5.0 Mustang & Super Fords
2008 Ford Shelby GT500 Suspension Upgrade - Project Vapor Trail
Steeda's Coilover Suspension And Watt's Link Transforms Project Vapor Trail's Handling (And Looks)
Horse Sense: If you don't want to go with the fully adjustable coilovers, Steeda offers a non-adjustable solution in the form of its GT500 Handling Pak (PN 555-2373; $1,499.95), which features Tokico D-spec dampeners, Steeda Sport springs, Steeda swaybars, and a Steeda strut-tower brace.
Since the moment I laid eyes on Project Vapor Trail, my '08 Shelby GT500 project car, our ace freelancer, Dale Amy, has been needling me about the car's lofty ride height. It's a tough audience around the 5.0&SF ranks, but I had to agree. We are a jaded bunch to be sure, but there hasn't been a stock Mustang yet that could go for a bit of lowering to sharpen its looks and handling, and the GT500 is no different.
Though a move to larger wheels and tires ("Limited Tradition," March '09, p. 102) went a long way toward improving PVT's looks, it was time to take its looks to the next level while improving the car's handling. If you've ever had the good fortune to pedal a GT500, you'll quickly learn that the car's off-the-showroom-floor handling is a bit compromised. It does well enough getting around the corners, but the weight of the iron 5.4 and the spring rates-spec'd in for 50-year-olds-makes the car plow when pushed.
Having wheeled in the superb GT500KR, I was impressed with its balance of handling and ride quality. Of course, the Ford engineers made a point of equipping the KR with lightweight 18-inch wheels for better performance and handling. Heading for style on the street, PVT is rolling on 20-inch CS69s from the Carroll Shelby Wheel company, so I was in the hunt for a suspension system that would maximize PVT's handling, while minimizing the impact of the larger wheels and lowered ride height on my backside.
After some rigorous research I fancied Steeda's adjustable suspension system for the GT500. Not only does this system allow you to tweak the ride height to your liking, but coilovers, by nature, allow you to cherry-pick your spring rate for its intended use. After chatting it over with Steeda main man Dario Orlando, he assured me that they had just the recipe for my needs. Having had great luck with Steeda's gear on my '98 Cobra, it didn't take much convincing to have me barreling down the Florida Turnpike to Steeda's Pomano Beach campus for a suspension upgrade.
Of course, the parts list was a bit more involved than just the coilovers, but the end result is flat-out astounding. PVT carves corners, the front end feels lighter, the rearend is locked down, and most important of all, it rides better than you could ever imagine for a slammed S197 on 20s.
Unfortunately, the lightweight radiator support wouldn't fit the GT500, but by the time you read this, Steeda will no doubt have a version that does.
Before getting into the thick of things, Steeda shop manager Steve Chichisola measures the ride height and pinion angle of our stock setup. Yes, Dale, it was really that high, leaving a good 2 inches between the fender and the tire. Plenty of room for snow chains, but PVT isn't going to see snow while I own it. With the stock measurements noted, Steve and Steeda tech Matt Bouyea began tearing into PVT's virgin suspension.
Steve started by pulling off the stock brake caliper and rotor. It's not necessary to disconnect the brake hoses to install the suspension gear, but since we are also adding Steeda's brake upgrade kit, Steve removed the brake hose, capped the line, and removed the complete caliper assembly. If you don't disconnect the hose, be sure to securely hang the caliper from the car so you don't damage the hose.
Since the stock front dampers feature a coilover design, it's a simple process to remove the stock parts. Support the bottom of the spindle with a jack; then remove the four bolts atop the strut tower. Slowly release the spring pressure with the jack, and detach the two bolts holding the strut to the spindle. Disconnect the tie-rod end and remove the entire assembly.
Here's a comparison of the bulky stock spring and strut and Steeda's sleek, adjustable coilover strut set, fully assembled with the heavy-duty Steeda upper-strut mount. Its slim shape and good looks are a minor part of the Steeda coilovers, which allow for infinite adjustment of compression and rebound, offer the expected ride height and spring-rate adjustments, and are designed around Steeda's rugged, quiet spring mount, which can withstand more spring rate without popping. Obviously they are built to perform, but Steeda is so confident in the quality of these parts, they pack a lifetime warranty. That kind of guarantee makes it a lot easier to shelve the stock gear and go for better performance.
When you lower your 'Stang, it throws off the car's suspension geometry by lowering the roll center. To correct that deficiency, Steeda developed the taller X5 balljoint, which raises the roll center to its proper height, thus reducing bodyroll, sharpening handling, and keeping more of the tire on the road. Good stuff, but installing one requires a bushing press to push the old ball joint out of the control arm. With the same press, you can force the new ball joint into the control arm. After it's in place, install the grease fitting. The balljoint is pregreased, but you can use the fitting down the road to maintain the bushings.
More familiar to those who have lowered a few Mustangs is a bumpsteer kit. If you don't correct bumpsteer by correcting the height of the tie-rod end, the wheel will actually make slight steering movements as the ride height changes with braking, cornering, or bumps. Naturally, Steeda's bumpsteer kit corrects these mathematical ills and helps keep your car tracking straight. Installing them is as simple as removing the old tie-rod ends and installing the Steeda kit. The detailed directions walk you through the minutia. Naturally you will need an alignment after all this work.
Here's a clear look at PVT's completely Steeda-fied front suspension in place. You can see how the X5 balljoint and bumpsteer kit work together to raise the roll center, while the coilover is anchored by the stout Steeda mount. The billet collar allows you to raise and lower the ride height based on your liking or the car's intended use. These parts are used on cars as diverse as Sutton High Performance's Renegade drag racer and Robin Burnett's NASA American Iron road racer. Suffice it to say that it should be plenty for PVT's street intentions.
To finalize the front end, Steve installed the braided-steel brake hose and slotted rotor from Steeda's GT500 brake upgrade kit. The hoses firm up the pedal feel, and the slotted rotors help shed gasses that build up between the pad and rotor, which is all said to improve braking. Let's face it though, most people upgrade the rotors because they look cool.
While the front brake upgrade is a simple remove-and-replace process, the upgrade for the rear requires a bit more work. That's because it spaces out the caliper to make room for a 13-inch rear rotor. This helps braking, as well as filling up those 20-inch wheels, which make the 11.8-inch stocker look miniature. To space out the calipers, first pull the rear axles, which means digging into the differential. Matt pulled the stock cover and got right to work. While this gave us the opportunity to replace the break-in fluid with some fresh lube, it would have been a great time to install a differential girdle, so keep that in mind if you are making this move.
With the axles out, Matt bolted on the billet caliper relocation brackets. These pieces are works of art, and place the stock caliper in the right spot without upsetting the factory functionality. Here he is installing the ABS sensor in the new bracket so everything will work just like stock, only better.
Matt followed up the brackets by reassembling the rearend, applying a fresh bead of sealant to the differential cover, and bolting it back on. While the cover cured, he moved to the braided-steel brake lines included in the brake upgrade kit. There are left and right lines, so make sure you grab the correct one for the brackets to line up with the mounting holes on the frame.
Matt installed the new rotor and bolted on the caliper before finishing up the brake-hose install. While the new rear rotor is larger, it's actually lighter than the stock parts, so it helps trim down some of that bothersome unsprung weight while improving braking. Notice that Matt cleaned off a bit of the rotor's anti-corrosion coating where the pad makes contact, as it ensures the rotors and pads will make nice right away.
While the adjustable suspension solution for the rear doesn't replace the factory dampers with true coilovers, it does add coilover-like functionality by adding this billet adjuster to the stock spring perch on the axle. A tab securely mounts the adjuster to the perch. Once in place, it can be adjusted with a spanner wrench just like the front coilovers.
With it in place, Matt adds our new spring to complement the already-installed Tokico D-spec dampers. To deliver my wish for better handling with great ride quality, Steeda main man Dario Orlando specified 175-in-lb front springs and 200-in-lb rear springs; the results were beyond my expectations.
I wanted to leave behind the dreaded wheelhop the GT500s exhibit when you lay down big power with the stock suspension, so new control arms were in order. However, I didn't plan on spending a lot of time under the car tweaking its suspension setting. As such, I chose Steeda's trio of chrome-moly S197 control arms. In the case of the upper, Steeda offers one for stock ride heights and one for lower ride heights. Naturally, this shorter-than-stock unit is the latter one.
A direct replacement for the stock piece, the chrome-moly Steeda upper control arm comes complete with a bumpstop, but be sure to install the aluminum spacers between the bushing and the upper mount. While the three-piece bushing in the mount is said to reduce deflection while maintaining ride quality, you do give up a bit on NVH with all the suspension gear in the form of a bit more noise. There is a slight clip-clop sound coming from the suspension when the rear suspension unloads, but given that my stereo is at concert volume most of the time, I rarely notice.
With the car on a lift, the lower control arms are an easy swap. The only trick is to be sure and put the wider side of the axle bushing toward the center of the car as the arms are side-specific. Matt greased the bushings with a liberal dose of waterproof grease to ensure a squeak-free install. Keen readers will also target the Steeda lower control-arm relocation bracket Matt bolted into place first. Since PVT is going low, these brackets are a necessity to restore the suspension geometry and ensure good traction. Once everything is bolted up and adjusted, these brackets are welded into place for maximum strength.
Before busting out the welder, Matt added Steeda's three-point framerail and torque-box brace, which bolts in using factory holes. While S197s are far stiffer than their predecessors, a little insurance isn't a bad idea when your ride is packing 600 lb-ft of torque and rolling on Nitto drag radials. These chrome-moly braces triangulate the inner framerails, outer framerails, and torque boxes. After bolting on the two braces, Matt sparked up the welder and secured the lower control-arm relocation brackets and three-point braces.
On the home stretch, Matt checks PVT's ride height, dials in our new weed-whacking ride height, and ensures the measurements are equal on both sides. Lift the car with a jack or lift to unload the weight, which makes it easy to adjust the height. Once the ride height is where you want it, lock the perch in place with the Allen-head set screw.
With the up and down in order, it was time to upgrade the side-to-side. Steve and Matt teamed up to mount the Steeda Watt's link to PVT's rear axle. While a Panhard bar is a huge improvement over the prior Mustang's lack of lateral axle control, it does give up some precision. One end of the bar is mounted to the chassis and the other swings up and down with the axle. A Watt's uses two bars, which move independently and eliminate the lateral movement that the Panhard bar would allow.
For those rare occasions that PVT might see the track, it seemed wise to put safety first and add Steeda's two-piece driveshaft safety loop, which uses existing bolts in the floorpan and transmission mount to position two loops over both halves of the stock two-piece driveshaft. You can install the loops without removing the driveshaft; on a GT500, you may need to slightly clearance two bolts on the transmission crossmember. It goes on easily, and you'll feel a lot safer knowing it's there. I do.
The Steeda unit clamps to the axle housing, so you have to unbolt the factory sway bar and remove the stock Panhard bar to make room and lift the Watt's into place. Once it's attached to the axle, the Watt's bolts to the chassis right where the stock Panhard bar attached.
Despite its impressive construction and handling benefits, it really is a straightforward install, and Steeda's detailed instructions walk you through the details and torque specs. Before clamping it all down, Steve used a digital level to make sure everything was parallel to the ground.
Once the Watt's was mounted, Steve and Matt were able to adjust PVT's rear roll center and center the axle in the chassis thanks to the Watt's adjustments.
While the car was on the rack, I noticed that the rearend was off-center from the factory, which was readily apparent thanks to the wider rear tires. Steve used a straight edge against the wheelwell to measure the space between the wheel and fender, and Matt easily dialed in the adjustments.
Being a full-fledged Shelby Melvin, I'm trying to keep as many stock parts as possible. I'm quickly running out of garage space, but so far, the stock speakers are the only parts to go in the trash. This latest round of mods produced a pallet full of stock gear. The new parts delivered a balance of a smooth ride and sharp handling that you wouldn't believe possible from a car slammed on 20s. Steeda's adjustable suspension could just be my favorite mod so far.
With all the suspension mods complete, Matt used Steeda's computerized alignment rack to dial in PVT for a proper balance of handling and tire wear. He even compensated for Florida's crowned roads with 1.2 degrees of camber on the passenger side and 0.9 degrees on the driver side.