Our '93 Mustang has served well, doing battle on both coasts—New York City and LA, in particular—over the past several years and 50,000 miles. While ride quality hasn't degraded noticeably, the handling characteristics certainly haven't improved with age either. As reliable and enjoyable as this Mustang has been, its ride quality and cornering ability left much to be desired since the first testdrive.
Our '93 Mustang has served well, doing battle on both coasts—New York City and LA, in particular—over the past several years and 50,000 miles. While ride quality hasn't degraded noticeably, the handling characteristics certainly haven't improved with age either. As reliable and enjoyable as this Mustang has been, its ride quality and cornering ability left much to be desired since the first testdrive.
Certainly, Fox-chassis Mustangs can be made to carve corners with the best, but we harbored a fear of modifying the car that stemmed from a perception that ride would worsen as a result. How can a car be made to handle better without stiffening the ride? The stipulation that the 'Stang would not be lowered narrowed our regions of flexibility even further. We weren't leaving ourselves much wiggle room on this one.
Knowing that Hotchkis Performance had done extensive testing for product development on Fox Mustangs, we presented our dilemma to proprietor John Hotchkis, who suggested that we establish a baseline before changing anything. But before we could hit the tarmac, we'd have to outfit the Mustang with fresh rubber, as our bargain-outlet donuts would surely skew the test results.
Since the Mustang was to remain a daily driver, it needed to roll on pragmatic rubber. Maybe it's that East Coast influence running through the staff, but we opted for an all-season design—perhaps a bit removed from what the SoCal climate warrants. When we spoke to the tech guys at Dunlop Tire, they assured us that the Z-rated SPORT4000 A/S series would meld real-world traction with high-performance response. Though our Mustang left the factory with 225/55R16s, we upgraded to 245/50s and retained the 7-inch-wide factory alloy rims.
During the first session, Hotchkis split driving duties with employee Scott Gillman, and the feedback coincided with what our butts had been detecting all along—marginal performance. Our 0.80g average on the skidpad and 53mph speed through the slalom could best be described as mediocre, thus leaving plenty of room for improvement.
Hotchkis was impressed with the all-season Dunlops. With 40 psi in the front and 35 in the rear, the tires seemed to be rolling right to the edge of the shoulders—just as they should. The test site we were using had "real-world" surfacing, including bumps, dips, cracks, and so on, so our tires were right in their element. The most obvious flaw in the slalom behavior was its tail-wagging tendency … that is, the body would sway radically from side to side over the rear axle. Hotchkis claimed he had a fix. We took the car to his Santa Fe Springs, California, shop and laid out a plan.
Hotchkis recommended his rear control arms, which are constructed from tig-welded 0.120-inch-wall steel tubing and fitted with polyurethane bushings. They offer a dramatic increase in torsional rigidity over the stock steel stampings, and the stiffer bushings eliminate much of the deflection realized with the rubber factory pucks, especially the large, oval bushings at the front of the stock lower arms. Hotchkis also recommended his Delta Camber/Caster plates which replace the factory upper-strut mounts and provide additional camber adjustment (three degrees overall) and 5 degrees of caster adjustment (the factory provides none). They are also equipped with polyurethane bushings to limit deflection and still provide isolation from road noise.
Finally, Hotchkis suggested new dampeners, as an aid to handling and ride quality. We were skeptical about the ride part of the equation but quite adamant about the adjustability option. Tokico Illumina struts and shocks provide five levels of damping force and are externally adjustable with detents and numbered dials, so there's no guesswork involved in setting them. They're also designed to provide adjustment on both compression and rebound simultaneously—a fairly unique feature. What's really cool is that, according to the literature, Tokico intends these struts and shocks to be used for "road racing, autocrossing, drag racing, or just driving to the store," which are all uses our Mustang will likely see. We also learned that the Illumina dampeners are part of Tokico's Advanced Handling Suspension Kit, which also includes performance springs; though sorely tempted, we stayed true to our self-imposed "no lowering" rule.
Once we had gathered all the items, Paul Yniguez, who handles new-product development for Hotchkis, took care of the labor. The job is a fairly straightforward remove-and-replace operation, and we figure Yniguez could have done the whole thing inside of two hours, had we not slowed him down for photos. We used a lift, but a pair of sturdy jackstands and a good floor jack would have sufficed.
We had the alignment set for-0.5 degree camber, a mild alteration of the factory zero-degree spec. Caster was set for factory spec. On the street, with the shocks set on 1 all the way around (full soft), the most noticeable change was the extra noise coming through the rear arms, although most of this seemed to come from our faulty ring-and-pinion. Hard acceleration demonstrated the increased responsiveness in the rear suspension, and at the softest setting, the shocks felt a touch firmer than stock.
Returning to the Hotchkis test site revealed more improvement than we had anticipated. Slalom speed rose to an average of 61.36 mph. We attained this with the shocks set at one and three, front and rear, respectively, and Hotchkis felt that the car would have responded to firmer shock settings on a smoother surface. Skidpad figures improved to 0.86 g, and our Dunlops survived the torture test admirably.
If successful suspension tuning for the street really does revolve around narrowing the gap between skin-pulling cornering and blissfully numb cruising, we scored big time. We traded a little extra road noise and harshness for a significant improvement in performance, and we haven't even fully explored the possibilities of this combination … yet.
Baseline runs revealed lackluster handling. John Hotchkis organized the test session and shared driving with product developer Scott Gillman. Our best slalom average worked out to 53.69 mph; the average skidpad pull was 0.80 g-about what a new Crown Victoria will do.
The Hotchkis Delta Camber/Caster plates allow additional camber and caster adjustment to enhance handling; lowered Mustangs usually require these to regain factory alignment specs. One of their endearing features is polyurethane bushings instead of spherical bearings, which isolate chassis noise.
Letting strangers mess with our cars makes us nervous, and bargain-outlet tire shops are notorious for accidental mishaps. That's why we use Flip's Performance Tire in Van Nuys, California. The company knows its stuff. Sixto Hernandez mounted and balanced our Dunlops and taped the weights on the inside of the rim to avoid damaging the clearcoat.
The rear end must be supported to perform the control-arm install, and though we used a drive-on rack with built in jacks, jackstands and a floor jack will cover you. Paul Yniguez began by unbolting the shocks (all four of them) and loosening the control-arm bolts. He also removed the factory sway bar.
With the control arms loose and the shocks disconnected, Yniguez manipulated the axle to unload the springs, which he then carefully removed.
The upper-control-arm kit includes new polyurethane bushings for the differential housing. Hotchkis considers them optional and claims that they increase the stiffening as well as harshness. We left them out for now.
Hotchkis includes new control-arm hardware and a special grease to lube the bushings. The arms have grease fittings for maintaining lubrication. Yniguez did the uppers first, which are already adjusted to the stock length-nonadjustable uppers are also available. To keep the axle in place, he replaced them one at a time.
Hotchkis' heavy-gauge boxed construction and smaller, stiffer bushings will firm up the rear suspension significantly compared to the factory stuff. In fact, Hotchkis says these arms eliminate the need for the original quad shocks.
Once the arms were in place, Yniguez reinstalled the original springs using the factory rubber isolators. The original sway bar was reinstalled on the brackets of the new lower arms.
With the lower mount already undone, Yniguez removed the nut, which is accessed through the trunk, from the top of the shock-mounting stud. The new ones (which come with new hardware and bushings) slipped easily into place. Numbered dials allow shock settings to be read at a glance.
At front, Yniguez began by measuring the position of our upper strut mounts, so that we could maintain the current alignment close enough for the trip to the alignment shop. He measured from a mark on the firewall and then from a mark on the inner fender.
Yniguez supported the control arm to contain the spring and removed the brake caliper to gain unrestricted access to the two bolts in the lower strut mount.
Removing the nut from the top of the strut shaft allowed the struts to drop right out. After that, Yniguez unfastened the three nuts for the strut mount-if your Mustang has never been aligned, there may be a Pop rivet holding the camber adjustment. Drill it out to remove the mounts.
Comparing the Delta plates to the factory strut mounts illustrates the adjustability and the extra support they offer to the strut, which will ward off deflection and improve suspension responsiveness.
The Delta plates bolt right in. Yniguez left the fasteners loose until he installed the struts.
After the realignment with -0.5 degree camber (stock is zero) but leaving the other settings stock, we went back to the test facility. After experimenting with tire pressures and shock settings, Hotchkis and product engineer Gary Pink-ley found the best slalom numbers with the front struts at full soft (one) and the rears at three. A smoother test surface would have merited stiffer settings. Tire pressures worked best at 40 and 35 psi. Our best slalom average was about 8 mph faster than stock. Skidpad figures improved to 0.86g (0.80g stock).
The Delta plate kit includes upper strut bushings, a dust boot, and spacers to properly position the strut shaft. The variance in positioning is more of an issue with lowered cars; we only had to make sure the tops of our struts didn't contact the hood.
