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  • Originally posted by kevnj View Post
    I’ve read from internet experts that GC konis cant handle 1000 lb springs and max out around 700.
    GC told me they valve their Konis for a range between 400lb to 900lb.

    Originally posted by kevnj View Post
    Do you think the konis are a better choice then fooling around with the Billys?
    Not sure. From what I gather reading this and other forums, some people prefer the Bilsteins and others prefer the Konis. I believe GC uses strut inserts from the VW Corrado (G60) in their shortened M3 struts. They also use a small length of tubing at the bottom of the strut as a spacer. This piece of tubing is cut to fit in order to properly align the top of the strut with the top of the shock body. But if you have full length struts then it is doubtful you can use a shorter strut.

    Does Spec E30 have ride height minimums? I know PRO3 does (car can't be lower than 5" from pinch weld to ground). Maybe GC configured their Spec E30 setup to not be able to be adjusted lower than the minimum ride height for the class.

    Does your setup look like this? (This is from an e36 but its the same on the E30)

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    1990 M3

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    • Here’s the best pic of have of the struts assemblies with inserts. The camber/caster plates attach to the piston without any type of external bump stop.

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      • Here’s pics of the front passenger corner.

        The strut has maybe a little over 2 inches of travel but when you factor in the internal bump stop it’s less then that.

        There’s close to a 2 inch gap to the fender from the top of the tire. I’ll need to recheck my measurements from the pinch weld. I should be able to go much lower without having the control arms go beyond parallel.

        When I was using the 440’s up front vs the current 700’s the car was over an inch lower. The increase spring rates and dampeners raised the car up over an inch. Makes sense but surprised it made that much of a difference. Car weighs 2412 with me, my gear and a full tank of gas.

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        • Now that I see you have a non-M3 E30 the fender-to-wheel measurements I provided are probably not valid as I have an M3 which as you know has different fenders and cutout profiles. You mentioned "Using full length front strut assemblies with the billy sport inserts" confuses me (easily done) as I know the GC coil over conversion sections the front struts.

          Here is a link to a video showing this done. My apologies if you have seen this. Not sure what Bilstien cartridge the guy is using, however I noticed he is using 6" springs.

          https://www.youtube.com/watch?v=8Q7xUSNRyLI

          Whatever Bilstein cartridge he is using it is shorter than a standard E30 cartridge as he uses a spacer to bring the top of the cartridge in line with the top of the strut housing. This is the same procedure GC uses with the Koni inserts.

          Not sure any of this is helpful to you or not.
          1990 M3

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          • kevnj
            kevnj commented
            Editing a comment
            Oh got it, yeah guess we were having two different conversations. I have seen that video, was watching it last night. I may go with e30 IX inserts, they maybe the ticket as they are shorter.

            Like anything all the tinkering can be fun but when you add up your time and the cost to go through a few iterations it ends up costing substantially more. You do tend to learn something so I guess that has value too.

        • IIRC the iX inserts are 3" shorter. Unfortunately Bilstein only offers the B6 not the B8. Probably a difference in valving which you will be changing anyway.
          1990 M3

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          • Originally posted by kevnj View Post

            Sorry if my posts have annoyed anyone, just an enthusiast trying to learn and share my experiences with the community.
            I apprecieate your posting bud, as another non-M e30 owner intruding on s14.net in order to get some J-stocks in my life. Overall, this forum has been a massive help to my race team and my suspension knowledge.

            I love your orange E30 - the ES front valence + plastic bumpers looks awesome.

            Plus, my E30 is the same color Orange, and also has a 4v swap (m54b25)

            Click image for larger version

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            Regarding the B6 struts - From what I understand from my bilstein contact, they are "taller" due to internal bump stop differences (when comparing RWD B6+B8). If needed, I can try and get more info for the front IX inserts.

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            • Cool enduro car. I own a M3 as well and have built the non-m to be the track toy. In the shadows there's still a bunch of people on S14.net who actively track there cars. There's a WEALTH of knowledge to be shared. I'm going to get the Bilstein dampeners re-valved to proper J-Stock specs once I get dyno plots to ensure there are no more disconnects.

              For the front inserts, I am now leaning towards doing the Koni SA's from GC as they are valved correctly for 700lb springs and allow me to get the ride height where I want it to be. For the rear I will either use the Bilsteins with an extended height rear shock mount or see if I can find something adjustable that can handle the 1K springs in the ~$250 a dampener price range.

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              • Ken -

                If you are going to get the GC front Konis ask them if they can revalve the rears (8041-1289spgc) to work with 1000lb springs and get a set of their rear bump stops. The Konis they use are shorter in overall length which will work with a 5" spring (I have their rear Konis). I wouldn't use an extended RSM.

                If you move from the Bilsteins to the front Koni inserts you'll need a new pair of strut housing caps. Use part number 31 32 1 117 376.
                1990 M3

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                • kevnj
                  kevnj commented
                  Editing a comment
                  Thanks for the info, will report back with the results.

              • Inverted Shorten'd Koni?

                Maybe the substitute for the rear Bilstein.

                I have a set of the Jstock Bilstein fronts from turners recent mystery set, Looking for Inverted rears to match..

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                • Originally posted by Yahweh View Post
                  Inverted Shorten'd Koni?

                  Maybe the substitute for the rear Bilstein.

                  I have a set of the Jstock Bilstein fronts from turners recent mystery set, Looking for Inverted rears to match..
                  No inverted and shortened Koni that I am aware of. IMO the inverted rear shock is overrated for street or light track. Even if you are a serious racer I'd doubt you could tell the difference between an inverted rear and a non-inverted rear. The unsprung weight loss is minimal.

                  Assuming you are using the J-Stock springs, I would get the Bilstein Motorsports rears (24-000642). They are correct for that spring length. The valving is 200/200. The rear J-Stock rear springs are 7" long. If you are using a shorter spring than that just go with the Ground Control Konis. They have a shorter overall length and are intended to be used with a shorter spring.

                  If you must have an inverted rear, find an early set of the Bilstein B46-1720 with an H0 suffix. These shock housings are not crimped. The most current production B46-1720 shocks have a crimped housing and cannot be revalved. See post #308.
                  1990 M3

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                  • Yahweh
                    Yahweh commented
                    Editing a comment
                    Hoping to keep inverted per a nice "period" correct Kit.

                    Small differences add up.

                    E350 with Quigley 4x4 used to run the B46-1720 damper re valved up front until the same issue. Looks like now people run FOX shocks..

                    GC does have an inverted koni, unless you have a P/N... GC wont sell it individually, as described its for their true coil over rear "kit"
                    Maybe the inverted koni is a monotube and would match the front better..

                    The 24-000642 Group N sounds like the only entry level bilstein option, and also not the 200/125 valving. Which optimally makes this a great package.
                    Unfortunately doesn't check the inverted box, which is optional....

                • What about the B46-1720 in b8 from?

                  IE
                  F4-BE5-H341-H0 or 33-187563

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                  • Originally posted by Yahweh View Post
                    What about the B46-1720 in b8 from?
                    Does Bilstein make such a version? Looks like it is a B6 variant. Assuming the length is the same as the B46-1720, the 33-187563 would still need to be revalved, unless it has the crimped housing.

                    Regarding the "period correct" thing, if you look in the BMW Motorsport Gruppe N catalog for the E30 M3 you will find the Bilstein 24-000642 (BMW part number is 33 52 2 222 588) so it is very period correct. Plus your 33-187563 would not be period correct in any event.

                    1990 M3

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