As I did with my initial "roll center correction" mod, which landed me with "tall ball joints" and customized lower control arms to mount them... I've gone back to the circle track catalog looking for solutions.
I need MORE roll center correction. Well, "need" is a strong word. But, now that I've felt the benefits of it, now that I've lowered the car some more... I would like to bring the roll center back up to improve the feel of things. And, well, okay sure... "just because".
I can't fit a taller ball joint than what I already have without fitting larger diameter wheels, which I don't really want at this point. (I've also learned that I am tire diameter limited... I can't really go any larger on my tire OD without having rubbing issues) That means I have to work the other end. I need to move the inner control arm mounting points up.
I looked at things and took some reference photos:
Right Side Control Arm, Aft Mounting Point
Right Side Control Arm, Fwd Mounting Point
Distance from the front point to the ball joint is about 15", distance from the rear point is about 18". There is plenty of clearance to the axle, but only about an inch of clearance to the steering tie-rod. The tie-rod and the LCA will move up and down in synch, though. So if there is static clearance there, it's not going to change.
Also, I noticed for the first time that the steering rack is mounted to the top side of the subframe. I thought it was mounted to the firewall, like the Festiva was. Nope. See the bolt head that goes straight down into the subframe? That's the rack bolt. I could easily put a spacer under the rack, fit a longer bolt, and get some easy bump steer correction. The unknown there is how much "slack" there is between the steering shaft from the cabin to the rack. I don't know if trying to shim the rack would cause that to bind. Might have to take it apart and see what it all feels like. Even just a 1/4" shim there would make a difference.
So, the fun part:
Those are standard roundy-round racer parts. Upper control arms for "stock cars", which generally means race cars based on 3000-3500 pound 70's era V8 sedans. Same place I sourced my "custom" ball joint from. If it's strong enough to be an upper control arm for one of those big heavy cars on a dirt track, it's more than adequate for a lower control arm on a 1900 pound Mirage.
The rods are available in any length, so I can replicate the dimensions of the stock control arm. (or whatever dimensions I want) And they should bolt right up to the stock mounting points on the subframe. Might need some custom spacers to get the bolts to fit right, but I know a guy with a lathe.
Where's the benefit in that? Well, aside from infinite adjustability (More caster? More camber? No problem!), using the heim joint ends in place of the stock bushings would allow me to move those ends UP by about a half inch by just putting spacers under the bottom to force them up. I could even get crazy and use a longer bolt with full length spacer in the place where the control arm normally goes... and bolt them ABOVE the subframe to get more like 1-1.5".
All without requiring any CUSTOM work at all. Just readily available common circle track parts. Cheap ones, at that!
Almost looks too easy. Might have to get under the car and take some more detailed measurements...
The downside here would be that heim joints don't have any rubber in them, so it could (will) ride a little harsher than stock. But, the flip side... steering sharpness should improve greatly. And I'd have 4 more spherical joints to keep lubricated. (I already have to lube the tie rod ends and the pillow ball upper strut mounts every month, so not a huge deal)