Building a car is a series of milestones that fall in line until the builder is ultimately rewarded with a finished car. One such car-building milestone is paint, but another key moment is getting the car down on all fours and rolling about on its suspension. Our Camaro project Track Rat is no exception. A few months back we stitched a CA Chassisworks four-link arrangement under the back and now it's time to give the same TLC to the front. After having the '68 on a dolly for the last two years it'll be nice to see it rolling on terra firma.
For the front of the Camaro, we will be running a complete subframe from CA Chassisworks. To be precise, it will be their g-Machine subframe. This is a direct bolt-in deal, but that's where any similarity to the stock subframe assembly ends. The suspension itself was designed on a “clean sheet of paper,” not just a variation of OEM geometry. Using high-end Pro/Engineer software, the wizards at CA Chassisworks were able to create a current-technology, yet competitively priced, g-Machine front clip. And while the performance of this subframe will be similar to late-model Corvette-based systems, it doesn't force you to run flat-face, high-negative offset wheels. Prices range from just under $4,400 for their “value system” to $6,698 for their “ultimate pro-touring system.” But, there are myriad of various options available to tailor the subframe to both your needs and your wallet, so you might want to grab a notepad and hit their website at www.cachassisworks.com.
01. OK, so obviously the main player in the front subframe assembly is the subframe itself. The Chassisworks sub is larger and stronger than other tubular designs on the market. A lot of this is due to the massive 3x4-inch subframe structure at the critical chassis stiffness area from the front crossmember rearward through the firewall mounts. The design is completely enclosed, which adds strength, and each rail is assembled from four separate 12-gauge sheetmetal panels. The rail panels are CNC laser-cut and, once the contour bends have been made on the fully automated press, the panels are assembled using positioning features. They explained it as a three-dimension puzzle since the rail panels can only be fit together in the absolutely correct shape. Once in place, the four corner seams are welded with a continuous bead to completely bond the joint. The welds are so nice that even though they will sand them smooth (for $375), we recommend you spend that money on some open track days.
02. Installing the frame under the car was as straightforward as stuffing a stock frame under there. This is in large part due to the alignment holes, which duplicate the factory arrangement. Chassisworks also supplies a pair of CNC-machined alignment pins for even greater accuracy. Once both pins were in place, we simply tightened down the bolts through our aluminum body bushings (PN 6816). They do offer urethane bushings for those who want to cut down on transmitted vibration a bit, but we sort of like it.
03. According to Chassisworks, their lower A-arms are the strongest and most rigid pieces out there. The TIG-welded arms feature 1.25x0.156-inch wall steel tubing and 1x0.156-inch wall, multi-plane triangulated crossbraces. The CNC-machined weld eyes create a stable bushing housing that inserts into each arm tube and gradually tapers to match the outer tubing diameter. This eliminates fatigue points normally found in other “T”-style tubular bushing-housing joints. The geometry offsets the ball joint forward to improve static positive caster. It also places the shock very close to the spindle in a dropped position for better control. The lower pivot points are spread broadly apart, increasing performance while eliminating the need for secondary strut rods.
04. The lower arm was then secured to the subframe using the unique pivot-stud hardware. This specially designed Allen-drive, beveled-head pivot stud threads directly into the g-Machine crossmember. The fasteners feature a thread-free ¾-inch shank for maximum shear strength and have a broad bearing contact surface that reduces wear. There's also a shoulder on the bolt that ensures the correct amount of bearing preload. The arm is further secured using oval-point set screws. Also, you can see one of the rack mounts (red arrow) that uses Chassisworks' interlocking-slot-tab technology. Self-fixturing female slots in the frame are used to properly locate mounts, which employ corresponding male tabs. They are then fused together using a spray-arc welding process.
05. The upper arms may not look strong, but they are. Constructed from mandrel-bent 1x0.156-inch wall steel tubing, with 0.875x0.156-inch wall crossbraces, they are TIG-welded into a triangulated design that is strong and allows for plenty of shock clearance. With the aid of a fixture, the tubes are seated into recessed faces along the ball joint housing to create an interlocking fit. On the geometry side, the arm provides positive caster upon installation by offsetting the ball joint rearward. The pivot bearings are self-lubricated and require little maintenance thanks to minimal linear resistance and zero deflection. And if they do wear, the arms are easily rebuildable.
06. The use of CNC-machined billet steel allows Chassisworks to create A-arm mounts with specific areas of increased thickness for added strength. The fixed-axis pivot-pin design eliminates the possibility of shifting pivot shafts, has greater shear strength, and increases bending resistance. The increased rigidity of the design keeps the arm in place, making the car's handling predictable. You can see the one-piece clevis shock mounts that have an integrated gusset resulting in a great-looking, and more importantly, stronger mount that won't fail over time.
07. Chassisworks' g-Machine sculpted two-piece spindles feature a 2-inch-dropped ride height, but are taller than commonly used OEM spindles. This provides a lower center of gravity and quicker camber curve for improved cornering traction. Made from high-strength ductile iron (and cast for Chassisworks by a foundry with over 50 years of experience) the spindle yields an excellent strength-to-weight ratio. They also used finite element analysis (FEA) software to eliminate stress concentrations for even more durability under hard use. The spindle axles are machined from special high-strength alloy steel (tensile of 150,000 psi), then inserted into the machined upright forming a shrink-fit pressed assembly.
08. Most subframes utilize some sort of reworked OEM rack-and-pinion, but Chassisworks makes their own. This way they are able to dial-in the front suspension geometry by ensuring the correct hub-to-hub width. The rack is mounted forward of the axle centerline (i.e., front steer) for more oil pan clearance, and the rack can rotate to help eliminate a sharp universal-joint angle and offer a bit more exhaust clearance. The rack is held to the frame by using interlocking billet mounts that won't flex under hard cornering.
09. One of the option boxes we ticked was for Chassisworks' bumpsteer kit. This replaced the outer tie-rod with an adjustable billet steel sleeve and high-strength, Teflon-lined 4130 rod end. The tapered Grade 8 stud, along with a selection of shims, will let us vertically adjust the outer pivot point at the steering arms and correct any unwanted toe-in changes during suspension travel. With this kit there should be virtually zero bumpsteer in 6 inches of suspension travel.
10. Our subframe was one of the first offered with Chassisworks' new splined sway bar option. It's a 33-inch long, 1.25-inch OD gun-drilled bar, and we were pretty impressed with the bar and the hardware, especially the zinc-plated billet steel lever arms, which incorporates multiple endlink mounting holes. Teflon race, spherical-bearing endlink assemblies create deflection-free pivot points and help the bar react quicker and be more predictable. Endlink length is also adjustable to eliminate static preload.
11. The bar was mounted to the frame with billet aluminum bearing housings and 3⁄8-inch socket-head bolts. The low-friction bearings will allow the bar to pivot freely without introducing off-axis free play.
12. The billet aluminum hat and hub assembly helps to reduce weight and allow the individual components to be replaced if they become worn or damaged. The kit also included tapered Timken wheel bearings and ½x3-inch wheel studs.
13. To the Chassisworks' hats we secured the Wilwood 14-inch rotors using the supplied 12-point Grade 8 fasteners. The 1.25-inch thick rotors are directional-vaned, slotted, and finished in Wilwood's black e-coat. To create more surface area and maximize cooling, 36 individual “I”-shaped passages are cast internally into the rotor. The passages are also curved to increase airflow compared to standard straight vented rotor designs.
14. Once Track Rat is ready to hit the road, we'll install these double-adjustable VariShock QuickSet-2 coilovers. They feature sophisticated shock valving with all-new, American-made components. One knob sets bump (compression) while the other sets rebound (extension). Internally, they have Deflective Disk Valving to eliminate spring fatigue, and the piston rods are made from 5⁄8-inch centerless-ground, hard-chrome steel. The design of the lower ring doesn't require a lock nut; instead two ball locks that press into the grooves on the reservoir body lock it in place. Our starting point for testing will be the 2.5-inch ID, 9-inch-long 550-pound VariSprings.
15. The Chassisworks spindles utilize a radial-mount caliper, so the first step in getting the caliper in place was bolting the billet mount to the spindle.
16. Using the supplied shims, we got the Wilwood W6A radial-mount six-piston calipers centered on the rotors. We then used more shims to get the edge of the pad lined up with the edge of the rotor. Once lined up perfectly, we installed the BP20 pads and secured the bridge bolts.
17. With the actual subframe assembled we were able to check out some of the other features. One that really caught our attention was the super nice billet engine mounts. Most subframes we've seen use a two-part deal with an adapter plate bolted to the engine block, and typically a small-block mount to the frame. It works, but the Chassisworks' deal is nicer. For easier engine installation, the passenger-side mount on the frame used slightly oversized slots to account for minor chassis variances. Chassisworks' subframes also allow for the use of small- or big-block motor plates and mid plates in addition to standard side-mount brackets.