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Performance Front Subframe and Suspension Swap - Makeover!After A Couple Of False Starts, We Get Serious About Our '73 Camaro From the January, 2010 issue of Chevy High Performance By Christopher Campbell Photography by Christopher Campbell
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While the ultimate objective for Project F73 has been pretty clear in our minds since the beginning, we've only recently gotten serious about making solid progress and final decisions on the parts needed to get there. Sure, we got a little distracted by easy cosmetic upgrades such as our RS front clip swap and the temptation to spray on some shiny new paint, but we came to our senses and realized we were putting the cart before the horse. So, we're getting back to the meat of the project-the chassis and suspension package that's going to transform F73 from a mundane muscle car into a street car with real track cred. Since the day we dragged it back to the shop the plan was to take our basic 2nd-gen Camaro and turn it into a world class "driver's car" that would be able to carve through autocross cones or high-speed corners in open track events with authority while still not hiccuping during congested drives through heinous LA traffic or long road trips. Basically, we wanted an all-around muscle car that could easily stand its ground with modern equivalents performance wise, but not leave us longing for that refined OE-engineered and integrated feel. Thanks to a plethora of well engineered products on the market for F-bodies, almost any choice would certainly improve F73's handling well beyond factory. But, with so many varied packages and suspension theories out there, those options mostly led to lots of debate over the right package to meet our goals. That is until we spent some time talking with the former GM engineers over at Detroit Speed and took a ride in their '69 Camaro test car. Detroit Speed's subframes... Detroit Speed's subframes are standard in bare steel and unassembled. We opted to have ours powdercoated satin black and delivered with Detroit Speed's rack-and-pinion unit installed. Note the large aluminum spacers and bushings that locate the rack close to the engine cradle for proper steering geometry. Of note; each DSE subframe has a unique serial number on its data plate. With Detroit Speed's Stacy Tucker behind the wheel, the car proved to be incredibly aggressive on the track, but also very comfortable when cruising around-something we hadn't expected. Perhaps the best way to describe the difference is that the test car felt polished-not like an old Camaro with good parts bolted on, but like one that had seamless integration. The distinction is that DSE engineers didn't confine themselves to the Camaro's original architecture. Although the individual parts of the kit are important, Detroit Speed's hydroformed subframe is the platform that truly makes the difference in handling. While a cursory glance over the subframe shows that it's loosely based upon the stock GM equipment, there's actually a great deal of clean-sheet reengineering that went into the design to correct factory issues and dramatically increase torsional rigidity. That's particularly impressive considering that it remains a straightforward bolt-in part. We know what you're thinking: a subframe and full suspension swap sounds like a massive and intimidating project. We were under that impression ourselves, but discovered it's far easier than expected. Detroit Speed's front suspension package is designed with a garage builder in mind and goes together like a kit should: quick and easy. With the help of A&E Motorsports in Santa Fe Springs, California, we had the subframe and suspension swapped out in a day's time, but even in a home garage it's a weekend project at best. The beefy tubular lower control... The beefy tubular lower control arms are gusseted and crossbraced for strength, and revised geometry that includes additional positive caster and a lowered spring pocket. The nut should be roughly 21/4 inches from the end of the threads. That really sums up the other goal of F73; we want you to know that you can build this car too. Plus, since we hate project cars that get built and just disappear afterwards, we've got performance evaluation, testing, and lots of driving in mind for this long-term project that anyone who chooses to follow in our steps will know exactly what they're getting for their hard-earned cash. So you may have seen it in CHP 's pages before, but now that we've got our heads back in the right frame of mind, this is where Project F73 really begins. Quick Notes
What We Did
Swapped out the front subframe and suspension with DSE subframe and suspension components paired with Baer brakes. Bottom line
We finished nearly 50 percent of F73's planned chassis upgrades in a weekend and completely reinvented the Camaro's suspension geometry. Cost
$7,480 for the complete subframe and front suspension package with powdercoat and partial assembly option. $1,895 for the front Baer Pro-Plus system, $3,280 for the Rushforth wheels ($595, fronts; $895, rears; $75 each wheel for options), $400 for the BFG g-Force T/A KDW 2. Rather than the polyurethane... Rather than the polyurethane bushings found in many suspension kits, DSE opted for stiff Delrin bushings with steel housings and crush tubes that won't deflect under load.
While the DSE subframe and suspension swap could easily be done in a home garage, we sought out Bruce Monroe and his crew's extensive car building knowledge. A&E is a full-service shop that handles everything from drivetrain, to chassis, to full assembly, and since we're moving onto much more complicated work requiring some fabrication that's a little over our heads, we put F73 in the hands of the pros. Larry's Garage (the original name of the shop) has actually been in the same place for 45 years. Larry, the original owner, had worked for Howard Gilbert-the head designer for A.J Foyt-and two of his techs were also previously wrenching for A.J. One day young Bruce walked in and asked if they needed someone to change oil and do odd jobs. That led to 15 years of work and quality hands-on education. Several years later, Bruce ended up buying the facility and launched A&E Motorsports, all the while maintaining the original name. Since then, Bruce has handled everything from race cars and boats to turnkey street rods. To say we've been impressed by A&E's attention to detail and work ethic would be a severe understatement. These guys went above and beyond the call of duty on every aspect-almost like they were building F73 for themselves. That's the kind of pride in workmanship we love to see. If you're in SoCal, give 'em a call next time you need a shop that knows performance muscle cars.  Though this may change later...  Though this may change later when we dial the car in, we initially installed two shims per bolt on the upper control arms. While the arm is mild steel, the cross-shaft is stainless steel for strength and corrosion resistance.  The revised geometry of the...  The revised geometry of the upper control arms was aimed specifically at increasing camber gain versus stock and improving roll camber. Note the grease fittings; some say Delrin bushings don't need lubrication, but DSE recommends it.  The upper eyelet of the coilover...  The upper eyelet of the coilover mounts with Grade 8 hardware and a bushing. Make sure the bushing is properly oriented to center the coilover in the pocket.  Our coilovers are the standard...  Our coilovers are the standard aluminum body units that allow ride height adjustment and feature proprietary valving developed through track testing. They're not adjustable, but walk the line nicely between handling performance and ride quality. Three different standard springs rates are available: 475 in-lb for small-blocks, 525 in-lb for big-blocks, and 425 in-lb for LS engines.  Here's the big reason for...  Here's the big reason for all the suspension changes; the DSE subframe is designed around stock C6 Corvette spindles which helped engineers get the caster, camber, and toe curves the way they wanted-plus the added benefit of easily sourced performance brake kits and never needing to repack bearings during brake jobs.  DSE carries the full line...  DSE carries the full line of Baer Pro-Plus systems and recommended the 6P calipers with the 14-inch rotor upgrade since it's designed for outstanding performance on the track as well as the day-to-day stop-and-go. We also like that the calipers utilize off-the-shelf C5 and C6 Corvette pads.  Making the significantly dissimilar...  Making the significantly dissimilar spindle and rack communicate like they were designed for the same car is accomplished via Detroit Speed's unique modified steering knuckles that provide an excellent turning radius-something lacking in a few rack-and-pinion retrofits.  Rather than standard style...  Rather than standard style endlinks that sandwich the sway bar arm between bushings, DSE uses these aluminum pieces also sourced from C6 Vettes since they offer a much more precise transfer of motion. The ball joints are Moog equipment.  Here's one of the other huge...  Here's one of the other huge benefits of the DSE subframe; an integrated 11/4-inch splined sway bar. A properly installed three-piece sway bar eliminates the binding and flex inherent in standard one-piece style bars. Inside the retaining clamp is a Delrin bushing. Though DSE doesn't offer upgrades, serious racers could slide in different diameter bars with custom bushings to tune the suspension for various tracks and car weights.  The thick sway bar arms won't...  The thick sway bar arms won't have any unintended deflection. As such, the bar itself doesn't have to be as stiff to keep the car flat through a turn.  The DSE suspension package...  The DSE suspension package allows for up to a 10-inch-wide wheel without modification to the inner wheelwells, so we opted for killer 18x10 Livewire rollers from Rushforth Wheels. All wheels are custom built to your specifications and include a number of options ranging from 17- to 24-inch diameters with your choice of 7- to 15-inch widths. You can also personalize the finish with a full polish or opt between a powdercoated look with or without the perimeter hardware. After a lengthy conversation with Jason Rushforth himself, we went with the brushed-aluminum finish with polished wheel lips, which made for a rather stunning combination. Our rubber of choice included a set of performance oriented P275/35ZR18 g-Force T/A KDW 2's  Before removing the stock...  Before removing the stock subframe, we've got some measuring to do. With the car on jack stands, we dropped a plumb bob from the mounting bolt of the lower control arm.  Once we established the point,...  Once we established the point, we marked an X on the floor with a paint pen. Precision counts here since as little as 1/16 of an inch can throw the suspension geometry off.  Next, we dropped the plumb...  Next, we dropped the plumb bob from the mounting bolt of the rear leaf-spring pocket and marked it as well. Taking careful measurements, we were pleased and surprised to find that Project F73 was fairly straight with only 1/8 inch of variation from side to side.  After that, just a few zips...  After that, just a few zips of the air ratchet removed the four mounting bolts for the subframe.  Though they share a similar...  Though they share a similar shape, a nose-to-nose comparison shows some of the key improvements over the factory design that DSE incorporated into their subframe and suspension. Despite being significantly more rigid, the DSE-exclusive hydroformed framerails actually have a thinner O.D. The additional crossmember that mounts the rack and sway bar also serves to stiffen the front of the frame.  Overall, the rails are notably...  Overall, the rails are notably more consistent in form and lack the pinches and seams of the original. Note the multiple transmission crossmember mount options.  Forget rubber or urethane...  Forget rubber or urethane bushings, to eliminate the inevitable flexing between the subframe and body DSE uses solid- aluminum bushings and stainless steel bolts. Whether you use DSE equipment or not, this upgrade is a must for those serious about handling.  With a floor jack placed under...  With a floor jack placed under the main crossmember, the subframe actually balances quite well. With a buddy's help it's easy to position it and get the body mounts in place. Everything stays loose for now though since we've got more measuring to do.  Since the lower control arm...  Since the lower control arm mount location has moved, our original Xs weren't any help in centering the subframe so we dropped the plumb bob again to find our points.  Here you can see how far off...  Here you can see how far off the marks really are. These measurements are extra critical, so don't be afraid to take your time since side-to-side variations of 1/16 of an inch or less are considered acceptable.  Believe it or not, without...  Believe it or not, without much effort we were exactly 1/16 of an inch different from side to side. Who says there aren't any straight Camaros left out there?  With a little custom modification...  With a little custom modification by A&E Motorsports, we'll be hooking up our steering with a Flaming River steering shaft. This really needs to done before the engine is installed since accessibility will be very tight afterwards.  We've still got plenty of...  We've still got plenty of plumbing ahead of us for the brakes and rack-and-pinion, but we now essentially have the front suspension wrapped up. Next, we'll move on to the rear.
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