The Bouncy Bits
Front Suspension: The front suspension has the longer Maximum Motorsports control arms, coil-over kit, and manual brake conversion, yellow Koni struts for the '04 Mustang, '04 Cobra brakes and spindles, and Earl's braided stainless steel brake lines. The MM brake conversion allows for more room under the hood, saves a little weight, and maybe makes the brake conversion easier. Net weight difference, including control arms, brakes, tie rods, and manual brake conversion: ~ -11 lb.
Comparing the old rotor next to the new on the left, on the right is the old rotor on top of the new. FYI: bigger brakes work by increasing the moment and ability to dissipate heat. What's not hidden by the old rotors is pretty close to the pad contact area on the larger rotors. In other words, it's a matter of leverage, not contact patch area.
The original rack and pinion was leaking, so in goes a stock replacement with '94 Mustang inner and outer tie rods to compensate for the new distance between the old and new spindles. The MM control arms are now mounted approximately .75" inboard as compared to the stock location. Note: Fox platform vehicles' handling can be improved by moving the front control arm pivot point up and inward.
To see how the wheels fit check the exterior shots. With the arms moved inboard, the offset still pushes the tires out too much. Time for more wheels.
Originally, I hoped to have one size and offset wheel at each corner of the car. That's pretty hard to do when changing everything. I found a set of wheels that were the same size as the first set, except for having a different offset. Unfortunately, they were also a different color. Here they are, fresh from getting a matching coat of paint. The one with the blue rim is from the first set.
Rear Suspension: The '04 Cobra IRS is a bolt-in, sort of. Various bits and pieces interfere, depending on where and how it's mounted. If mounted using the factory front mounting points, the upper control arms and upper frame mounts interfere at three different points. A local speed shop extended the forward subframe arms .75" to compensate for the difference between the Mustang and T-Bird suspensions. When the subframe is moved rearward, there are clearance issues on the right side because the forward gas tank mounts are not symmetrical.
My pain is your gain. If you decide to upgrade with new or used parts, make sure you get the all the necessary connecting hardware from the donor vehicle. Caliper-to-spindle bolts are expensive, banjo bolts are really expensive, parking brake cables ... you don't want to ask.
Passenger side forward gas tank mount, before and after: The rear of the upper control arm needs to be where this mount is. The left pic shows one cut before being bent. That first cut wasn't nearly close enough to the tank strap bolt flange (about an inch rearward). On the right is the mount after being cut, cut again, and moved to clear the subframe UCA mount (visible in the right half of the right pic). The most important tool for this part is a BFH.
Mods to the stock IRS: "Stretched" forward IRS subframe arms, Torsen T2R, MM adjustable tie rod ends and end links, MM bushings for the control arms and subframe, MM coil-overs, deleted damper. Including subframe connectors, net weight change from the solid 7.5" rear: ~ 122 lb.
Here's the jig used to mod the subframe and a close-up of the change.
My pain is your gain. If you have an IRS equipped car and decide upgrade using aftermarket bushings, let a machine shop save you some grief by performing the removal instead of you diddling with it. You might need to clean up the outside edges of the control arms after the machine shop finishes. Reassemble from bottom to top: LCA, half-shaft, tie rod, a/s bar, UCA.
Upgrade Prep: The factory deforms the mounting tabs so they "pinch" the control arm bushings into place. The MM bushings include instructions on how to use a combination of nuts, bolts, washers and spacers to straighten the tabs distorted by the original installation and properly locate the control arms. Where the MM tools are really useful is if the tabs that need to be straightened also need to be pushed outwards. Run a long bolt through one tab with a washer on outside, thread spacers-washers-nut-nut-washers-spacers between the tabs, then the bolt through the second tab and finally a washer and nut. Use a couple or three wrenches to thread the two middle nuts away from each other. Make sure the threads and faces of the hardware are lubed. You don't want any binding.
The IRS installed: T-bird springs don't fit the LCA perch. Cobra springs are about 2" shorter and judging from the results, the Cobra lower LCA points are lower than the T-bird's. The left spring actually fell out when mounting the tires, oops.
Before and after shock adapters:
On the left, the new tail end of the old driveshaft. According to the driveshaft shop, Ford only has two pieces for the 7.5" and 8.8", so you either have the right piece or you don't. (I lost the coin toss.) This driveshaft is temporary. A lighter, modified FMS Aluminum driveshaft is waiting to be installed. On the right is a comparison of the hellalame stock (l) and replacement (r) rear anti-sway bar end links.
Modified factory Bilstein shocks. Note in the left image the groove necessary to support the coil-over assembly. On the right, a fully dressed shock.
MM recommends using Konis up front and the factory Bilsteins out back. The only problem is the Mustang Bilsteins are 4" shorter than the T-bird shocks, and when mounted by themselves, provide about 1" of travel. I called Bilstein to see if they make something that will fit, basically a Cobra shock that's four inches longer. I was hoping someone at Bilstein could cross-index their line of fabulous products and come up with a part number. Instead I got this helpful bit of information from the guy at Bilstein, "We don't do bastardized versions, maybe you should try a Monroe or Gabriel." That's very nice of them to be so helpful, but leaves me hanging with an unsolved problem. After a couple of tries, I worked out a mounting solution, CNC'd from 6061 Al.
The adapters, Plan "B" (the zig-zag shape) and Plan "C" (the square shape at the top):
Hopefully this will solve the problem and preclude a "Plan D". Just in case it works, I had two extra pieces made.
Plan "C" installed.
All of these pictures show the car before the alignment and ride height adjustments to the coil-overs.
Rear Brake Lines: Brake proportioning valve including the fittings I guessed that would be needed, a tee on the left side (out) and a 90* on the right side (in). On the right, the prop valve installed for the second time. I used the tab where the factory lines meet as a mounting point. Clearance wasn't testable until after everything was installed.
Because it looked like the LCA would interfere, my first plan is described in the following picture, showing the passenger side upper control arm mount. The mounting hole below the UCA points is where the brake line originally mounted. The pic says the fuel lines are "moved", I haven't done that yet. They will probably be safer there. The prop. valve is currently mounted to the tab where the brake line originally mounted.
If you decide to do this swap, it will be easier to route the brake lines with the cradle out of the car. The best luck I had with test fitting was by bolting the cradle into the torque box and putting a jack under the cradle behind the diff to raise and lower the assembly. Once the cradle is dressed and mounted, there's very little room to maneuver, not to mention being really good exercise for those upper torso muscles.
My pain is your gain. Use teflon tape on pipe fittings. Do not use teflon tape on flare fittings. When bending a flared line, verify the last .5" (approximately) hasn't bent and is straight. Follow these simple suggestions to save money on brake fluid.
A washer about the size of a quarter, notched and split. The notches allow the center cable to seat against the end of primary parking brake cable. On the right is a shot of the relocated primary cable, looking towards the rear of the car. The mounting point is on the inside corner of the driver's footwell, and the cable passes over the transmission crossmember.
After getting the suspension aligned, the car still didn't roll properly. It seemed like the rear calipers weren't releasing. Playing with the parking brake release didn't fix it. Playing with the prop valve didn't fix it. New calipers didn't fix it. Turns out the manual brake kit doesn't fit very well. Fully adjusted to the retracted position, the pedal assembly is still actuating the brakes. One thing's for sure, stopping the car isn't going to be an issue. These brakes work very, very well. The motor overheaded in less than three blocks fighting the brakes.
Final suspension work:
Subframe connectors and subframe cross-braces installed. Welded torque boxes, rear IRS cradle pads welded to the subframe.