Torque arm mount

[enjenjo]

The Loading on the front of the torque arm is not very much. On the F body it was mounted off the rear transmission mount.

[jaybee]

True, it's a very long lever. I'm thinking of its potential for increasing chassis rigidity. When people think of aftermarket pieces to increase chassis rigidity they most commonly think of frame connectors. They do a lot in beam but not much in torsion. One of the things I thought was interesting about the RSS product is that they insist their product doesn't require frame connectors. They change way axle torque is fed into the chassis by reducing its intensity and applying it where the unibody is stronger.

[jaybee]

The more I think about the exchange above, the more I realize the purpose of the RSS crossmember is to be able to say it bolts into a precisely located and identifiable location on the unibody and can be installed without removing the seats and carpet. It's made with low profile tubing, so it can't be all that strong. It doesn't actually have to be. A torque arm length of around 40" presents a greatly reduced vertical load, as Frank made note.

I like this solution, from a 2nd gen Camaro that gets run at track days with a twin turbo sbc, so it gets worked pretty hard. The torque arm mounts to tabs welded to plates which are perimeter welded to the driveshaft tunnel.

[kb426]

I love creativeness.

[enjenjo]

here it is

[jaybee]

I like that. Nice and sturdy, and there's no real reason it has to be symmetrical or mount to both sides. The important dimension is where the front mount sits relative to the centerline of the car. Even that probably isn't a huge deal unless you're building a track day or autocross car.

[enjenjo]

If you use a compliant mount at the front it doesn't need to be the same length as the driveshaft as long as you have some other means of locating the rear axle. Think of it as a very large MOPAR pinion snubber. I used a 85 Ford F150 rear cab mount bushing on the ones I did.

[jaybee]

That bushing sounds ideal. The side that goes between the cab and the frame is very tall and the process is to torque it down until the body lines on the cab and bed line up. Very cushy.

It seems pretty doable to make blocks to go where the leaf springs are, taller to serve as lowering blocks at the same time. The left and right links would go from the front of the links to the front leaf spring mounts. The back of one would mount a panhard bar.

Mounting coilovers would obviously require something stronger than just putting a bayonet mount through the floor. After all, air shocks have ruined more than one trunk floor.

[jaybee]

I continue thinking this through a little at a time. Upon wondering how much compliance a torque arm mounting bushing would require, it was a Team Smart moment when I realized old Pythagoras had the answer to my question. Assuming the thrust (side) links start out level as they should, a2 + b2 = c2 tells us that a 24" thrust link and 2 1/2" of suspension travel up OR down would push the nose of the torque arm forward less than 0.14". At that point nearly any big, cushy bushing with the ability to pivot around its center would work. Probably even something like a Ford strut rod bushing, and they aren't as big as the Twin I Beam radius rod bushings or the pickup truck cab mount bushings. Undercar view of strut rod bushings