I have a few pictures of the Ground Control AD coil-overs I just received and I thought I would share. Before anyone asks, the car is in the middle of the build and I probably won’t have any driving opinions of them for a while, and even then I have hardly driven stock RX7’s so I wouldn’t be able to compare (sorry)… They are double adjustable mono-tubes, spherical bearings (pillow ball) top and bottom on the front and top on the back (since the bottom merely bolts to the control arm). The rear springs seem (I haven’t measured) to be slight larger diameter than the fronts (probably 2.5” rear and 2.25” front), this is fine with me although I am curious as to why they did it that way. Build quality seems top notch, although I won’t know that for sure until I get a few laps on them. Anyway, enjoy if you like this sort of thing!
Dan

 

Looks good. It is nice that they come with fresh bump stops. Bump stops are important, and I don't recall seeing them on many other coil-overs (though maybe it is just that they are black on other units or something ).

-Max

 

Price? Spring rates?

 

Those look like the springs seen on this page: http://www.negative-camber.org/crisp...c/fcpart29.htm

 

You'll need to find some 4x4 shock boots to keep trash from making it past the piston seal. My AD's had to be rebuilt after 18,000 miles of street driving. When I get home next week, I'll post up the part nos. for shock boots from Summit that work.

I didn't know they offered pillow ball mounts. Mine have rubber bushings that wear out pretty fast. I'll be calling to check on those soon.

As for the spring diameter, mine are 2-1/2 in. F&R. Standard Eibach ERS springs. I started with 550/450 F/R and moved to 450/375 F/R, it puts the power down much better with the softer rear. I wouldn't mind going a little softer, like 350 or 325 on the rear. Can't go any softer on the front or my 255/35/18's would be rubbing.

Jack

 

They were $2,210 to my door. I called ground control and they say the rears are listed as 2.5” ID springs, although they are obviously of a greater OD. The front springs are also 2.5” ID (as the serial printed on them states). I chose to go with 650 lb/in fronts and 550 lb/in rears, which gives me a good range of adjustability in terms of spring rates. I plan on running 285’s on all fours, which is why I chose higher rates, and after playing with front and rear sway bars I will adjust the rates to suite.

As for the dust boots, that is a good idea although this isn’t a street car and probably wont see more than 10k before I want to rebuild them to adjust for new spring rates anyway. On the other hand, better safe than sorry! I would greatly appreciate the links.

When I first called they said they didn’t use spherical bearings, but they do now apparently. The difference in performance is probably very little, but I would imagine that the lifetime would be better in a track car.
Dan

 

Looking good. I picked up a rebuilt set a few months back that came with 10 springs! So if you decide to go with some different spring rates, let me know..

 

AFAIK, the mounts are just GC units. How does that upper bushing wear out, mine's been on there for years? All it does is locate the upper shock shaft.



[QUOTE=Trout2I didn't know they offered pillow ball mounts. Mine have rubber bushings that wear out pretty fast. I'll be calling to check on those soon.
[/QUOTE]

 

[QUOTE=ptrhahn]AFAIK, the mounts are just GC units. How does that upper bushing wear out, mine's been on there for years? All it does is locate the upper shock shaft.



The mounts consists of a lower washer, lower rubber bushing, mounting plate, upper rubber bushing, upper washer, small spacer, then two nuts. That small spacer has a smaller diameter than the hole in the mounting plate so the spacer wore into the top washer until the shock's shaft could move around and wear away at the rubber. I have pictures that better show what happen but don't know how to resize the pics for posting.

Jack

 

Open the picture in paint, hit ctl+W, there you can resize the image by %. If ctl+W doesn't work, click on "image" (three to the right of "file"), then on strech/skew... and thats the same window. To chose the amount you need to reduce the image just devide the maximum file size by the current file size and thats your %.
Dan

 

I cant wait to get mine!

Dan how much does your FD way?

 

Dunno yet, doesn't have the roll cage in it yet (or an exhaust, or a drive shaft, or a suspension yet, or a host of other things... Damn not having enough time to work on the project!!)
Dan

 

Here are the pics of what happened to the front shock mounts. I will be contacting GC to see about ordering pillow ball mounts, hopefully they'll sell the bearing and let me modify my mounts versus buying four whole mounts.

 

That looks pretty nasty...

 

I had some coilovers from GC and they did that too. I don't think they use quality aluminum.

 

that doesn't make me feel so good to know.

 

It happens slowly so you can watch the top washer from under the hood and see if it's getting distorted. Unfortunately. I wasn't watching closely until I could feel the shock move through the steering wheel.

I spoke with Jay at GC yesterday, he said they will warranty the bushings if they wear out (which was my experience a few years ago). There are actually black urethane bushings. He was surprised mine wore out and asked me to send pictures that show the problem I described with the spacer eating into the top washer.

On another note, the reason I called GC was to ask about the pillow ball mounts. Jay came to the phone to say they strong recommend against them on a street driven car due to noise. He said all pillow ball mounts make noise (this hasn't been my experience, though).

For those wanting to upgrade to the pillow *****, they use a different top plate so you can't modify your existing mounts to hold the spherical bearing. Cost for each is $60 for mount with pillow ball and $37 for just the spherical brg.

Jack