Ground Control Coilovers

[John Coffey]

And more exceptions... Glad I said I think. See what thinking gets you... :-)

[conedodger]

If you can manage to get Jay Morris on the phone when you call Ground Control he is a wealth of information on the Z. When he first started having success with the company he was racing a Z. He did the did the corner balance and alignment on my old Z before changing the company to manufacture and sales only and moving up the hill from me in the Diamond Springs area...

[Diseazd]

Diagrams to illustrate different terms...... http://www.ground-control-store.com/products/category.php/CA=97

[preith]

Has anyone else had this problem on the rear struts?

I can emphatically say no. I've recently sectioned a set of 240 struts for Katman's somewhat infamous re-valved Bilsteins and DID section the rears. One race under my belt on them so far (@ Autobahn CC if it matters), the car the most stable it's ever been, with lap times a good second faster. Maybe I'm able to get away with it because the rear squats considerably under acceleration with the GT2-ish motor. The rear ride height is actually about 1/2" higher than the front too. Current spring rates are 325fr/275rr, bars are 1.125fr/.875rr. I'd imagine the bar diameter would affect this too.

I kinda-sorta followed GC's instructions, sectioning the rears to the same overall length as the previously used Tokico's (forget the p/n, their "front" S30 replacement). Because of the stepped design on the Bilsteins I was forced to use a 1/2" spacer up top for camber plate bearing articulation, thereby making the overall piston length close to the old Tokicos.

I actually sectioned the fronts as much as possible, the end result about 1" shorter than the Tokico MR2 struts prior, NO spacer.

New coil over sleeves were purchased from GC well. My biggest complaint was their high tolerance, about .060 larger than the struts. Thinking they sold me the wrong ones I called Jay and to my amazement he said "no, that's how they're supposed to be", and went on to ramble about how grinding down a weld will thin the area around it, but in my case the area was chamfered prior and TIG'd. My solution was wrapping the struts with 22ga sheetmetal, tightening with hose clamps and tacking welding.

I completely agree about mounting the camber plates on the underside, a big pet peeve of mine, I can't fathom why anyone would put them on top.

Edited July 6, 2009 by preith
faded memory

[jmortensen]

I can emphatically say no. I've recently sectioned a set of 240 struts for Katman's somewhat infamous re-valved Bilsteins and DID section the rears. One race under my belt on them so far (@ Autobahn CC if it matters), the car the most stable it's ever been, with lap times a good second faster. Maybe I'm able to get away with it because the rear squats considerably under acceleration with the GT2-ish motor. The rear ride height is actually about 1/2" higher than the front too. Current spring rates are 325fr/275rr, bars are 1.125fr/.875rr. I'd imagine the bar diameter would affect this too.

Did you section the rears to fit the Bilsteins, or did you section them in the front to fit the struts and use a spacer in the rear? I don't see why it would be appropriate NOT to use a spacer. Without a spacer the suspension will be in really different strut positions front and back. Maybe if you're only using a narrow range of the available travel that doesn't matter so much, but I still think you would want to use a spacer in the rear, because there comes a point with the right setup you could literally hit the body on the ground before you hit the bump stop. I haven't actually measured it and it would depend on tire height too, but a Bilstein in the rear with the strut sectioned to fit would be really close I think...

[preith]

Did you section the rears to fit the Bilsteins, or did you section them in the front to fit the struts and use a spacer in the rear?

I sectioned the front to fit the struts and used a spacer in the rears. I don't have my notes in front of me but wanna say about 3 inches. Essentially the difference between the Tockico's and Bilstein's body. In other words the overall length of the strut tube (from gland nut to hub) remained the same as before.

[jmortensen]

I think the original point was that the rear in particular could top out and cause a loose condition, and that happens when you section the rear to fit the strut insert. If you used a spacer in back, you wouldn't be likely to have that problem.

For the record, 2" spacer in back on a 240 housing, 3" on a 280 housing in order to keep the housing lengths the same and still take your section out.

I sectioned the front to fit the struts and used a spacer in the rears. I don't have my notes in front of me but wanna say about 3 inches. Essentially the difference between the Tockico's and Bilstein's body. In other words the overall length of the strut tube (from gland nut to hub) remained the same as before.

I think you mean "changed by the same amount front and rear".

Edited July 6, 2009 by jmortensen

[preith]

I think you mean "changed by the same amount front and rear".

It's a bit confusing but no, I meant remained. They were changed/shortened from OEM back when I installed the Tokicos and in my case "remained" the same when converting to the Bilsteins.

I think the original point was that the rear in particular could top out and cause a loose condition, and that happens when you section the rear to fit the strut insert. If you used a spacer in back, you wouldn't be likely to have that problem.

I suppose we need Coop to clarify. I interpreted his post as the rears were sectioned (w/spacers), only too much for the AD's travel. IIRC, GC's instructions were originally written for the Tokico's - using the front S30's as mine were. I feel safe saying he had to use a spacer as well.

[jmortensen]

It's a bit confusing but no, I meant remained. They were changed/shortened from OEM back when I installed the Tokicos and in my case "remained" the same when converting to the Bilsteins.

Got it now. Thanks. Curious about these spacers. Were these the ones GC provided you with, or did you do something on your own. Mine fit with the parts that GC supplied (I told them I was installing Bilsteins).

I suppose we need Coop to clarify. I interpreted his post as the rears were sectioned (w/spacers), only too much for the AD's travel. IIRC, GC's instructions were originally written for the Tokico's - using the front S30's as mine were. I feel safe saying he had to use a spacer as well.

Yep. If he could clarify that would make the issue easier to resolve. If he had to add a spacer in to fix the condition that seems like a pretty clear indicator he was topping out the struts, which makes me think he sectioned the struts too far.

Edited July 6, 2009 by jmortensen

[preith]

Got it now. Thanks. Curious about these spacers. Were these the ones GC provided you with, or did you do something on your own. Mine fit with the parts that GC supplied (I told them I was installing Bilsteins).

The internal-strut-housing spacers were fab'd using rigid plumbing pipe from the local Home Depot.

The 1/2" tall spacers at camber plate area I made by cutting the tops off the old tokicos and drilling the abandoned adjuster hole larger. Sounds ghetto but it worked pretty good. I was worried the struts would be hardened steel but they drilled very easily. I already owned the GC camber plates and made no mention of the Bilsteins when ordering the coil overs. BTW, I have an older set camber plates, p/n CPZ.

[jmortensen]

Sounds like that must have been fun to figure out. If anyone else has Bilsteins, just tell GC and they machine out the inside of the spring hat to allow room for the larger Bilstein strut for you and provide you with spacers to fit the strut shaft and the 5/8" monoball.

[coop]

Yes indeed I shortened the rear struts 1" too much. The rear end became too twitchy as the inside rear wheel was raising off the ground at times since the strut could not extend far enough before reaching its full travel. See the attached photo for my solution. Note the 1" thick camber plate. Less than ideal but effective.

Please go easy on my welding.