5.0 Mustang & Super FordsHow To Chassis Suspension
S197 Suspension Upgrade - Apex Attack
Sharpening a Mustang GT’s suspension at the track
When word of Track Guys' High Performance Driving Event at Sebring International Raceway reached 5.0&SF headquarters, it seemed an ideal test venue for some suspension bits. But you know how we conduct testing here at 5.0 Mustang & Super Fords magazine. We couldn't just toss a couple of parts at the car, run a few laps, and call it a day. No, we consider it our responsibility to deliver hardcore technical detail for you.
With that strategy in mind, we contacted our friends at Steeda Autosports for help transforming our mild-mannered Mustang into a crazy cornering machine. As purveyors of quality suspension for over 20 years, we knew they were up to the task. Glen Vitale, Steeda's vice president of operations, came up with a crazy idea that was too fun to pass up. He suggested we install one upgrade before each track session so that we could evaluate how each part affected the car's handling.
Before heading to the track, we kicked things off at Steeda's full-service installation facility in Pompano Beach, Florida. There, technician Steve Chichisola installed a set of Steeda Sport springs, which lower the car 1 inch in the front and 1 inches in the rear. Then he replaced the brakes, front and rear with new OEM replacements from NewTakeOff.com for a reliable baseline. Next, he performed an "aggressive" street alignment with camber at -1.5 degree, toe-in at 0.13 degree, and caster at 8.0 degrees.
Steve wrapped up our pre-event preparations by performing a complete vehicle inspection, ensuring the Mustang was ready for flogging on the racetrack.
On the drive home, we could hardly believe the difference in the car's personality. The car stayed much flatter while accelerating, cornering, and braking. However, the lowered ride height didn't degrade the ride quality. Also, the new alignment settings obviously sharpened the initial turn-in. I used the two weeks following this initial installation to familiarize myself with the car's new handling characteristics.
As the big day arrived, we ran the first session at Sebring just as the car left Steeda two weeks prior to the event. It was stock aside from the Steeda Sport springs and performance-minded alignment. The car was surprisingly balanced. Handling was smooth and predictable. Although high-performance driving events are not actual races, we were impressed to pass several cars in this quasi-stock configuration. That says a lot about the performance potential of the S197 Mustang, and that of Steeda's Sport springs.
Unfortunately, the OEM brakes were our biggest limitation at that point. The brakes faded after one hard lap, which necessitated a more conservative approach in the slower corners. Still, we were satisfied with the baseline session, and we proceeded to the next step.
Following the first session, Steeda technicians Steve Chichisola and Matt Bouyea installed Steeda's adjustable front sway bar right in the Steeda pit space. This modification significantly improved rear traction. It stabilized the car with a tendency toward understeer, making it more comfortable to drive at speed. This allowed aggressive application of the throttle without concern that the rearend might step out unintentionally. In high-speed turns, the front tires voiced a bit of protest as they reached their limit before the rears, but the car could rotate with throttle-induced oversteer.
Back in the pits for our next modification, Steve and Matt installed Steeda's Competition Rear Sway Bar with endlinks.
Out on the track for Session 3, the difference was amazing! The car was much more balanced, flatter in high-speed corners, and it exhibited neither understeer nor oversteer. It went into an even slide when pushed to its limit, with the front and rear tires losing grip simultaneously. Steering response was incredible, but any carelessness on the throttle pedal kicked the rearend out easily. Most importantly, the car was much faster with both Steeda sway bars installed. In fact, it was so fast on the Steeda springs and sway bars that the factory brakes became a serious liability.
Thankfully, Session 3 was our last run of the day, so we had plenty of time to work on the car when I returned to the pits. Of course, by "we," I mean that Steve and Matt had the car apart in less time than it took me to hit the cooler for an ice-cold diet Pepsi!
First they installed Hawk Performance Quiet Slot front brake rotors. Next they installed Hawk Performance HP+ brake pads in the front and HPS pads in the rear. With the brake installation completed, the guys moved onto the rear suspension with the installation of Steeda's billet rear lower control arms with urethane bushings. After they reinstalled the wheels, I took the car to one of Sebring's parking lots to bed-in the new brake pads, per Hawk's instructions. With the brakes installed and bedded, and the lower control arms in place, we called it a day with plenty of time to get ready for the Track Guys banquet later Saturday night.
Following a brief driver's meeting Sunday morning, we were back on track for Session 4. As expected, the Hawk Performance pads and rotors drastically improved our stopping performance. The brakes were responsive, offering much more grip without being too grabby on the initial bite, and brake fade nearly vanished.
The unexpected surprise from Session 4 was how dramatically the Steeda lower control arms improved the handling. Honestly, this was the most perplexing test of the weekend for me. I know the factory control arms are not conducive to performance driving, and I've upgraded the lower control arms on many of my Mustangs in the past, but none of that prepared me for the results of this track session. The car was much faster around the track on the Steeda billet lower control arms. The arms reduced the vague, floating feeling in the factory rear suspension and kept the axle planted through the rougher sections of the 61-year-old track. The added stability allowed throttling down sooner and building more speed exiting the corners.
With so much more speed, the tires became the biggest limitation on the car's performance. Appropriately, our last modification for the Sebring test was the installation of 18x9.5-inch GT500 replica wheels from American Muscle, wrapped in 275/40-18 NT-05 tires from Nitto Tire.
Around the track for Session 5, the performance improvement took our Mustang to a new level. The increased grip of the Nittos allowed us to carry far more speed through the corners, which created new problems for us. The brakes, which had worked superbly on the factory tires, were suddenly being overworked at the speeds possible on the Nittos. We began to notice brake fade four laps into the session. However, unlike the factory pads and rotors, the Hawk brakes still maintained reasonable stopping power when they were overheated.
Speaking of brakes, the extra lateral grip caused the ABS module to interfere in connected corners with fast transitions. The factory shocks and struts were simply unable to control the weight transfer which unloaded the inside tires during cornering and caused the anti-lock braking to kick in. There was also a more pronounced wiggle out of the rear end on corner exits, tells told us the car needs an upgraded Panhard bar or Watts link. We were able to clock a lap time of 2:48 before returning to the pits, which is respectable for a street car on street tires.
Unlike our previous track sessions, we ran Session 6 with no changes from the session before. We used the outing to explore the limits of the Nitto NT-05s. Although they sport a 200 treadwear rating, their grip far exceeds the factory tires. We pushed the car as much as possible in an attempt to get it out of shape, and it was carrying so much more speed through the corners that it was running out of gear in four spots on the racetrack. The suspension was oscillating through rebound and compression strokes because the factory shocks and struts couldn't slow the suspension travel. Even the differential began to show signs of weakness, as the unchecked weight transfer unloaded the inside rear tire, allowing inside tire slip when exiting the corners.
Checking the speedometer at various places on the track confirmed that the car was running 5-10 mph faster with the Nittos. That's a major difference, folks. In fact, the extra speed caused us to overdrive the brakes.
Running 128 mph entering Turn 17 at the end of the back straightaway, I applied the brakes and the pedal slowly fell to the floor. Thankfully, my instructor didn't panic and neither did I, but we both agreed that the fun was over. The car was so much faster on the Steeda suspension and Nitto tires, the brakes just couldn't keep up. Brake cooling ducts would have helped, but realistically we should install Steeda's 14-inch front and 13-inch rear brake kits to sustain this level of performance on the racetrack without punishing the braking system.
Obviously our at-track installation proved enjoyable and enlightening. Track Guys provided a safe environment for us to push the '06 GT to its limits and beyond.
By performing one modification per track session, we were able to identify the benefit of each individual modification, with surprising results in some cases. Back on the street, the Steeda suspension, American Muscle wheels, and Nitto tires offer tremendous grip, and the Hawk Performance brakes bring the party to a reasonable level so that the authorities need not interfere. 5.0
Horse Sense: S197 Mustangs have become quite affordable as of late. With the soaring popularity of the '11-and-up Mustang, the price of '05-'09 examples has fallen well within reach of the average enthusiast. Even your poverty-stricken author was finally able to step into the S197 era by scooping up this '06 Mustang GT for the paltry sum of $12,900. As a daily driver, it has proven to be a dependable, fun, and relatively fuel-efficient vehicle with an average of 21.3 mpg in mixed driving.