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  • Suspension Suggestions. GC Coilovers.

    Hello, this is my first thread on this board so feel free to criticize.....

    I recently bought a '88 M3 that came with a few little goodies. A GC coilover setup was one of them. I am looking to improve the ride quality while on the street w/o sacrificing too much performance while hitting some corners and I don't think I will be tracking this car either.

    The car is running adjustable Konis all around with 500f/800r springs and shortened front strut housings. The front pair of Konis are blown and have been since I bought the car a couple of months back (how common is that?). The swaybars have been upgraded to Ireland Engineering 25mm front and 22mm rear. And every bushing and mount has been upgraded to polyurethane.

    This car loves riding on fast, smooth, and twisty roads. When I drive on slightly bumpy (average) roads at slow speeds the car seems very stiff. So stiff that I can hear every bushing in the car squeak and my head bobs around like a goddam jack-in-the-box.

    Are the spring ratings race, street, or somewhere in-between? Spring Suggestions?

    Am I going to notice a huge improvement in stiffness by simply replacing the front shocks? (I realize this Q might sound stupid)

    Would going back to stock swaybars improve streetability?

    Is anyone running a GC coilover with a comfortable street car setup?

    Does ride height of the adjustable coilover setup effect ride quality?

    Heres a pic.





    I apologize if these questions have already been asked or if i posted in the wrong place.
    Last edited by bMar; 06-24-2010, 07:09 AM.
    sigpicTear along dotted line.

  • #2
    For years GC was for racers only. Then people started running them on the street and they are streetable since you can choose your own spring rates when you order the kit. However, 500/800 is definately on the stiff side which is more of a personal choice. A typical street setup is 350-450 front and 550-650 rear. In addition, those oversized IE bars are the largest bars on the market for the E30. A typical e30 aftermarket sway set is 22 front/16 or 19mm rear. As you can see you have a very stiff setup.

    It's interesting that the front Koni's are blown. Are you sure? Make sure you get the short revalved version from GC. New springs will run you $300 or so if you buy them new. Perhaps you can find someone who will trade springs with you.

    I couldn't help but notice the rear wing on your M3? Looks different.
    Last edited by Reelizmpro; 06-24-2010, 09:02 AM.

    88 M3 - LACHSSILBER/M TECH
    89 M3 - ALPINEWEISS II/SCHWARZ
    85 323I S52 - ALPINEWEISS/SCHWARZ
    91 M TECHNIC TURBO - MACAOBLAU/M TECH


    Comment


    • #3
      +1 on the springs.

      Check the setup of the swaybars and put them on the softest setup, what front swabar links are mounted (swaybar linked to strut or to wishbone)? I would recommend to use the wishbone link.

      What do you mean by "blown" shocks? have they lost their damping? Have you tried changing the damper stiffness (rears must be removed)?

      The car is somewhat in a vicious circle
      heavy lowering --> requires stiff springs
      stiff springs + stiff swaybar --> requires stiff damping
      alltogether --> spoils ride quality

      Have you checked if there is suspension travel left, or are you on the bumpstops already?

      If you only want drive the streets, I suggest raise the height, go for softer springs, try to keep the swaybars as they give quite good bodycontol and adjustability.

      Thomas
      sigpic

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      • #4
        Originally posted by Reelizmpro View Post
        I couldn't help but notice the rear wing on your M3? Looks different.
        Ya thats what some others have said too. Some have said its an Evo II wing, I don't even know if there is such a thing. I don't know the history with it, the wing has what looks like to be a poor patch job at the midspan on top. I am in the market for a new one as I am somewhat of a perfectionist. It looks to be taller than stock too. ???

        Thanks for the spring info.
        sigpicTear along dotted line.

        Comment


        • #5
          Originally posted by TR-Spider View Post
          +1 on the springs.

          Check the setup of the swaybars and put them on the softest setup, what front swabar links are mounted (swaybar linked to strut or to wishbone)? I would recommend to use the wishbone link.

          What do you mean by "blown" shocks? have they lost their damping? Have you tried changing the damper stiffness (rears must be removed)?

          The car is somewhat in a vicious circle
          heavy lowering --> requires stiff springs
          stiff springs + stiff swaybar --> requires stiff damping
          alltogether --> spoils ride quality

          Have you checked if there is suspension travel left, or are you on the bumpstops already?

          If you only want drive the streets, I suggest raise the height, go for softer springs, try to keep the swaybars as they give quite good bodycontol and adjustability.

          Thomas
          The links are attached to the strut on my car.

          By "blown" shocks i mean, thats what my mechanic said. I took a look at them myself too and found oil on them. So, they are leaking.

          I am willing to swap out the springs for new softer ones and obviously get new shocks. If I do this, is it a must that I raise the car? Will this quiet down the squeaking, or is that just a symptom of the polyurethane bushings?

          What about the installing stock swaybars as an option, I have them sitting in my garage?
          sigpicTear along dotted line.

          Comment


          • #6
            Yeah that wing is not OEM. It appears to be thicker and slightly taller. Anyway, softer springs and new shocks would be the first step, then adjust the sways to "soft" since they are slide adjustable. Keep in mind, those IE sways use beefier mounts and bushings. If you go back to stock, you will have holes left over in the rear body. Poly bushings should be lubed with lithium grease every now and then to prevent squeaking. The reason GC uses shorter Koni's is so you can lower the car and still have suspension travel, which is why I'm surprised they are blown with those stiff rates. You don't appear to be THAT low but if you raise the car you will get more travel.

            88 M3 - LACHSSILBER/M TECH
            89 M3 - ALPINEWEISS II/SCHWARZ
            85 323I S52 - ALPINEWEISS/SCHWARZ
            91 M TECHNIC TURBO - MACAOBLAU/M TECH


            Comment


            • #7
              Originally posted by Reelizmpro View Post
              Yeah that wing is not OEM. It appears to be thicker and slightly taller. Anyway, softer springs and new shocks would be the first step, then adjust the sways to "soft" since they are slide adjustable. Keep in mind, those IE sways use beefier mounts and bushings. If you go back to stock, you will have holes left over in the rear body. Poly bushings should be lubed with lithium grease every now and then to prevent squeaking. The reason GC uses shorter Koni's is so you can lower the car and still have suspension travel, which is why I'm surprised they are blown with those stiff rates. You don't appear to be THAT low but if you raise the car you will get more travel.
              I had the car inspected twice, once before purchase and once after by a E30 M3 enthusiast (CG Motorsports) up here in Vancouver. They both said the front Koni's were blown due to oil being all over the shocks. The previous owner insisted it was the oil placed in the strut housing for heat dissipation that must have splashed out. I would think that would only be a temporary problem right after install for a few hundred miles or so, or until the excess oil removes itself.

              I've put on about 3000 miles since Buying it in Feb. and when I went to swap the tires i inspected the shocks and there was a dark yellowish dirty oil on the stainless cylinder part of the shock. I'm assuming that this is the shock oil. Is there any way to test the shock so I could be absolutely sure without removing them from the car? Its hard for me to tell with such stiff springs and no knowledge of what they used to feel like when they were new. I would not have thought they were blown just by driving the car. It feels OK to me, just really stiff....

              Thanks for the tip with the bushings.

              Marty
              sigpicTear along dotted line.

              Comment


              • #8
                Are you coming to the picnic?

                I may be interested in buying your wing if you want to sell it...

                To check in the shocks are blown the easiest way would be to have someone watch your front suspension on a bumpy bit of road. If it bounces around alot it is definately gone. You could try cleaning all the oil off the front struts and watching to see if it returns.

                -Dan

                Comment


                • #9
                  Originally posted by Dirtsquirt View Post
                  Are you coming to the picnic?

                  I may be interested in buying your wing if you want to sell it...

                  To check in the shocks are blown the easiest way would be to have someone watch your front suspension on a bumpy bit of road. If it bounces around alot it is definately gone. You could try cleaning all the oil off the front struts and watching to see if it returns.

                  -Dan
                  I was thinking of headin' down for the picnic.....Still on the fence about it?

                  Driving around on a bumpy road sounds like torture, but a visual might work. Does the ajustment of the shocks fail if the seals go on the shock, or do they control a different, independent part of the shock with the Koni Adjustable shocks? I have cleaned the shocks and the oil came back in a recent test. They must be done, Eh?

                  Mar
                  Last edited by bMar; 06-24-2010, 03:07 PM.
                  sigpicTear along dotted line.

                  Comment


                  • #10
                    Originally posted by bMar View Post
                    I was thinking of headin' down for the picnic.....Still on the fence about it?

                    Driving around on a bumpy road sounds like torture, but a visual might work. Does the ajustment of the shocks fail if the seals go on the shock, or do they control a different, independent part of the shock with the Koni Adjustable shocks? I have cleaned the shocks and the oil came back in a recent test. They must be done, Eh?

                    Mar
                    Adjustment won't fail but if there is no oil in them or they do not hold any pressure then they will jump around.

                    Have you ever noticed another drivers wheel hopping up and down while they are driving on a rough section of road? It's because thier shocks are blown and not controlling the spring.

                    If oil is appearing around the shafts then I would say they are gone. I believe you can save some money and send them back to Koni for a rebuild. A race shop in your local area might have someone who can do that for you as well. Expect a week or more of downtime with that option.

                    -Dan

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                    • #11
                      Sway bars have little effect on ride, mostly during cornering. You have springs that are stiffer than most use racing. I think the springs may have been put on there to compensate for a blown shock. My two cents.

                      Comment


                      • #12
                        Originally posted by bMar View Post
                        Are the spring ratings race, street, or somewhere in-between? Spring Suggestions?
                        Somewhere in between. I run 800/750 on the street and it is not harsh. Most of the harsh feeling in a "sporty" car comes from the shock valving, not the spring rate. A stiff OR a blown shock will radically affect the ride quality, but in different ways. Your car is low. If the GC kit was installed without cutting the strut to use GC's shortened shock, you could be bottoming which will be the worst possible ride you can imagine, PAINFUL.

                        Originally posted by bMar View Post
                        Am I going to notice a huge improvement in stiffness by simply replacing the front shocks? (I realize this Q might sound stupid)
                        Yes, if the current ones are blown and the car is bottoming, the difference with new, properly dialed-in shocks will be drastic.

                        Originally posted by bMar View Post
                        Would going back to stock swaybars improve streetability?
                        YES! The swaybars tie the sides of the suspension together, reacting a bit like a solid axle. Only if you hit a bump of the same height at the same time do they not affect the ride. From personal experience, the IE bars seriously affect the ride, especially on a bumpy road...
                        Originally posted by bMar View Post
                        Is anyone running a GC coilover with a comfortable street car setup?
                        Try yours once you've determined if you're running out of suspension travel. Put a tie-wrap around the shock shaft in the front. Drive on the bumpy roads in question, then check if the tie-wrap has moved up against the bump rubber. Also, IF you don't have travel issues then replace the shocks. At that point, you could consider a spring change. My feeling is that 500 in the front is not very stiff.

                        Originally posted by bMar View Post
                        Does ride height of the adjustable coilover setup effect ride quality?
                        See above (bottoming)
                        Anders

                        "Objects in mirror are losing..."

                        Comment


                        • #13
                          ^^ Thanks for the detailed response. The strut housings were cut down by an inch. I haven't felt anything that feels like I'm bottoming out up front.

                          Would Ground Control warranty the shocks, I may or may not have a reciept? What is a typical warranty on Koni Adjustables?

                          I will probably try replacing the shocks first to see how that affects the ride quality first. If that alone gives me some relief on bumpy city roads I think I will be satisfied. Like I said earlier, the car handles so well on the roads where I am pushing it, and its an absolute thrill to drive. I'm actually amazed at how well the car performs, its driver feedback is better than anything I have ever experienced. I would hate to soften it too much and loose the sensation I have come to appreciate so much.
                          sigpicTear along dotted line.

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                          • #14
                            If you would be interested in a trade let me know.
                            I have a set of h&r race with bilsteins less then 3500 miles on them.

                            @slowprogress

                            Comment


                            • #15
                              My experience with the Koni SA's and Bilstein Sports is that 500 in the front on anything but a fairly smooth road, even with milder sway bars, is bouncy. I have a pretty high tolerance for this stuff on the street having had many different set ups that I've used on the street in many different cars. It never really bothered me much since that's what I was used to but having since used AST's I now find the Koni's to be a bit annoying and bouncy, Bilsteins too. If it was what I had I would certainly put up with it and not really complain but it's hard when I have now experienced something that is so much better in every way.

                              I do openly admit that the roads I typically drive on are pretty bad, worse than probably what most experience. I ran 2 different spring rate set ups on my former street E30 M3 (which had clunking/banging/popping bearing camber/caster plates and RSM's as well as 22/16 sways)....375/500 and 450/600. Neither were really all that pleasant on the street but totally doable. Former absolutely sucked on the track, IMO, and the latter was decent but left something to be desired.

                              Overall there was a compromise one way or another but both were good improvements over Bilstein/H&R and certainly stock.

                              I'd be curious to see if your front dampers are really "blown" or not. If the Koni's are SA's then you should be able to adjust from full stiff to full soft and feel a difference, even if mild. If there is no difference or if they're just completely bouncy with no obvious damping then yeah, probably blown. They may just have leaked some oil which is not desireable and they should be serviced but a fully blown damper provides no damping at all and typically is pretty obvious.

                              Have someone follow you down a road that has some bumps. Have them observe the 4 corners of the car. A blown damper will allow that corner, even with sways, to bounce like crazy, it's very clear. And presumably one or more corners will be much different than the others such that, again, it's very obvious.

                              Cheers.
                              Jack Money
                              '88 M3 #20 DM/GTS2
                              Elephant Motorsports Inc

                              AST Monotube Adjustable Dampers and Coilover Kits - Full Service Stocking Distributor
                              Swift Springs Master Distributor
                              JE Pistons Distributor
                              Schroth Safety Products Distributor
                              Motul Fluids Dealer

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