5.0 Mustang & Super FordsHow To Chassis Suspension
Shelby GT 500 GMS Suspension - For the Greater Grip
We Give Shelby's GT 500 'Stang A Complete Suspension Revamp With Granatelli's S197 Chassis Kit
Horse Sense: C'mon now, you don't really think this new, "ultimate Mustang" is gonna be the one that enthusiasts don't mess with, do you? Puh-leeze!
It looks as though companies in the automotive aftermarket have finally caught on that proactively producing performance products for Mustangs is a good idea. We remember the mid-'90s when, despite having years of forewarning about an "all-new" 'Stang with an "all-new" modular powerplant, many companies that served us killer parts for Fox 'Stangs lagged severely when it came to making SN-95s run wild and handle like Formula1 cars.The period was frustrating, to say the least.
The tables turned, however, with the advent of the '99-'04 GT and '03-'04 Cobra. The folks we count on for hooking up our rides began developing great parts before the New Edge cars hit the dealerships, and continued that practice immediately after Ford announced there would be another all-new Mustang for 2005.
There is a lot to be said about the aftermarket hitting the ground running when it comes to Mustang technology. For many years it has been a good thing, and in the case of S197 Mustangs, it has actually been a great thing. Tuning programmers, cold-air-intake systems, "The Big Three" power-adder systems, camshafts, exhausts, torque converters, suspension pieces, wheels, and tires-it's all there for the latest 'Stangs, and the cars are barely two years old.
The '07 Shelby GT 500 is the latest rage in 'Stangbanging. With a blown 5.4 that pumps out 500 flywheel horsepower, as well as exterior styling and badging that makes it unique, it goes well beyond being a simple Mustang GT. In some ways-thanks to us and scribes from other enthusiast magazines-it carries a price tag that supports this feeling. Joe "JR" Granatelli Jr., owner of Granatelli Motor Sports of Oxnard, California, and the owners, executives, and technical wizards from several other aftermarket providers have written the big checks and purchased Shelbys-the new cars are also commonly referred to as GT 500s by members of the 'Stang Nation-strictly for research and development purposes.
GMS is known for its innovation and development of new Mustang products, so we can't say we were surprised when JR called and told us about the mods being made on his GT 500, only days after he had taken delivery. While a full, 3-inch exhaust system (PN ES-0530) was installed right away, JR told us his Shelby was also slated for a suspension upgrade.
Since we were anxious to get another up-close look at one of these new 'Stangs (Editor Turner spent two days looking at Shelby GT 500s and detailed his impressions in our August '06 issue, "Muscle Star," p.46), we arranged to perform the suspension installation at Extreme Automotive in Canoga Park, California. There, Saul "The Surgeon" Gutierrez and GMS-newcomer Jim "The Pride of Cleveland" Lucas took on swapping the GT 500's stock suspension for GMS's "1g" S197 chassis components. JR refers to the setup as "1g for 2Gs," meaning enthusiasts can purchase the popular 1g suspension for about $2,000. The kit includes billet camber adjusters, subframe connectors, an A-arm brace and rear shock-tower brace, driveshaft loops, sway bars, rear lower control arms, upper third link, variable-rate lowering springs, Tokico D-Spec shocks and struts, and a Panhard bar/brace setup-a good price for such an extensive collection of parts.
With the 1g suspension system installed, JR's car has a considerably lower stance, and based on similar testing that has been done with S197 suspensions, we're confident the dropped ride height and additional bracing will improve the GT 500's handling characteristics.
Keep in mind that a suspension upgrade such as this takes a full day to complete and some welding is required. We recommend you commission a qualified 'Stang shop to take care of it, as the job could be more time-consuming and frustrating if it is attempted as a driveway project.
Granatelli Motor Sports engineer Jim Lucas (left), Saul "The Surgeon" Gutierrez of Extreme Automotive (center), and Joe "JR" Granatelli Jr. (right) wasted no time taking stock suspension parts off this '07 Shelby GT 500, and replacing them with the GMS "1g for 2Gs" suspension package.
The car is based on the S197 platform and despite its blown, Four-Valve, 5.4 supercar powerplant, it rides on a similar suspension found on '05-'07 Mustang GTs. It is power mixed with a stock suspension (front: Reverse-L Independent MacPherson strut with 34mm tubular antiroll bar; rear: Three-link with stamped lower control arms, coil springs, Panhard rod, and a solid 24mm antiroll bar), leaving a lot of room for improvement. We think this type of project is a good idea, as the upgrade will bring the car's ride height down considerably, reduce body roll, and eliminate the push in steering we detected when the car was driven aggressively. Shelby GT 500s are shod with Goodyear Eagle F1 255/45ZR 18-inch tires in the front and slightly fatter 285/40ZR 18s in the rear. GMS's 3-inch, free-flowing exhaust system (PN ES-0530) is also shown in this photo.
Jim adjusts the lower control arm to the same length as the stocker. GMS lower arms feature super-strong, forged chrome-moly ends as opposed to welded ends, and help control wheelhop and flex. The street arms used for this project include urethane bushings, but GMS also offers rod-end-adjustable race versions of its lower control arms.
The GMS lower control arms require mounting plates (two-position-adjustable) that are welded to the axletubes on each side of the rear, and serve as extensions of the factory control-arm housings that create a more aggressive angle.
Jim tightens the arms once they've been final-adjusted, lubed, and the flat washers (one per side) that fit between the bushing and housing are in place.
Jim installs the floor plate for the rear driveshaft loop. While these pieces can be snaked into position with the exhaust installed, we recommend dropping the X-shape crossover for adequate clearance and an easier go of it.
The driveshaft loop is a four-piece assembly for the front and rear shafts.
Saul and Jim mock-up the subframe connectors and Saul welds them into place.
Both the GT 500's undercarriage and the GMS connectors require a liberal amount of cleaning with a mild-grit sanding disc in the areas that will be welded.
The stock Panhard rod is replaced with this beefier, adjustable piece and tubular brace. As it does with the lower control arms, GMS uses urethane bushings in this street setup, but Panhard rods with adjustable rod ends are also available for race applications. Note the Panhard rod relocation bracket, which sets the rod back slightly from the stock position. The Panhard rod helps reduce wheelhop and chassis flex, and also allows for properly centering the rearend under the vehicle.
Jim installs the variable-rate (90-160 pounds) progressive rear coil spring. The springs help lower S197s 1.55 inches in the front and 1.40 inches in the rear.
The rear shock-tower brace must be positioned prior to final installation.
Saul welds each mounting plate completely around the shock towers with the OEM shock absorbers still in place.
Once this is completed, the new Tokico D-Spec (Damping Specific) adjustable rear shocks are installed.
Using the GMS camber plates as templates, both Tokico D-Spec front struts must be marked and modified to allow for proper back-and-forth movement (camber adjustment).
Replacing the front strut and spring assembly is straightforward, but a spring compressor is required for installing the spring on the strut. GMS uses a variable-rate (295-405 pounds), progressive spring up front that will drop the front end by about 111/42 inches.
The camber is adjusted to 3.5 degrees negative.
This bar bridges the gap between the A-arms up front, which helps limit flex in any lowered '05-'07 'Stang.
The "1g for 2Gs" package features this stout front antiroll bar (GMS calls it a sway bar) and billet mounts. This bar is a direct replacement for the stock piece, as is the rear antiroll bar. With its larger diameter it does a much better job of reducing body roll to nothing, and it will make taking deep corners in a hot 'Stang a lot more fun.
Although it was late and daylight was long gone, we managed to get this photo of the now-lowered Shelby GT 500 before it was rolled out of the shop. With a drop of 1.55 inches in front, 1.40 inches in the rear, and a tighter, better-handling suspension, this ride is bound to be a straight-up blast when it's taken through the canyons at above-the-limit speed. Remember-a wheel alignment is mandatory when front struts and springs are replaced.