[Pampered-Z]

I’ll take a shot at this. I think I can cover the basics ( plus I'm on another 4 hour conference call and board out of my mind! ).

The rear suspension is made up of few different parts. A 3rd and 4th gen have what is basically a 3 link suspension.

First, all of the factory parts are stamped steel, rubber bushings/grommets. Adding additional HP or traction and normal wear and tear over the years cause the parts to loss their effectiveness. Basically the rubber deteriorates and the stamped steel bends. Also the factory is giving you more middle of the road settings. They are giving you fair traction, handling, ride comfort and limit road/suspension noise. So changes that add to one will detract from another. So after market is stronger and used poly bushings that give better control, but making your car hook or corner better will often effect ride comfort. A drag racing suspension is not meant to corner well, and a road course suspension isn’t good for drag racing.

For the sake of making this easy, all aftermarket parts will have poly bushing which are better then rubber, the trade off is the since poly is “stiffer” so does the car ride become stiffer as more parts are added. But hey, Who bought their F-body for a smooth ride?
Spherical ends replace poly, are more pure race, harsher ride, more noise. How much is too much is personal preference!

1) Torque Arm. It’s basically a lever to apply the engine power and somewhat uses the cars own weight car back onto the rear, mostly it keeps the rear/trans aligned. This is a piece that mounts to the rear center section and to the trans. As you apply power the front facing part of the rearend or pinion wants to rotate upwards. In effect the power is rotating the rear instead of the tires. The torque arm keeps the rear at the proper angle and helps the power go into rotating the tires, nor the rear. A stock unit keeps the factor setting which I think is around -1 degree? This Pinion angle is the difference between the output of the transmission to the angle of the input to the rear (or yokes ). The U joints allow the drive shaft to rotate smoothly with each end at a different angle. The more angle you have the more stress you place on the joints. At a point the stock stamped steel can deflect or bend causing you to loose traction or not apply the power as fully to the rear wheels. An after market unit is stronger, and many are adjustable so you can change the pinion angle. As an example, at -2 or -3 degrees you can get better traction, but you add wear to you U joins.

2) Lower Control Arms (LCA) The control arms locate the rear front-to-back, keeping the rear tires square with the front tires so the car tracks straight. Again, as you add power the wheel getting more traction will want to move forward faster then the other wheel, in effect twisting front to back. They are also a pivot point for the rear. And again, worn rubber bushing can cause bouncing and such. Problems with wheel hop can occur. Again, aftermarket are stronger some are adjustable, but adjustable have a special use, moving the rear forward/backward effect the driveshaft length. If you don’t need adjustments, don’t but them!

2A) Because the LCA is the low pivot point, if you change the car height (lowering springs) or have added power you may want to change the pivot point. LCA relocation brackets are installed to allow you to do this. Lowering the pivot point will reduce the deflection as the rear rotates as you move the pivot point further from the axle.

3) Pan hard rod. There are actually two, an upper and lower. The key one is the lower. The lower pan hard rod is used to center the rear right to left and is a pivot point based on the height of the car. Again, as the car lifts or squats, or is lowered the pan hard rod will move the rear side to side. After market allow you to adjust the rear better.

4) Sway bar. Controls the roll or pitching of the body. It keeps the car from leaning to one side and somewhat front to back. In straight line racing, the front sway bar is not so important, most remove it. But the rear still has value as it assist in keeping both rear tires planted equally. Most stock sway bars are hollow and bend/flex. After market and solid. Much stronger and some use alternate mounting locations. In the case of something like an S+W swaybar, allot better control, less ride comfort.

5) Shocks/Springs: Springs soften the ride and keep the car at a certain height, the shocks dampen the bouncing. In straight line racing, you want the front soft so the car “rocks back”, known as weight transfer. This is to help plant the tires. The rear shocks should be firmer. Now, there is a line you can cross. Not enough of this transfer and you don’t get as good traction, too soft and the car can bounce and loose traction. After market shocks and springs allow you to adjust and fine tune this movement.

Not a factory piece, Spring air bag.... If you even watch a car launch the body tend to lean towards the passenger side, the torque is twisting the car and basically lifting the driver’s side off the ground. A cheap trick is to install and air bag into the passenger side rear spring. This helps to keep the spring from compressing as much, keeping the car more level.


Hope this helps and makes some sense?

JB