S197 Suspension Upgrade - Four On The Floor

Kenny Brown has a long history of Mustang chassis-building. Perhaps Kenny staked his claim in the '80s when the Saleen race team dominated the Escort Endurance Series championships. Those Mustangs were built by Kenny and proved unstoppable in the hands of Parnelli Jones, George Follmer, and, of course, Steve Saleen, among others. Kenny went on to build many Mustangs and Fords, including a signature line of Mustangs, and he was a player in the suspension-parts field for decades. Fame and the business grew for years, but as Kenny put it, he tried working himself to death and came down with a nasty series of pulmonary infections that derailed him for years. The good news is Kenny Brown has beat the bugs and is back in the Mustang chassis market.

Much newer is Stang-Aholics, a Terra Bella, California-based parts house. Proprietor Ryan Peter recently signed with Kenny Brown as one of his suspension dealers, and so the die was cast for us to follow along as Stang-Aholics installed the latest GT-4 Kenny Brown suspension and took it to the road racing track at Buttonwillow Raceway Park to see what they had wrought. What's more, Kenny Brown made the trip West for the track day so we'd have expert advice on dialing in the new S197 chassis kit.

That kit for the current Mustang is actually the fourth generation of Kenny's suspension (see sidebar), but like the three generations before it, the suspension hardware is designed to "fix the geometry," according to Kenny. Once the foundation of Kenny Brown suspension arms and chassis reinforcements is installed, the owner can then select springs, shock absorbers, and sway bars to suit his or her needs. As Kenny is quick to point out, his suspension system is modular, meaning the control arms and braces are a foundation the owner builds upon. As the owner gains familiarity and confidence, the same Kenny Brown suspension parts can be paired with increasingly aggressive spring, shock, and bar packages to take the car from an everyday commuter to track-only specialist.

To help customers sort their options, Brown offers the Street Sport kit. This is a street-friendly set of the GT-4 suspension, Eibach springs, H&R shocks, and sway bars that comes pre-set and ready to run once installed. It's the right option for first time suspension buyers and many casual open-track pilots who mainly daily drive their Mustangs. The other option is the Track Sport series. This group uses the same suspension bits, but with more aggressive springs and shocks. Hardcore drivers might accept this level on the street, but it's not recommended for daily drivers. It features single-adjustable shocks (one knob changes both compression and rebound) and the spring rate is in the 600–in-lb range. Typically Kenny sets up these customers with the recommended spring, plus one rate higher and one lower in case tuning helps.

If you're building anything more aggressive, say a dedicated open-track toy or a true competition car, Kenny prefers you call him so the two of you can arrive at a custom-tuned spring-shock-bar combination. But, as always, the suspension arms will be the same parts. Kenny notes that at this level he uses JRZ shocks built around those his son, Paul Brown, developed for his championship-winning World Challenge Boss 302S Mustang.

Kenny is candid about keeping his life and running his business, and not the other way around. To that end he has Heidts, a popular muscle-car and hot rod suspension maker, build his suspension parts. Kenny plans to build signature series, post-title Mustangs again. When those turnkey Kenny Brown cars arrive they'll--of course--use the same suspension components Stang-Aholics bolted onto its test car as shown in our photos. The install falls north of what the average bolt-on enthusiast can handle, but south of a complete re-engineering of the chassis. There are some holes to drill, tough nuts to chisel, and quality time with a welder, so it's a shop job for us civilians.

To hit the high points, the Street Sport kit uses weld-in subframe connectors, and new control arms on the front and rear suspension. The subframes come out of the box in two pieces and are trimmed to fit the chassis, tack-welded together in place, fully welded on the bench, and then the assemblies are welded to the chassis. The rear suspension is a pure bolt-in affair, replacing the Third-link above the differential (requires partially lowering the gas tank and accessing under the rear seat), plus the two lower control arms. A new Panhard bar is installed, along with relocated pickup brackets.

In front, the lower control arms are replaced and one of the attach point holes enlarged--there's some blacksmithing involved here as welded-on captive nuts must be chiseled off. The springs and shocks are replaced all around, of course. There is no rear sway bar--Kenny says he has the rear roll center so low that a rear bar is not needed in the Street Sport kit--and Ryan already had an adjustable front sway bar on his car, which was deemed correct for the application by Kenny, so it was left in place.

A few weeks after the install, we met with Stang-Aholics and Kenny Brown at Buttonwillow Raceway Park. This was our first look at the Kenny Brown Gen-IV parts in action and we were impressed. Ryan's car was purposely set up in street trim, with less spring and shock rate than optimum for hardcore track duty but with an easy street ride for daily driver duty. This is how most street cars are set up--and should be set up--and it's also the most forgiving for the neophyte track driver.

Nevertheless, the Kenny Brown augmented chassis proved friendly, with excellent stability, a surprisingly sharp turn-in, some understeer at mid-corner, and enthusiastic grip for hard acceleration on corner exit. There was good precision throughout the lap, and always a sense of confidence and predictability--traits rewarding to the beginner and accomplished track pilot alike.

The newer and less aggressive drivers on hand were well-served and happy with the street spring and shock settings, while the hard chargers only needed a smooth touch to extract good speed from the combination. The plush action of Ryan's car didn't surprise us, as Kenny Brown has traditionally gone for compliance over resistance in his suspension tuning. (The deleted rear sway bar is a good example).

All suspension tunes have a limit, and as is proper, the limit with Ryan's car was understeer, felt mainly in the high-speed sweepers. In the big open turns, the front tires gave up first and you had a choice of forcing the issue with the throttle--which would quickly over-heat the front tires--or show a little patience and maintain a lighter throttle, letting the big, heavy street car arc through. That said, the basic balance of the chassis was good, so fiddling with the spring/shock tune, or definitely a small rear swaybar, would trim the understeer out. In other words, the GT-4 suspension worked as advertised: smooth on the street, grippy to the spring/shock limit at the track, and ready to respond to more aggressive tuning should the owner opt for it. 5.0

Horse Sense: Yes, Kenny Brown the car builder is Paul Brown, father of the World Challenge champion. Interestingly, the Browns each forged their own way in motorsport with near total independence from the other, although they collaborate when possible.

Suspension Heritage

Kenny Brown can trace his current Mustang offerings through four levels of development. Here's how they break down:

• '87-'92 AGS Gen I (Saleen-R & Fox Mustang)--Revised front K-member geometry
• '93-'00 AGS Gen II (Fox Mustang, SN-95 Mustang)--Fixed-strut front geometry, TracKit plus rear geometry
• '01-'04 AGS Gen III (SN-95 Mustang)--AGS tubular K-member and control arms, AGS rear IRS module
• '08 AGS Gen-IV (S197 Mustang)--AGS tubular K-member and control arms, AGS Three-link live axle rear geometry

Parts Sheet