S197 Suspension Upgrade - Four On The Floor
AGS 4.0 Club Sport Suspension Upgrade
From the December, 2012 issue of 5.0 Mustang & Super Fords
By Tom Wilson
Photography by Tom Wilson
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.
Ryan Peter and Kenny Brown...
Ryan Peter and Kenny Brown discuss the details of track operations. Kenny’s decades of Mustang track experience is invaluable in getting started in the demanding road racing disciple.
Kenny often ends up coaching...
Kenny often ends up coaching customers in track operations, and showed us his teaching technique at Buttonwillow. Here we see an ideal arrangement, with an experienced boss calling the shots and making notes, two crew members prepping the ride, and the driver free to concentrate on driving. The pickup and trailer relieve any worries about getting home in case of an on-track breakdown, even if Ryan's car is a daily driver.
Tire temperatures are the...
Tire temperatures are the basic gauge on how the chassis is working. Here, Kenny Brown PR ace Jeff Lacina does the honors.
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.
Ryan's S197 ran cool all day,...
Ryan's S197 ran cool all day, and we believe the TruFiber vented carbon hood helped. Out of habit, we ran the defroster for additional cooling, but it probably wasn't necessary. So far Ryan has not opened the hood's two ram air inlets, but the vents are definitely free-flowing.
A Shelby shifter certainly...
A Shelby shifter certainly helped crisp-up gear selection--a big help on track. There was only one 2-3 shift that required extra technique and patience, and that was out of the "on ramp" corner which twists the chassis like a licorice stick.
The Kenny Brown strut-tower...
The Kenny Brown strut-tower brace is an easy bolt-on installation. Underneath it, Ryan's engine is nearly stock, with the BBK cold-air inlet providing extra urge.
Ryan's rolling stock was well-equipped...
Ryan's rolling stock was well-equipped for track action and gave no trouble. The open-spoke TSW wheels were shod with Nitto NT555 tires, 275/40ZR-18 in front and 285/40ZR-18 in back. The six-piston Wilwood brakes did a commendable job when pushed hard on track, even with a street-friendly pad on board.
The differential-mounted Third-link...
The differential-mounted Third-link and the two lower control arms are the fundamentals of the Kenny Brown rear suspension. Well, these and the beefed-up Panhard bar. All use rod-end bearings instead of rubber bushings for increased precision, and they are adjustable. We heard the odd bonk from under Ryan's car, and the rod ends are sure to transmit some high-frequency sounds into the chassis, but generally the suspension has proven reasonably quiet in street use.
Here's the other big player...
Here's the other big player in the Kenny Brown rear suspension, the adjustable Panhard bar, again using rod ends. It also employs beefier struts and relocated brackets to lower the rear roll center.
Cut-to-fit units, the Kenny...
Cut-to-fit units, the Kenny Brown subframe connectors are delivered in two pieces. The straight section lays along the jacking rail; the truss piece is a little long and is trimmed to fit.
All geometry changes in the...
All geometry changes in the Kenny Brown suspension take place in the lower control arms; the rest is bracing. Here we see the control arms, lower chassis brace, and upper strut-tower brace, plus the H&R struts and Eibach lowering springs. Camber-correcting bolts and low-distortion swaybar bushings are also included.
Identity theft is a problem...
Identity theft is a problem with suspension parts, so Kenny Brown puts a serial number on all of the fabricated suspension pieces.
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.
It makes no difference if...
It makes no difference if you start at the front or rear of the car when installing the Kenny Brown suspension as long as you install the entire suspension. Stang-Aholics opted to begin at the rear, and here is the first step, removing the Third-link's upper mounting bolt, accessed under the rear seat in the passenger compartment.
It takes some fishing around...
It takes some fishing around to see the four mounting bolts holding the Third-link to the differential and chassis. Here, Ron Peter, Ryan's dad and major supporter (it comes with the job), guns off the fifth bolt, the one passing through the link and differential. Handling these bolts requires some muscle and hardware to gain access.
There's no way to get a camera...
There's no way to get a camera in where the Third-link lives, and in fact, the techs have a bit of a time seeing it themselves. Here the Kenny Brown link assembly is going it. It helps to have two folks, as one can pull down the gas tank a little while the other fishes the link into position.
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
Fitting the rear springs holds...
Fitting the rear springs holds no mysteries. Kenny Brown supplies an adjustable spring perch for the rather short Eibach rear coils, which gives some adjustability to the rear ride height, but count on about an inch of lowering.
Kenny Brown deletes the rear...
Kenny Brown deletes the rear sway bar at the Street Sport level, so the existing aftermarket bar was removed from Ryan's car. This is easy nut-and-bolt work.
Likewise, fitting the new...
Likewise, fitting the new H&R rear shocks is easy wrench work as well. With the car on a lift, you have the choice of either lowering the car or using a ladder to access the trunk and the upper shock nuts. The non-adjustable Street Sport shocks means they are ready to go out of the box.
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.
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
Kenny Brown lowers and straightens...
Kenny Brown lowers and straightens the rear lower control arms via new brackets. The bolt being tightening here requires a new hole drilled through the KB and stock brackets. This gives two bolts per bracket--the second bolt is hiding behind the wrench in this photo--so the bracket can't pivot.
Installing the new lower control...
Installing the new lower control arms is easy once the new brackets are in place. The arm’s length should be set to mimic the Ford arms that were removed; here Ron is double-checking that nothing moved during installation.
After removing the stock Panhard...
After removing the stock Panhard bar and its reinforcing strut, the beefier Kenny Brown strut is substituted in its place. Once this brace is fitted, new brackets are slipped into the stock brackets.
With the Kenny Brown Panhard...
With the Kenny Brown Panhard rod brackets in place, both sides are drilled, with one hole for a locating bolt. Note how the bracket has two holes for the Panhard bar, which provide some adjustability of the rear roll center.
With the two KB Panhard rod...
With the two KB Panhard rod brackets drilled and bolted to the stock brackets, the Panhard bar itself can finally be installed. Again, the bar should be the same length as the stock bar to begin with. Expect to have to push some to get the Panhard bar to line up with its mounting holes as the suspension swings sideways a bit at full droop when the stock bar is removed.
Step one in fitting the subframe...
Step one in fitting the subframe connectors is to temporarily clamp the straight bar to the jacking rail, then hold up the truss portion. The legs on the truss are purposely too long to accommodate chassis variations, so mark the truss for a snug fit to the jacking rail reinforcement, fire up the whiz wheel, and trim the truss to fit.
* Designed for use with Kenny Brown Front Lower Control Arms
|KB-29601||KB Two-Point Heavy-duty Strut Tower Brace||$109.00|
|KB-29405||KB Lower Chassis Brace||$109.00|
|KB-28029||KB Extreme Matrix Brace||$189.00|
|KB-28009||KB Jacking Rails||$79.00|
|Front Suspension Upgrades|
|KB-49721/31||KB AGS 4.0 Front Lower Control Arm Module||$749.00|
|KB-51656||Club Sport Coilover Shocks & Springs with Adjustable Ride Height||$1,780.00|
|KB-70655||Adjustable Front Sway Bar||$289.00|
|KB-81280||Camber Adjustment Bolts (2)||$34.95|
|Rear Suspension Upgrades|
|KB-28660||KB AGS 4.0 Adjustable Rear Lower Control Arms with Double Rod Ends||$299.00|
|KB-28665/75||KB Rear K-Link Upper Control Arm Module||$399.00|
|KB-28601||KB Rear Traction Anti-Squat Geometry Brackets||$135.00|
|KB-28620||KB AGS 4.0 Roll Center Bracket Kit (includes GT4 adjustable rear Panhard bar)||$498.00|
|Total—Recommended AGS 4.0 Club Sport Suspension Upgrades||$4,898.95|
|KB-49710||KB AGS Tubular K-Member*||$769.00|
Once trimmed, tack-weld the...
Once trimmed, tack-weld the truss to the jacking-rail reinforcement. Then remove the assembly and weld it solidly together on the bench. On the chassis prep where the truss and rail mate, buzz off the paint to bare metal, refit the subrame assembly, and weld it to the chassis.The KB subframe does ride over the fuel filter on the driver side; change the fuel filter now if there is any question about its condition.
Up front, remove the wheels,...
Up front, remove the wheels, tires and front struts, then take out the lower control arms. The tough part is persuading this lower control arm mounting bolt to break free--a stout wrench and cheater are typically required. Note that the bolt head is your only option as the nut--visible here--is welded to the K-member.
Once the bolts are out, the...
Once the bolts are out, the lower control arm will take a little leverage to pry free, thanks to the tight fit provided by the bushings. The open bolt hole just above the pry bar is the one requiring a little egging out, which we'll get to in a minute.
Here's the blacksmithing portion...
Here's the blacksmithing portion of the job--hammering, chiseling, and plain-old willing this weld nut on the K-member to come off. This is necessary because the KB control arm has a slight twist in it, and uses a through-bolt and nut instead of the stock weld nut.
Dry-fit the Kenny Brown lower...
Dry-fit the Kenny Brown lower control arm in order to judge how much of the front inner mounting bolt hole in the K-member must be relieved. Eyeballing the mismatch is close enough.
Luckily it won't take much...
Luckily it won't take much elongating of the hole to get the KB bolt through the K-member and control arm, 1/32 inch is typical. Use what you can for this job; a sharp rat-tail file and side-loading a drill both work.
The KB lower control arm is...
The KB lower control arm is lighter and less bulky than stock, and has a grease fitting on the lower ball joint for positive lubrication. Kenny Brown also has you install new Motorsport outer tie-rod ends; again, they have a Zerk fitting. The Kenny Brown installation seems a bit barbaric when it comes to elongating the control arm mounting hole, but it saves the expense and installation of a new K-member.
The last step in our install...
The last step in our install was fitting the lower chassis brace, which used to commonly be called a g-load brace. It is simple nut and bolt wor--the brace stiffens the K-member against side loads.