Muscle Mustangs & Fast Fords
Suspension Upgrade - Project Redheaded Step Child Part 5
Project RSC gets maximized with a new suspension, wheels, and tires.
While the K-member was off, we replaced the factory steering shaft with a solid version to further improve steering response, which also eliminated an annoying interference problem between the factory shaft and the Hooker headers.
After taking the measurements (the positioning is critical), the K-member was bolted in place along with the remainder of the front suspension components. After the front was completed, the MM guys went back to the rear to install the torque arm and adjustable rear swaybar, though like the front, the endlinks were not attached until after it was time to scale the car. Since we have big plans in the powerplant department, we decided it was prudent to go with the heavy-duty torque arm. The torque arm required suitably strong (weld-in) subframe connectors, proper lower control arms (that resisted binding), and a sturdy Panhard bar-all of which were part of the Maximum Grip Box but must be used if installing the torque arm on a Mustang equipped with other brand suspension components.
According to MM, we could expect a dramatic improvement in traction, both leaving the line and exiting a corner, thanks to replacing the bind-prone, four-link factory rear suspension with the torque-arm-enhanced three-link.
Combined with the Panhard bar, the torque arm eliminates the upper control arm attempting to perform double duty (controlling axle wind-up and locating the rear axle), something they fail at on both counts. The torque arm is positioned to eliminate axle wind-up, leaving lateral control up to the Panhard bar. The trick to installing the torque arm was to measure and adjust the pinion angle (using the supplied shims) before bolting the arm to the rear differential. The rear swaybar was the last component to be installed-the welding made easy thanks to the supplied orientation plates that properly located the (weld-in) mounts.
After the rear swaybar was successfully installed, it was time for alignment. Since the goal of any suspension upgrade is to improve the contact patch between the tire and road surface, the alignment specs are critical. Were we attempting to maximize the handling for the track, we might get aggressive on the alignment specs, jacking maximum caster and as much as 3.5 degrees of negative camber (with just a hint of toe out), but these specs would quickly ruin a set of tires (or at least the inside edges) on the street. For the street, the MM gang dialed in the alignment specs at 3/4 degree negative camber, nearly 7 degrees of caster, and 2 mm total (1 mm per side) toe in. On the scale (corner weight scales), the '96 GT checked in with a total weight of 3,562 pounds with driver and full of fuel, offering a front-to-rear spilt of 55.6 percent (front) and 44.2 percent (rear). The diagonal readings (LR to RF and RR to LF) were dialed in (by adjusting the ride height slightly) to achieve a near-perfect balance of 49.7/50.2 percent. After hooking up both swaybar endlinks, Project RSC was officially Maximized.
We didn't have to take the car more than 10 feet to recognize the improvement. A quick drive on the official MM test loop revealed the new suspension had literally transformed the Mustang. Where the (well-aged) stock suspension seemed to provide no other benefit than keeping the body from rubbing the ground (but not equally front to rear), the Grip Box made the car feel whole again. Gone was the feeling of having the front and rear suspensions arm wrestling to see which would lose grip first, replaced by unity, solidarity, and coopera-tion between the two ends. The Mustang now felt secure and confidence-inspiring, allowing balanced four-wheel drifts (though at a much higher speed).
Where the stock suspension was limiting the tire adhesion, the reverse was now true with the Grip Box. The generic tires were now limiting the effectiveness of the suspension. The tires give up just as the suspension is getting started-a situation we cured with a set of Nitto 555 18-inch tires and Ford Racing Cobra R rims (9.5 inches wide). Now, we can finally enjoy driving the Mustang thanks to the newfound grip. Our only complaint is that the new suspension makes the 240 hp feel terribly inadequate.