Ground Control Advance Design Double Adjustable Shock Installation


I started this project with the casual attitude of "I'm going to swap the shocks and see if that helps me go faster". Well... I succeeded in swapping the shocks. I only hope it doesn't take as much work to go faster!!!

I ordered the shocks in mid January 2002 from Ground Control, with the understanding that they would take about 3 weeks to build. It ended up taking about 6 weeks to get the parts in hand, which, to me, wasn't bad considering they were built to order and I just wanted them in the car by April 1st. Tony, at GC, asked questions about my car and current setup. I've been running the softest suspension around and had pretty good success with it, but I was ready for a change and I had found evidence of coil bind on the rear. ( I was running 150# and 200# springs in the front and 225# in the rear) I knew Vic Sias (BSP Natl. Champ) was running Advance Design shocks and 400 pound springs all around. Tony recommended the same setup on my car, saying "all the fast guys are running them". I thought I WAS a fast guy! What the hell, I took the plunge.

I recieved the shocks around the first of March and began the process of checking the fit of everything, before I completely tore the car apart and began trying to shove it in. I had a local race in mid March that I wanted to make and I knew I couldn't complete the job before then, so I was just looking it over to begin with. I knew the upper strut mounts would not be compatible. The AD shocks had a 5/8" thread while my Tokicos were 14mm (9/16") I was going to build new upper mounts to replace the stock rear rubbery mount and the custom front solid mount(spherical bearings..) I had ordered 5/8" speherical bearings which ended up being on backorder (That was the main reason I knew I couldn't complete the job quickly).



A side by side comparison of the
old Rear Tokicos with the new Advance Designs


The new shocks were considerably shorter than the old rear Tokicos, which were already considerably shorter than the OEM shocks. So I knew I was going to need spacers. GC included a piece of steel tubing just for that reason. The tubing probably would have worked okay, but I was not real pleased with the fit of that tubing so I decided I was going to machine my own out of stainless (mainly because I could). Next I checked the length of the fronts. They were pretty close to the the same length as the old Tokico fronts so I probably could have gotten away with the same mini spacer I had been using. Almost as an afterthought, I decided to drop the front shock in the strut tube and make sure I wasn't missing anything. THEY DON'T FIT!!! When Tony asked the year model of my car, I didn't understand that to mean "What year car did your strut tubes come out of?". Let me put this in bold for anyone skimming this page... ADVANCE DESIGN STRUTS DO NOT FIT IN 240 OR EARLY 260 STRUT HOUSINGS WITHOUT DIFFICULT MODIFICATIONS TO THE STRUT TUBES OR SHOCKS There... now that I have everyone's attention... The outside diameter of the shock is about .025 larger than the ID of the strut tube. No hammer in the world can make that work. If you REALLY want to make it work, you could find someone with a LARGE lathe and bore out the ID of the strut tube a little OR if you are feeling especially brave (or stupid in my estimation) you could turn down the shock body a little. The easy solution is just to go find 280 uprights and use them. I already had late 260 rear uprights so I only had to swap out the fronts which is a relatively simple job.



Since I was cutting down "new" front strut tubes to fit, the valve on the bottom of the shock presented a small problem. Rather than make a spacer to keep the valve from bottoming out, I drilled a 1/2" hole in the bottom of the tube.


The rear tubes were considerably longer than the struts, so I absolutely needed a spacer. This meant clearing the bottom valve was not a problem. As mentioned above, GC included a length of tubing to make spacers from (shown above left, in the middle). It would have to have the ID filed out a bit to fit the shocks. I told GC that I had access to a machine shop and that making spacers was not a problem for me. If you do not have that capability, be sure you both understand what you will need. The photo on the right shows the shock fitted in the spacer.



Once I had the correct uprights, I encountered another obstacle... All Strut Tube Caps are NOT created equal The photo on the left show the top and bottom sides of the two types of caps I encountered. The hex head cap on the left side with the thicker walls fits the top of the strut beautifully. The round top cap on right barely catches the top shoulder of the shock and can allow misalignment. If you are VERY careful with the assembly it can work, but I didn't like it. So... because I could and because it was easier than trying to find more of the hex head caps, I machined an adaptor, as shown in the right two photos


Once I had the struts and tubes all assembled I moved on to the top end of the shocks. When I finally recieved the spherical bearings I was able to complete the upper mounts. Most people with any sense would just buy camber plates and be done with it. Since I was on my own here I had to fabricate the interface between the shock, sping and upper mount and make sure it didn't all bind up. The struts came with the two nuts and a small sleeve. There was nothing to keep the upper spring perch from seating/binding against the upper mount. Back to the machine shop again... This time I made some small cone washers to replace the small sleeve. I had previously made them for the fronts so I only had to take care of the rears this time around.


Here is the hardware that came with the shock, a big nut, a little nut, and a little sleeve. I never figured out what the sleeve was for...


Here are the Cone Washers I made for the rear. Notice the step on the inside. This was needed to allow room for the large nut to fit.


This shows how the cone washer fits with the upper spring perch. The step inside the washer leaves room for the spherical bearing, and two nuts.


These are the front upper mounts I fabricated


You can see the cone washers tucked up under the mount.


Two front uprights ready for installation.


These are the rear upper mounts. the spherical bearing is pressed into the top half and the bottom has a slip fit


Out with the old and in with the new.


Here is a closeup of the rear upper assembly.


Ready to go back together!


This is the suspension at full droop when I first put it back together. The control arm angle is close to what I wanted with the weight of the car resting on it. The shocks only have 5 1/2" of travel. With 400 lb springs I was only going to have the shock compressed 1 1/2".


I went back to the shop and made a 1/2" spacer, which improved things, but I ended up spacing the top mount a full inch to get the shock near the middle of its travel. I don't know how other camber plates would allow you to compensate for this. If you havn't already shortened your strut tubes you can leave them a little longer and put a taller spacer under the strut.


Now that I finally had it all back together, I just need to align it and go try it! Here are a few photos of my alignment setup. Since I don't have any bumpers, I mounted some plastic blocks and conduit in their place. Using that, I am able to run a string down each side to measure the toe angle. It's the same thing as using jackstands and string, but since it is mounted to the car, I can roll the car back and forth to settle the suspension and not affect the setup.



At this time, I only have one event on the new suspension. That being the Houston National Tour. I finished 5th out of 9. F Prepared in Texas has gotten a lot tougher. We had the 2nd, 3rd, 4th, 6th, 8th 9th and 11th place finishers from Nationals running in this event . The other two competitors didn't run in the class last year but would have been in the top 10. I don't blame the shocks for my mediocre performance. The comments I got from friends at the event said the car looked like it was working very well. I am sure I will be in better shape once I get the car and the driver dialed in a little better. The old rear Tokicos were completely blown. I could compress them with my hands and when I would release them they would spring back about 2 inches before they began to dampen anything. The Advance Designs are valved for the 400 lb springs and are STIFF. I had to put almost my full body weight onto them to begin compressing them. Trying these springs with new Tokicos would have been a joke.
UPDATE 8/12/03 - Okay... I have the better part of 2 seasons on this suspension, and I'm not changing anything! The shocks are amazingly adjustable! Far more responsive to adjustment than the old Tokicos. I started on the stiff end of the of the adjustment range and found the car pushing way to much. I softened the front about to about 2 turns to the point where I couldn't keep th rear behind me. Next I softened the rear about a half turn and I hit the balance! The car is neutral through the sweepers, pivots great under braking and drifts just right through the slaloms. I've also hit some bumps that literally have put me airborn. The suspension eats it up without bottoming or binding. I still haven't run this setup at Nationals, to quantify if the car is better (previous best of 4th place, can I get 3rd or better?), but I have done very well on good grip surfaces in Texas. Finshing 4th and 6th overall on the PAX index at Divisional events with approximately a dozen current or former National Champions in attendance. The other FP guys were just hating life at those events. That's a pretty good barometer. This setup seems to work!


In the end I think I fabricated somewhere around 26 parts to put this suspension together the way I wanted. If I had just bought all of the parts, I probably would have spent close to $3000 rather than the $1800 I did spend. This is not a quick job you should expect to knock out in a few hours. Take your time and be sure to put it together right.