5.0 Mustang & Super FordsHow To Chassis Suspension
Racecraft Fox Mustang Suspension System - Off The Bumper
Racecraft shows us the way to quicker 60-foot times with its all-new suspension system for Fox 'Stangs
Horse Sense: Outlaw Mustangs with stock suspensions and true 10.5-inch tires were covering the quarter-mile in 9.4 seconds in 1999, with more cubic inches, ported high-port heads, automatic transmissions, and foggers full of nitrous. Today, NMRA's Real Street Mustangs cover the distance in nearly the same amount of time-with no more than 311 cubes, unported (except for stock) non-raised-port heads, stock camshafts, stick transmissions, 26x10-inch slicks, and a host of other variables that are quite limiting by comparison. Ya just gotta love the evolution of the game.
Wheels-up launches, low-10-second and, in a few cases, high-9-second passes are the name of the game in 5.0 Mustang & Super Fords Real Street-the entry-level, power-adder, heads-up category of the National Mustang Racers Association and the brainchild of our editor, Steve Turner.
Despite the presence of newer 'Stangs, such as the SN-95 and S197, in the class, the essence of Real Street has always been to keep things as mechanically simple as possible. That's similar to how things were back in the day, when the norm was flogging mostly stock, Fox Mustangs with five-speed trannys, a shot of nitrous, or a simple supercharger kit on the dragstrip. When asked about his vision for the class, Steve said, "I wanted to create a class that fit between Pure Street and EFI Renegade and more closely resembled the types of power-adder cars our readers build. I believed that limitations such as unported heads, short-tube headers, and five-speed transmissions would ultimately lead the aftermarket to develop racing products that would appeal to our readers building power-adder street cars."
The aftermarket offers racing-inspired products that can be applied to both dedicated Real Street efforts and daily driven street cars. Here at 5.0, new stuff for 'Stangs gets us hyped, and Racecraft's antiroll bar is revolutionary when it comes to parts that are accepted under the NMRA's and other sanctions' stock-style, rear-suspension rules. We couldn't pass up the opportunity to have a look at it during a recent trip to the Windy City.
Racecraft has been one of the premier builders of heads-up Mustangs for a long time. Mark Wilkinson, the company's co-owner and main man with the welding torch, is the fabricator who started the trend of cutting-edge Pro 5.0 cars with his development of Les Baer's '95 Mustang GT that attacked the gray area of rules more than 10 years ago. Many other NMRA and Fun Ford Weekend Pro, Outlaw, and Renegade 'Stangs have followed. The Real Street '05 Mustang of our friend Uncle Robin Lawrence is a Racecraft creation that's dear to us because it's the first S197 that was purchased and built for the sole purpose of competing in our class. Through Robin's series of articles in 2005 that chronicle the car's build, we watched Mark develop several brand-new, bolt-on suspension parts for '05 and '06 Mustangs, which is what Real Street is all about.
In addition to the race Mustangs it's famous for building, Racecraft is also known for K-members, A-arms, spindles, and other parts that help bring perfect front-suspension geometry to '79-'06 'Stangs. While the market is well stocked with Mustang suspension pieces [check out our Suspension Guide in the Aug. '06 issue, p. 136], Mark and Racecraft co-owner, Matt JaBaay, have recently expanded their product line to include a complete, rules-compliant, rear-suspension system for Fox cars. The line includes chrome-moly upper and lower control arms, rod-ends and spherical bearings throughout, and the aforementioned removable antiroll bar, which is an industry first for late-model Mustangs of any year.
Bruce Hemminger's '86 coupe is probably the only 'Stang in the game that has competed and won in both a true 10.5-tire category in FFW's Street Outlaw in 1999 and in NMRA's Real Street, as it finished number two in points in 2002. Real Street is the car's current home, and despite Bruce's commitment to drive JPC's nitrous-injected coupe in 2006, he's been testing and sorting out engine and chassis issues in his trusty '86 on a regular basis. He hopes to have it back in competition at some point during the '06 season with a hired gun at the controls.
Taming the car's wild, wheels-up launches and lowering its 60-foot e.t.'s have been Bruce's main areas of concern, so he was more than happy to offer us use of his ride to install and test Racecraft's front and rear suspension systems. The car has been sitting on an assortment of heavy, mismatched front and rear suspension parts for a long time. By adding Racecraft's lighter, chrome-moly tubing in the front and the rear, different springs, a new steering setup and frontend geometry, and the new antiroll bar, we wanted to see what, if any, differences the changes would make in the coupe's launch and overall handling performance on the dragstrip.
Keep reading for details on the parts and the results of our dragstrip testing.
Mark Wilkinson, Matt JaBaay, and Nate Wallace hoist Racecraft's Fox Mustang front suspension into place under Bruce Hemminger's high-flying '86 Real Street coupe. Racecraft completely revamped the car's front and rear suspension setup, for better launch (lower wheelstands) and 60-foot performance, as well as high-speed stability.
Old and plenty worn out, this frontend has been on Bruce's coupe since its Street Outlaw days, and in some cases, beyond that. Note the modified factory spindles for mounting both the V-8 struts and drag-brake brackets, and the upper spring perch on the K-member. This car was done long before the days of purpose-built race cars.
Mark and Nate haul the old frontend to the shop's scale. This mild-steel apparatus weighs 75 pounds.
We put Racecraft's chrome-moly front suspension on the scale immediately after weighing the original pieces. It included the K-member (PN 3273500015PR; $479), 12-inch-long A-arms (PN 3212TA00; $299), spindles (PN 300102; $495), bumpsteer kit (PN 333202; $109), and Racecraft's manual Pinto steering rack assembly (PN 333100; $189) with billet rack clamp (PN 333107; $24). To nobody's surprise, the new frontend registers a svelte-by comparison-58 pounds. The K-member used for this project has more than 24 inches of overall clearance, including a 1.5-inch drop for the rack, which allows plenty of room for big-tube headers and painless, in-car removal of the oil pan when necessary. The lightweight tubular A-arms are set up for coilovers and feature adjustable rod ends and standard ball joints. At 12 inches, Racecraft's A-arms are 1 inch shorter than stock, which is the typical length for drag-race applications.
Nate sets up Racecraft's coilover kit (PN 333015; $269) with Hypercoil 150-pound front springs, replacing the 120-pounders that were originally installed on Bruce's coupe. Mark says that by using a less-compressed front spring, Bruce's trademark and e.t.-killing moonshot launches should be a thing of the past.
We really dig this part. Racecraft's front spindles, which are patent pending, include a 2-inch drop and are designed so that many of the popular, aftermarket drag-brake systems can be bolted on without modifications. With their 2-inch drop, Racecraft spindles eliminate the bumpsteer problem that's common to drag-race Foxes and return two inches of spring/strut travel to the front-end on a lowered race 'Stang.
On the top is Racecraft's chrome-moly steering shaft (PN 333102; $249, or $189 with unsealed U-joint) with the shaft we removed from Bruce's coupe. While the two shafts have the same diameter, the Racecraft shaft allows for more header clearance thanks to its smaller-size U-joints. The orange boots around the U-joints on the Racecraft shaft help keep the knuckles lubricated and protect them from dirt and debris.
Matt installs one of the new caster/camber plates (PN 340001; $189) on the top of the strut tower. Racecraft's stout plate setup rounds out the front-suspension package.
Hollow, 51/48-inch chrome-moly through-bolts such as the one shown in this photo are optional ($29.95/pair) for installing Racecraft's A-arms, and they contribute to the overall weight savings of the complete suspension system.
Here's a look at the completely new, lighter front suspension on Bruce's Real Street coupe. "With this frontend system, we just tried to correct all of the things that have been wrong with Mustang front suspensions for a long time," says Mark. This 100-percent bolt-on system is available from Racecraft as a complete package, but because of the available options we suggest you contact Racecraft to discuss a setup that's best suited to your 'Stang.
We couldn't believe what we were seeing when we inspected this rear upper-control arm. The old arm has nearly broken through, which tells us that Bruce's 'Stang was probably only a few more launches away from disaster had this crack not been caught.
On the right are Racecraft's chrome-moly, rear upper control arms ($249). These pieces feature chrome-moly rod-ends and double adjustability for achieving spot-on pinion angle. Mark suggests starting with 2 degrees of negative pinion angle with the upper arms, then testing and making negative or positive adjustments as necessary.The lightweight lower control arms on the left ($299) also include adjustable, chrome-moly rod-ends and feature Racecraft's roller bushings, which help eliminate bind in the rear suspension when a Mustang launches.
This all-new rear suspension system looks great installed. As with the front suspension, the rear components can all be purchased as a package.
Bruce's Real Street coupe sits nearly as low as-and now has a chassis that performs like-a Super Street Outlaw Mustang, thanks to Racecraft's bolt-on Fox-Mustang suspension systems.
Tale of the Timeslip
After we installed the front and rear suspension pieces and aligned the coupe's frontend at Van Drunen Ford where Bruce is the sales manager, the revamped 'Stang was put through its paces in a test session at Byron Dragway.
Bruce launched at 4,000 rpm with the antiroll bar set at "neutral," or no preload, for each of the three test laps he made. The coupe dug in and drove out straight and smooth, with a much lower, gradual wheelstand, as opposed to the near-vertical e.t. killers that were the norm with the old suspension. The addition of timing and "two-clicks" on the front struts to tighten them were the only adjustments for the day. We saw gradual 60-foot improvements in each pass, from a 1.36 off the trailer, a 1.35 on the second hit (with timing added, equal to previous best-ever), to a new best-ever short time of 1.337 on the final run, with timing added and struts tightened. These are the incremental times from the last hit.
660-foot: 6.326 (106.91 mph)
(133.05 mph, a 3-mph gain)
The new suspension appears to have helped solve the issues that contributed to the coupe's inconsistency from the starting line to the 330-foot mark. "After reviewing my Auto Meter Dual Channel playback tach's data logs after each run, I saw that the new suspension made a big improvement in keeping the tires planted through the front half," Bruce says. "The car also feels a lot tighter and more stable down track. The data also tells me that I've got room to add a lot more timing, so I've got absolutely no doubt that this car can go 60 feet in the 1.29 range when we really get everything dialed in."
Industry First: Removable Rear Antiroll Bar
Mark Wilkinson and Matt JaBaay of Racecraft are on to something with the new rear antiroll bar, which features billet-steel arms, spherical bearings, Zinc coating to prevent rust, and a patent-pending design that allows the bar to be removed from under the car for cleaning and greasing.
This new suspension piece by Racecraft is made completely in-house, as is everything else we saw during our visit. It was developed on a "live" Mustang, so installation is hassle-free for any experienced welder/chassis fabricator, and fitment is great.
These are the remains of the original antiroll bar that was on Bruce's coupe, and they're definitely ready for the scrap heap. Mark cut this baby out with a plasma cutter, as that was the only way to remove it.
Eighth-inch, square plates are welded to both framerails as replacements for the frame sections that were extricated with the original antiroll bar. The plates serve as anchoring pads for the antiroll bar's billet-steel bearing housings, and are only necessary if you're replacing another antiroll bar that's been removed from the car.
This is Racecraft's new antiroll bar assembly for '79-'93 Mustangs. The system includes everything shown in this photo: chrome-moly bar, spherical bearings and housings, billet-steel arms, chrome-moly rod-ends, and Grade 8 hardware. A good chassis fabricator can install it in about two hours. A part number has not yet been established for this new suspension technology. It is available now and retails for $499.
Racecraft's antiroll bar seats inside these spherical bearings.
Bearing housings for both ends of the assembly are welded onto 11/48-inch plates that are attached to the framerails during installation. The spherical bearings seat inside each housing and allow the antiroll bar to float under the severe stress of hard launches, but they maintain rearend squareness and keep the tires planted.
Each end of the antiroll bar is placed inside the spherical bearings on each side of the frame...
...and a billet-steel cap is then installed over the passenger-side bearing and secured with Allen-head bolts.
This is one of two adjustable links that are the most pivotal components in an antiroll-bar system. The adjustable links are used to add preload to either side of the race car, depending on which direction the car is pulling at the hit of the throttle. Starting with the links in a neutral state, if the car pulls to the right, the passenger-side link is lengthened to add preload. If the car pulls to the left, the link on the driver side needs to be extended.