Wheel, Tire, & Brake Upgrades Bolster The Fox v Ferrari Mustang

As part of this season of Horsepower Wars, one of our favorite Mustangs — a Fox coupe — got the nod to compete against exotic European machines to see if good old American aftermarket muscle can give a 36-year-old Mustang the edge. If you’ve been following the build of this Mustang LX coupe, you know things are progressing nicely. Now it’s time to add big brakes, custom wheels, and sticky tires to the Fox v Ferrari party.

The Fox is light, compact, simple, and blessed with an aftermarket that can turn a 1990 LX into something Ford’s engineers could never have imagined when this car was new. In the previous stages of Fox v Ferrari, LP Racing transformed the Bright Regatta Blue coupe with Maximum Motorsports full-length subframe connectors and a custom six-point-style cage, while Papini’s Garage added a Maximum Motorsports K-member, torque-arm rear suspension, Panhard bar, and more. Now, at Papini’s Garage, the hardware at each corner is catching up with the aforementioned upgrades.

There’s no shortage of ways to make a Fox Mustang faster, but this car isn’t being built just to make big power. It has to accelerate, turn, stop, and repeat those tasks on a road course. That puts a premium on brake capacity, tire grip, wheel fitment, and the ability to control all three as the pace increases.

Stopping Power

Up front, Papini’s installed a Wilwood Forged Narrow Superlite 6R big-brake kit (P/N: 140-9117; $2,701.33). The package uses six-piston calipers and 14-inch rotors, with the configuration selected for this build using black calipers and slotted rotors. The kit requires 18-inch wheels, which makes the wheel selection more than a styling decision. The rolling stock had to clear some serious hardware while providing the footprint this Mustang needs.

The front brakes are mounted on SN-95 front spindles with ABS tone rings, which is important as the project progresses. This Fox will eventually receive a Delta ABS system to better make use of all that braking power. For now, the tone rings establish another piece of the hardware needed to bring modern braking control to a chassis that originally relied on much, much simpler technology.

In back, Wilwood’s Forged Narrow Superlite 4R rear big-brake kit (P/N: 140-18151; $2,482.96) uses four-piston calipers and 12.88-inch slotted rotors. The kit is configured around Late Model Torino-style ends, making it a natural fit for the strengthened 8.8-inch that we’ll cover later.

Just as important, the system is designed as a complete package rather than a collection of mismatched components. The front and rear systems have to work together, especially on a car that will be pushed hard enough to expose any shortcomings in brake balance or pedal feel.

Future-Proof

Speaking of pedal feel, the factory arrangement was never going to be the final answer. Papini’s installed a Wilwood swing-mount brake pedal assembly (P/N: 340-16379; $225.80), which incorporates an adjustable balance bar and provisions for dual master cylinders. The pedal assembly allows the brake system to be tailored to the car rather than forcing the driver to live with whatever compromise the original Fox hardware delivered.

The dual-master-cylinder setup uses compact remote units with 7/8- and 3/4-inch bores, specified by Wilwood. That dual-master-cylinder arrangement gives the brake system another layer of adjustability, allowing front-to-rear brake bias to be managed mechanically through the balance bar.

The plumbing received the same attention to detail. Wilwood’s SN-95 Mustang front flexline kit (P/N: 220-6458; $102.21) handles the front connections, while additional Wilwood stainless-steel flexline (P/N: 220-8762; $34.08), caliper inlet fittings (P/N: 220-13125; $11.06), and chassis fittings (P/N: 220-6457; $13.02) round out the installation. The system is filled with VP Racing 622 Racing Brake Fluid (P/N: 2551; $26.99), giving the new hardware the fluid capacity and thermal capability expected of a serious track-oriented brake package.

Forged Fitment

To allow for the huge brakes, the Fox was blessed with a set of Forgeline GA3 three-piece wheels. Both ends use 18×9 wheels with a 24mm offset, 5×114.3 bolt pattern, and 71.56mm center bore. The wheels feature a polished rim, gunmetal powder-coated centers, and carbon-fiber center caps. Summit lug nuts (P/N: SUM-755565) fasten them in place.

These three-piece wheels feature a forged-aluminum construction that gives the Fox a serious wheel without necessitating the alteration of the classic visual appeal of the factory Fox sheet metal. More importantly, the 18×9 dimensions provide the room required for the Wilwood brakes while supporting a square tire setup.

Rather than putting a massive tire on the rear and leaving the front end comparatively starved for grip, the Fox wears 275/35-18 Hoosier TrackAttack Pro tires at all four corners. The TrackAttack Pro is an extreme-performance summer tire designed for high-performance use, and the 275-section width gives the Fox a substantial contact patch that fits within the confines of the factory wheel openings.

Progress Continues

Now the build comes together as a complete performance package, and there’s still more to come. A Delta ABS system will add motorsport-specific anti-lock capability to the equation, using wheel-speed information and adjustable slip control to help manage braking at the limit. It’s another piece of modern performance technology being adapted to an old-school Mustang without losing sight of the car’s streetable-but-exotic-beating mission.

For now, though, the Fox fitted with chassis, suspension, brakes, wheels, and tire upgrades is ready for the next major transformation. It’s still recognizable as a 1990 Mustang LX, but the hardware underneath is far more capable. Next up, we’ll head to RPG Racing Engines for the construction of the Predator-block-based Coyote that will provide the all-American power to out-muscle those exotics.

Horsepower Wars would like to thank its sponsors for making this show happen, including (in no particular order): Old World Industries/PEAK, VP Racing, COMP Cams, ARP, ATI Performance Products, JE Pistons, Boostline Connecting Rods, Total Seal, Cometic Gasket, Moroso, Hoosier Racing Tire, ECU Master USA, HP Turbo, Pure Drivetrain Solutions, SPE Motorsport, Moser Engineering, Delta ABS, Forgeline Motorsports, and Maximum Motorsports.