Torque arm/coilover question

[jaybee]

OK, thanks for asking. I'm still looking for the right car, but the intent is to find something in the Falcon/Fairlane/Torino/Maverick family. A Mustang at the right price would work, but those are harder and harder to find, even in a notchback. The vision for the car is to have it drive well by modern standards even when pushed a little. None of this "handle like a new Corvette" nonsense, but I should be able to throw it into a cloverleaf, blow through a roundabout, or work the pedals on a twisty road enough to get my heart rate up without scaring me half to death. Or killing me to death. I had a 1968 Cougar and a 1969 Cougar. LOVED the '69, but I never had any illusions of what it could do. No 700hp, no Coyote swap, no mini tubs, no radical body mods, no bespoke chassis. Engine limited to a 351W or 347 with enough work so there's no question it's warmed up but not so much as to make it a temperamental beast. As much of the work as possible should be in stages. I love the magazine quality builds on the Projects page, but I don't have that kind of money. Besides, there's a secret hidden in that part of the forum, and a lot of others. How many threads start with big plans, get some parts bought, big chunks of the car cutaway, and then they go dead? Cars should be on the road as much as possible, within reason.

About those stages, which of course will vary based on the principle that Job One is to make sure it's safe and reliable. First, Monte Carlo bar and Export Brace, maybe some other details like Boss 302-style belly bar or some of the other shock tower reinforcements that were used on various 1st gen Mustangs. Rollerized spring saddles. Shelby/Arning drop. Sway bars. My preference is for a soft spring/stiff(ish) bar setup. I don't like the movement that can come from the stock strut rod bushings, but I'm also no fan of heim joints or other unsealed, metal on metal joints on the street. That stuff is for race cars, which get checked, cleaned lubed, and replaced constantly. Opentracker has Delrin monoball bushings which look like a good option. They're not metal on metal and the concave washers may do a good job of wiping dirt out of the bits. Dial in a wheel alignment friendly to modern tires, with lots of caster. That just about necessitates power steering, and the most expensive single chassis bit may turn out to be a Borgeson steering box. The Bendix ram-assisted steering and I have a checkered past, and the 16:1 and 19:1 stock steering boxes are very old school.

Most of the chassis I've described can carry a 275-305 width tire on all corners, depending on model, and be very close to stock height overall on a 17" wheel. That's enough room for later model Mustang brakes with decent sized rotors, and for some combos there are even caliper brackets available. Plenty adequate for the usage I have in mind on cars that are 2900-3300 lbs and WAY less money than Wilwood, Baer, or other track-quality systems.

Given all that, why not just stick with leaf springs? Maybe I will, by that time, but with probably 400-425hp and everything else updated, IMO the leaf springs will be the sketchiest part of the car. Options like a triangulated 4 link or a 3 link would require cutting up the car pretty severely. More so than a torque arm, which seems to work well from both a packaging and performance standpoint on a lot of cars. The hard part of the Panhard bar will be building a frame mount which positions the bar low, flat, and long for best motion. The trailing links can be fabbed up ahead of time to bolt up to the front spring mount and the leaf spring saddles. Dead easy stuff.

Coilover mounts aren't so bad, it's just a matter of where to put them, which is where my question came from. Can't just bolt them to stock shock mounts, but it's not rocket science. There's enough stuff back there to share the load into. Frame rails, trunk floor, shock mounts, perhaps even the pinion snubber mount. Maybe put a steel firewall behind the rear seat to help spread the load into the rear torque boxes, package tray, wheel tubs, and up into the C pillars.



That just leaves the torque arm itself. Plenty of ways to build one of those. I like the way the Maximum Motorsports TA for Fox body Mustangs is built, but with spring saddles on the axle tubes to make it stronger. I'm not quite sure what to do about the front mount. The RRS style of crossmember is one possibility. Or maybe something built up into the tunnel so it stiffens that structure, forms a driveshaft loop, and lets the torque arm mount underneath. The front mount still has me concerned. No heim joints, remember? That would apply to unsealed telescoping joints as well. And there's only so much space under there. Maybe a BMW trailing arm link. They're pretty small. A builder I trust told me he's had good luck using a Ford pickup radius arm bushing. It's big, squishy, and designed to make all the same motions a torque arm has to make.

Hope I haven't gone from undersharing to oversharing, but that's the scoop.