Most of the time when the topic of traction is dis- cussed the talk centers around the rear suspension. Yes, the 1979-2004 Mustang has been blessed with a factory four-link suspension system that could make it the best all-around drag racing style setup of any factory vehicle from any manufacturer. But the stock suspension in the back isn’t the only factor in going quickly from the starting line to the finish line—the front suspension is just as critical in this game of drag racing. Thankfully a unibody design has suspension components that bolt on to the chassis/body combo and in the case of the front suspension, that means the K- member cross-frame, A-arms, and McPherson-style strut system bolt-in and can be replaced easily.
Taking a step back, lets first go over a little history of the unibody chassis of the Mustang nameplate from 1979 through its demise in 2004. The Mustang line-up from 1979- 1993, which also includes the Capri and SVO models, uses a unibody nicknamed Fox-body and it was designed in 1978. The Fox-body chassis was freshened up for the 1994 model year and renamed the Fox-4 platform as Mustang took on a radically new look that year. It was kept in service for another decade until the 2004 model year. There are some subtle dif- ferences between the two unibody designs, mainly to address the wider body found on the ’94-’04 Mustang. The suspension components, however, swap back and forth just fine but do have some minor differences in the details. Through those years the car became strikingly popular not just for street performance but also for all-out drag racing and road racing efforts.
Replacement tubular K-member and A-arms became pop- ular sometime in the early-to-mid ’90s as the Pro 5.0 concept began to take off and eight-second times were becoming the norm. Today there are probably dozens of different K-mem- ber/A-arm setups on the market and one of the most recog- nizable and popular names in the game is UPR. Their involvement in NMRA-Keystone Drag Racing is huge as the UPR rig is at most NMRA events and the company backs several of the quickest players in many heads-up categories. We turned to them to get a Fox-body K-member kit that includes the K- member, A-arms, and coil-over conversion kit, made from lightweight chromoly material. We also added a set of the UPR adjustable caster/camber plates, Strange 10-way adjustable struts, UPR Extreme Bump Steer kit, UPR solid motor mounts, and finally we upgraded to UPR 1-inch shorter A-arms with adjustable heim-joint ends. With the parts in hand we ven- tured to Massachusetts where Dez Racing handled the installation.
Adding a tubular K-member and A-arms offers a few advantages with most notable being the weight savings. The total UPR package, with removal of the stock sway bar, tips the scales some 73 pounds lighter than the stock compo- nents. Most importantly the weight comes off the front-end, aiding in transferring the weight back to the rear tires. UPR’s Jeremy Martorella wanted to point out that all UPR front-end kits are made from materials that are purchased from the same company, which supplies tubing to Don Schumacher Racing and John Force Racing. Martorella said they use the same supplier because of the high quality of the material and wanted to make note that all fabrication and tig-welding is done in Florida and not outsourced overseas. And one of the final points Martorella wanted to stress is that the compo- nents come with a lifetime warranty.
UPR uses Eibach springs in most of its coil-over kits and offers several different spring rates—the extensive variety can help tailor your Mustang’s front-end for whatever challenge you target, from street/strip to drag racing and road racing. Additionally, other factors that come into play with the kit include better header clearance for those enthusiasts building custom headers. The car also becomes easier to work on because there is more room to fit tools, hands, and arms. For the turbo crowd out there—just think of the extra space afforded by a tubular K-member in order to fit the cross-over piping and routing the dump tube into the exhaust under the car.
Adjusting caster and camber allows the user to properly set up the front wheels. Camber is essentially the angle from the top of tire through the center of the wheel. If the top of the tire tilts inward as viewed from the front of the car, then it is con- sidered to have negative camber. Conversely if the top of the tire is tilting outward, then that is considered to be positive camber. The other side of the plates on top of the shock tower deals with caster. That is the degree of difference between an imaginary line drawn through the ball joint. If this line is tilted rearward, as viewed from side of the vehicle, then the caster is considered positive. If that line is tilted forward then the caster is negative. As a car moves forward a positive caster arrange- ment will have the wheels trying to center themselves against the movement and cause hard steering. “We recommend the factory settings for the caster and camber adjustments,” says Jeremy Martorella of UPR. The purpose for adding adjustable caster/camber plates is because when the car is lowered the geometry is thrown off. The UPR adjustable plates allow the alignment shop to bring those settings back to stock. “There are a couple of reasons we offer the Strange adjustable struts,” commented Martorella. “Strange offers a great price point that allows someone to add a quality adjustable strut at the same price as many other non-adjustable struts on the market.” On the performance side Martorella told us that an enthusiast can drive to the track with his or her family and have the struts set to stiff for a nice ride. Then once he gets there a simple turn of a knob loosens the strut for maximum weight-transfer on track. The struts can then be stiffened up for the ride home. He concluded, “It is an affordable street/strip strut that is simple to use.” The Eibach 14175 spring is the most popular choice at UPR as 85-percent of the coil-over conversion kits the compa- ny sells are destined for street use. “The 14175 gives a nice street ride but is still effective on the track,” inserts Martorella.
We opted for shorter set of A-arms with heim-joints rather than a pair of arms with bushings. This was done to allow us to move the wheels in for a sportier look and lower stance in race trim. We had to get a shorter spring with these A-arms because we want to try and fit a 17-inch wheel on this car for street use. The narrower stance from A-arms will bring the tire closer to the strut and the shorter spring will hopefully clear it. We haven’t bolted on the taller and wider wheels yet as Weld skinnies are on the car right now. Another optional item we added were solid motor mounts from UPR. The motor mounts in our test car were an OEM replacement and through the years they got a little worn out from the supercharged engine under the hood. We figured this was the right time to make the switch, especially since a stroker engine is waiting in the corner of the shop. As the car gets on the ground the owner can adjust the ride height and set the proper caster/camber as well as get better weight transfer for quicker times on track.
Dez Racing 508-336-6588 DezRacing.net
Strange Engineering 847-663-1701 StrangeEngineering.net
UPR Products 561-588-6630 UPRProducts.com