Coilovers question

[Jb325is]

J-stocks aren't linear springs as far as I know.

The struts do not need to be cut for the Bilstein J-stock dampers. They are the same length as E30 Bilstein Sport strut cartridge.

If you want maximum lowering ability, then you will want to cut the spring perch off so that the spring height adjuster can use the bottom half of the threaded sleeve.

I am running J-stock dampers with 2.5" springs, 550 front, 750 rear, with GC Race plates.

Interesting, looks like they are progressive... Didn't know that

But yeah, I have a friend that has been running a similar setup for years and loves it. I think he's running 650/900 or something for springs

[ed94r]

J-stocks aren't linear springs as far as I know.

The struts do not need to be cut for the Bilstein J-stock dampers. They are the same length as E30 Bilstein Sport strut cartridge.

If you want maximum lowering ability, then you will want to cut the spring perch off so that the spring height adjuster can use the bottom half of the threaded sleeve.

I am running J-stock dampers with 2.5" springs, 550 front, 750 rear, with GC Race plates.

Bingo. Just what I needed to hear, and precisely the rates I wanted to run. Thank You.

Ed

[BlackbirdM3]

I completely understand how the Vorshlag design won't bind on the top of the spring perch since they are 11mm taller than the GC design (whether that is a feature or not is debatable), but I don't see how their design is any different when it comes to the center of the spring perch. In what way do you say the GC design doesn't support the center of the plate, and how is the Vorshlag different?

Full disclosure: I haven't even received my GC plates yet. I have IE plates on the car right now. I chose GC over Vorshlag only because I am trying to lower the front of my car more to get more static camber, and the GC design is the thinnest on the market.

The Vorshlag spring hats are one piece and fit into the camber plates. Its the very center of the hat the fails, right around where the strut seats that fails on the GC parts. This would appear to not be an issue with the Vorshlag ones since the whole center of the hat is supported.



Will

[Digitalwave]

@Blackbird, I think that's apples to oranges. The Vorshlag SpecE30 plate is different because SpecE30 rules require the use of the OEM upper spring perch. These ones you pictured are a nice design though, for those using stock diameter springs but not racing in SpecE30.

[BlackbirdM3]

@Blackbird, I think that's apples to oranges. The Vorshlag SpecE30 plate is different because SpecE30 rules require the use of the OEM upper spring perch. These ones you pictured are a nice design though, for those using stock diameter springs but not racing in SpecE30.

ANY race series should have the sense to run parts that work and work correctly. Otherwise what is the point? I think the Vorshlag ones are stock hats that they modify (I might be wrong.) Either way, the Vorshlag design is far better than the GC design.

Will

[Emre]

Just chiming in because folks have brought up J-Stock.

TMS J-Stock springs are just copies of BMW Gr.N springs. They're the furthest thing from linear. Not only are they progressive, but it hardly takes any compression before you hit the stiffer part of the spring. That's what makes them so bouncy. Unless you're on silky smooth roads, you're basically riding on bump stops.

As for the J-Stock Bilsteins, they're the same as regular Bilstein Sports, but revalved to Firehawk spec and mounted upside-down.

[ed94r]

Just chiming in because folks have brought up J-Stock.

Unless you're on silky smooth roads, you're basically riding on bump stops.

I'm not clear here...are you speaking of a spring rate low enough that it allows compression to the point of the shocks being on the their stops? I would think that with the relatively high spring rate, the opposite would be true...the shocks would never see the stops because of the high spring rate. Or, are you speaking of coil bind, where the spring rate goes to infinity?

I would like to stay off the bump stops.

Thanks, Ed

[vitiokas95]

Not to hijack thread, but I will have my GC set with housings, springs, camber plates etc for sale in few weeks. Pretty much identical what was for sale at Panjo few weeks ago. Waiting for my MCS set to come in and then will be selling mine. PM if someone interested.

[BlackbirdM3]

I'm not clear here...are you speaking of a spring rate low enough that it allows compression to the point of the shocks being on the their stops? I would think that with the relatively high spring rate, the opposite would be true...the shocks would never see the stops because of the high spring rate. Or, are you speaking of coil bind, where the spring rate goes to infinity?

I would like to stay off the bump stops.

Thanks, Ed

The J stock spring rates are 640 front 1080 rear, and I'm never on the bumpstops on my car. I was with the H&R race springs, but never on the J stocks. They also aren't bouncy at all. Coil bind is possible, yet unlikely. I don't see any evidence of it on my springs.

I have seen some of the early J stock springs made by Eibach listed as the same spring rate as the H&R race springs, but the ones I have are much beefier than the race springs that I took off the car when I installed the J-Stocks. If I remember I can get the part numbers off the Bilstein J stock dampers I have. They have far more damping on both rebound and compression than stock Bilstein Sports.

Will

[TobyB]

ANY race series should have the sense to run parts that work and work correctly

Bwa aha hah hah!!!

Thanks, that made my whole morning....

https://www.scca.com/pages/cars-and-rules

t

[Hellabad]

Oh hey.

This is Jay from Ground Control. I have been told of some questions in this thread by someone. (I don't know real names).

I feel bad for not posting on R3V for a long time. I don't want to be "that guy", but sometimes it just happens. ...But just in case you think I haven't been down with the struggle for e30 and e28, I have attached a few pics.





Thanks to everyone here who keeps posting, and lets me see what the valve lash specs are, while I'm helping my kid adjust his valves at 10 at night.

next post clarifies questions about camber plates and springs.

[Hellabad]

https://nasa-assets.s3.amazonaws.com/document/document/4276/SpecE30_2017_V1.0.pdf

Almost all of the posters in this thread are exactly correct about everything, but I just want to c-l-a-r-i-f-y a few things, because some misconceptions have started to appear.

GC (aka Ground Control) makes 6 different CCP (camber/caster plates) for e30. They are ALL on the GC website.

One of the CCP, "GC Spec e30" is made only for racing BMW e30s in a race class called Spec e30, and only to use Bilstein struts P36-0335 with P30-0334 and HR front Springs 50404-88F and EBS-BMW-3/1. There are few if any other racing classes that require ccp and stock diameter springs anymore, so racers choose coilover springs and adjusters for racing.

There are other HR springs and Bilsteins that physically bolt up to GC CCPspec-e30, however the rules require a spring that does NOT coil bind.



Spec e30 spring does not coil bind:



HR race spring does coilbind, and this will bend any stock spring perch it is jammed against. (stock perch is required by Spec-e30 rules)



So, when using springs that can coilbind, GC recommends the GC "CCP-Touring" with a heavy duty (1.7 pounds) spring perch that is very strong because GC is not trying to satisfy a set of racing rules. This plate is steel, very strong, but does have limitations to remain streetable and quiet.



Here is a link to two of the GC camber plates, and their ranges of adjustment:

http://ground-control.com/images/bmw/e30/comp/

GC spec e30, Bilstein and HR spec e30 only, racing only.
GC e30 touring, any strut, stock or coilover spring, urethane bushings and street bearings.
GC e30 Hybrid, track day car, coilover with urethane spring pad, quick adjust.
GC e30 Street Prepared. coilover only, mounts under sheetmetal to satisfy SCCA rules.
GC e30 SCCA Improved Touring, coilover only, cutting required.
GC e30 Rally, coilover only, integrated stress bar, steel construction.

[BraveUlysses]

hey while you're here, what kind of maintenance do my GC hybrid camber plates require? thanks!

[Hellabad]

hey while you're here, what kind of maintenance do my GC hybrid camber plates require? thanks!

once per year, preferably before it rains a lot.

[Revzillia]

If your looking for Koni yellow. Double adjustable. I have a set for sale 575 One front shock is blown but theses are 1200-1400((retail. I bought them in june