.

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                      #11
                      I have a better place to start: Have the rear subframe bushings ever been changed? If these are original, the rear will be all over the place. Change these first.

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                        #12
                        Originally posted by e30davie View Post
                        "Cheap Hankook 225x17 tires"

                        In the words of Adam Savage - "Well there's your problem"
                        17" BFG Rival S tires with 30 lbs of air pressure in the fronts, 28 lbs in the rears. Or get the 15" wheels so your not rubbing because the Apex 17's kept rubbing at the track on our e30.

                        Good luck!

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                          #13
                          Wow surprised by all the spring rate feedback. I've been sitting on 8k front 10k rear for a while now.

                          Tires and alignment (plus worn bushings) definitely the place to start. What is your rear differential situation?
                          '89 325i OBD2 S52 BUILD THREAD
                          Shadetree30

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                            #14
                            what is this k you speak of? Degrees Kelvin?

                            Last I recall, and it's been a while, I might be 800lbs/in front, 700 rear. It is entirely possible that I've transposed those numbers...
                            ...but the car will lap acceptably with the same rate front/rear (and yes, that means a rear wheel rate about 62% of front wheel rate)

                            Other things that will affect balance, in addition to the above tire discussion:
                            for a track car, you want MORE rear camber. With a 50 series radial R1R, the paddock seems to average about -4 in back.
                            Some of the fastest have more- and some of their strongest competition have less. Most of the rest of us vary it a bit
                            to get even (ish) loaded tire temps.

                            Don't overlook rake- getting the nose down and the ass up has counterintuitive effects on balance- yes, it's quicker to turn
                            in, but grip seems to improve in back, despite what one might think. If it's too waggly right on turn in and not unstable in mid-
                            corner, take some rake out and see what happens. The roll centers on E30s are.... a fiasco, quite frankly.

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

                            Comment


                              #15
                              Originally posted by TobyB View Post
                              what is this k you speak of? Degrees Kelvin?
                              LBS(pounds) / inch vs KG(Kilograms) / mm
                              sigpic

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