The lower control arms install...
The lower control arms install very easily; it's just a matter of unbolting the stock arm, and swapping in the new one. Eric Norrdin of Global West performed our install, and he suggests that if the bolt holes don't line up, lift the frame a bit to rotate the axle housing.
The joints for Global West's lower control arm set (part No. TBC-13) also use a high-misalignment spherical bearing on the chassis end, but a Del-a-lum bushing on the axle side. The Del-a-lum bushing is a sandwich of durable Delrin and aluminum. Delrin offers a low-friction surface that's quiet and wear resistant, yet has very high resistance to deformation, making it ideal for this sort of thing.
So the bones of our Laguna's rear suspension consists of Global West's TBC-37 upper control arms with the SP-47 bearing kit, and the TBC-13 lower control arms. But maintaining the proper geometry is only half the battle. None of these things matter in the least if you can't transfer the load from the tire to the ground. Springs and dampers (shock absorbers) are responsible for that. In a heavy car like the Laguna, the right springs and shocks can make a huge difference.
The actions of a spring and a damper are intimately intertwined. A spring stores road energy--heavy springs store and release this energy more quickly, and light springs do it more slowly. On the racetrack, it helps to store and release the energy quickly, so the tire can stay in contact with the road, and act on the car. The only downside is that a spring oscillates, and that oscillation needs to be controlled by a damper. As a rule, a stiffer spring needs a stronger, more viscous damper to control oscillation. By extension, lighter springs need less dampening to control them. So springs and shock absorbers need to be conceptualized as a matched pair, whereby the spring is optimized for the road and the car's intended use, and the shock damper is subsequently designed to control the spring oscillation.
The new Global West upper...
The new Global West upper control arms will have to be adjusted for length before being installed. The old ones can be used as a template by using guide bolts. Note the hex-sided center section, for easy fine-tuning on the car. The jamb nuts keep everything locked, but should be loosened for adjusting the length.
Springs are rated in pounds per linear inch of deflection. In the case of our stock Laguna spring, it takes about 125 pounds of force to compress the spring 1 inch. We substituted this for a Global West spring (part No. S-61) with a rate of 160 lb/in, which should allow the tires to follow the road contour at high speed much better. The stock shock absorber, however, cannot completely control the higher spring rate, and the oscillation that goes with it, so we brought another expert into our loop: QA1 Motorsports.
We decided that to get the most out of our improved suspension, we needed a double-adjustable shock, meaning that the amount of damping force can be set independently for both compression (when the tire is shoved up into the fender by a bump), and rebound (when the spring extends the tire downward, as with a pothole or dip). QA1's Stocker Star double-adjustable shock was the answer. If you have a Laguna or any '73-77 GM A-body, the proper double-adjustable Stocker Star shock for the rear is a part No. DTC-1661P, which has the proper range of travel for a near-stock ride height, or slightly lower. We discovered that due to our dropped ride height (we lost track when it got to be more than 2 inches) a shorter shock was required, so we substituted part No. DTC-1915P. Had we used the longer shock, we would've damaged it internally, rendering it useless. (Since Global West is a QA1 distributor, you should consult with their staff about your ride height so they can recommend the proper QA1 shock.)
The rearend bearing kit is...
The rearend bearing kit is what makes the Global West system work so well. It eliminates any deflection or play in the upper control arm by way of a chromoly, high-misaligment spherical bearing. These are fitted inside the rearend housing in place of more customary rubber bushings.
Before we get on with the installation, one word about antisway bars. Our Laguna did have a rear bar from the factory, which we opted to remove. I've found that with a sufficiently stiff suspension all around, the rear sway bar becomes less crucial, and can even hurt handling. A rear sway bar in conjunction with a stiff rear suspension can cause oversteer, although intuitively you wouldn't think so. The reason is that a modest amount of rear body roll can actually help plant the outside tire earlier in the corner, and improve bite. A stock-type sway bar like ours is mounted to the control arms, with most of its mass being unsprung weight, so if we do elect to put one back on at a later date, it will be mounted to the chassis, and connected to the axle with end links.
Of course, no rear suspension can operate properly without a matching front suspension, and we haven't forgotten about that. The day following our rear suspension installation at Global West, we came back to do the front half. The difference is like night and day. We were concerned that it might be too stiff, but when we hit the road, we found it quite compliant, only much more sporting. Probably more than any other thing, we noticed that the car felt significantly lighter, even though we know otherwise. Where it would wallow and porpoise over bumps and dips, it's now tight and taught. All we lack is some time on a road course to tweak our QA1 shocks. Next month, we'll take the wraps off our Global West front suspension!
|WHERE THE MONEY WENT |
|DESCRIPTION: ||Part No.: ||Price: |
|Lower rear control arms ||TBC-13 ||$397.14 |
|Upper adjustable rear control arms ||TBC-37 ||$310.75 |
|Rearend bearing inserts for upper control arms ||SP-47 ||$290.27 |
|QA1 double-adjustable shocks ||DTC-1915P* ||$559.95 |
|Rear lowering springs ||S-61 ||$141.25 |
|Total: ||$1,699.36 |
|*needs eyelet kit |
Before you install the Global...
Before you install the Global West rearend bearing kit, you need to chisel out the old upper control arm bushings. An air chisel works great for this.
Here's where it all comes...
Here's where it all comes together. Insert the bearing in one side of the control arm anchor tab, and screw on the locking ring from the other side. Use the spanner wrench (included in the kit) to pull the bearing all the way in, and snug it up good. You should get a nice interference fit with zero play.
Bolt the new Global West control...
Bolt the new Global West control arm to the chassis, then line up the holes on the rearend. Now is a good time to eyeball the pinion angle (with full weight on the rear), and make any adjustments you may need to the length of the upper control arm.
Swapping out the springs is...
Swapping out the springs is next, and this was relatively easy for us since our old ones were cut, and the new ones are short to start with. At this point, the old shocks have been unbolted to let the rearend droop, and the frame has been lifted to unfetter the springs. With the old cut springs still in, we had taken a height measurement from the ground to the fender lip as a reference. Using that as a guide, we checked the new ride height, and cut the new springs to achieve the same height.
Here's the real meat of the...
Here's the real meat of the QA1 double-adjustable Stocker Star shock absorber: the independent valving for compression ("C") and rebound ("R"). QA1 says there are 24 positions for each dial, giving the double-adjustable Stocker Star a total of 576 possible settings. We actually found that there are 31 detents on the compression dial, and 33 detents on the rebound dial. Starting from the "zero" setting, we clicked it up to "4" on the compression, and "8" on the rebound. This produced good results on the highway, but we'll be firming it up for the track.
Bolting in the new QA1 shocks...
Bolting in the new QA1 shocks was a cinch. (You want to do this after the spring swap.) We oriented the adjustment knobs where we could easily reach them.
Here's the Laguna's finished...
Here's the Laguna's finished rear suspension. The rest of it looks pretty grim by comparison, but at least it's merely dirt, and not rust. In a year, you won't be able to recognize it as the same car.