5.0 Mustang & Super FordsHow To Chassis Suspension
Ford Mustang Chassis Upgrade - FITness Plan
Strengthening a ’Stang’s understructure with Stifflers’ Fully Integrated Technology
The latest Mustangs bring a lot of greatness to our favorite ride. The modern 5.0-liter engines and Trinity powerplants and their six-speed transmissions are arguably the best drivetrains squeezed into a Mustang chassis. Likewise, the S197 chassis that houses all this goodness is worthy of props as well.
Veterans of the late-model Mustang scene surely remember the shake, rattle, and roll nuances of the beloved Fox ponies ('79-'93). Because of their unibody design, Foxes and their descendants—the SN-95s and New Edges—were prone to twisting, flexing, squeaking, and generally shaking themselves apart. This is especially true when engine mods increase torque and that grunt is put to the test on dragstrips, road courses, or the street.
At a minimum, adding subframe connectors to those cars was the best basic method of linking their front and rear halves. This creates as much of a true frame as possible and strengthens the flimsy factory chassis. The connectors work, for the most part. However, going beyond those basics typically involves installing rollbars or costly full cages.
Mustang's current undercarriage was developed in 2004 for the game-changing redesigned Ponies that debuted a year later. With the S197, Ford's engineers extended the 'Stang's front framerails, routing them along the entire bottom of the car within about 3 to 5 inches from the rear-lower control-arm pockets and fully welding the body to the chassis. The new structure presents as a true frame/cage of sorts that is leaps and bounds more stout than the earlier platforms.
As good as these cars are, nothing is perfect. While much better than Fox and SN-95's traditional unibody chassis, S197s are not completely void of flexibility. One man determined to rectify that is Brian Figg. He is the braintrust behind Innovative Performance Technologies of Plainfield, Indiana. As a former Indy Car race engineer, as well as a hard-core 'Stangbanger at heart, Brian understands such dynamics and has developed a way of making the good platform even better.
Innovative's Stifflers brand of chassis components is highlighted by a system it calls FIT, which stands for Fully Integrated Technology, a modular series of braces that are far more than just simple subframe connectors. FIT braces completely tie a 'Stang's subframes into its rocker panels, which Brian says is the real key to maximizing a Mustang's handling performance.
"You want a unibody to be as stiff as possible, as that's what's supporting a Mustang's suspension." Brian said. "Many enthusiasts make the mistake of higher rate springs, sturdier control arms, and such in an effort to stiffen their cars. What they don't understand is that these upgrades technically are ineffective if the chassis components themselves are not stiff or resistant to bending, twisting, and flexing, as Mustangs generally do under hard acceleration, braking, and cornering."
While FIT kits are available for all years of late-model Ponies, the following photos and captions detail our work with the setup that's designed for newer rides. Big-time thanks go to Ricardo Topete of GTR High Performance for reconnecting us with an old Mustang friend (see Horse Sense), who allowed us to set up his beautiful supercharged '06 Saleen with Stifflers subframe stiffeners (FIT-M03; $275) and lower chassis brace (LCB-M05; $99) in the course of about three hours.
Horse Sense: It's truly amazing how small the Mustang world is. Your tech editor first met Mike Luhm, owner of the '06 Saleen Mustang featured in this report, way back in 2000 at an NMRA/PSCA event in Phoenix, Arizona. Mike had a Fox 'Stang at that race and was fighting multiple problems. Your tech editor never saw Mike again after that event, and I wondered many times what happened to that kid (nicknamed "Hard Work" for his relentless effort) who had all those problems at Speedworld back in 2000. Thirteen years later, we reconnected, and Mike and his Mustang have come a long way.
While FIT kits are available for all years of late-model Ponies, the following photos and captions detail our work with the setup that's designed for newer rides
Big-time thanks go to Ricardo Topete of GTR High Performance for reconnecting us with an old Mustang friend
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We really appreciate having an opportunity to use Mike Luhm's beautiful '06 Saleen Mustang for this tech project. The 'Stang's supercharged Three-Valve engine boasts solid power at the feet (465). Mike isn't scared to exercise every one of those horses on the dragstrip, as well as on the high banks of Auto Club Speedway in Fontana, California, during open-track sessions. While Mike didn't have an opportunity to get on track before the deadline for this report, we asked him for insights on the difference the Stifflers FIT system makes on his 'Stang during his daily commutes, around SoCal, and weekend zips through twisties near his home.
"Once the Stifflers FIT pieces were installed, the increased rigidity in my car's chassis was immediately noticeable," Mike said. "With Foxes we say one of the first upgrades should be subframe connectors. However, by contrast, the first time I looked at my S197's chassis, I gave a sigh of relief and thought to myself: They finally did it right!
"That's true to an extent—Ford did a wonderful thing with the chassis. However, the improvement that comes with the FIT system truly is night-and-day different," he added. "Obviously, I'm relating impressions that are based on my seat time in the car since the installation and are by no means scientific. But seriously, the car seems to pull harder, and more importantly, straighter when accelerating, and it feels like it performs much better in the curves, too."