Classic C5 and C6 Corvettes just look fast sitting still . . . and for good reason. But as Aldan American has determined, there is room for handling improvement.
Without question, the Corvette has been the best-handling American performance car for over six decades. The Corvette has always been blessed with the most advanced handling and power features available at the time of production—all dedicated to delivering their lucky owners a car that was not only comfortable for touring around but able to be driven in a “spirited” manner on demand.
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The testbed for our upgrade was this very cool Corvette that had been previously outfitted with a double-adjustable coilover kit from Aldan American. Despite the owner having added some oversize tires and wheels and a few other goodies, the Corvette still sported the basic suspension parts (not including the Aldan coilovers of course), making it perfect for our handling upgrade.
The C5 (1997-2004) and C6 (2005-2013) Corvettes are regarded as some of the best ever produced. With great looks and impressive power they deliver lots of performance value. But even as great as they are, Corvettes were designed for a mass audience, meaning they not only had to deliver solid cornering g’s but also a suitable highway ride. At best, these suspensions are a compromise, leaving an avid enthusiast audience looking for even more performance.
Aldan American makes an array of different coilover-based suspension upgrades that can take your driving experience from dull to fun. This single-adjustable coilover kit includes everything you need to add amazing tunability to your Corvette, including springs, shocks, brackets, hardware, ride-height adjustment spanner wrench, and very clear instructions available online.
The engineers at Aldan American have been in the business of delivering tunable performance handling systems for many years. Their custom coilover suspensions can be installed on a wide assortment of American cars. Aldan American has a full complement of suspension parts, including coil springs and both single- and double-adjustable shocks with tunable internal valving.
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Starting with the front suspension, we released the sway bar link from the lower A-arm. This requires a box end wrench and Allen wrench.
Through their tunable shock coilover systems, the vehicle owner can customize the damping rate of the coilover for specific rebound or compression (in the case of double-adjustable coilovers) rates by simply turning a knob located on the shock body. In the case of their new C5-C6 Corvette system you can also adjust the ride height of the vehicle a full 2 inches by turning a billet aluminum collar that rides on the threaded shock body. As performance fans know, not only is a lowered vehicle great for looks it also lowers the car’s roll center—the conceptual pivot point on which the vehicle turns. Simply said, a lower roll center generally equates to better cornering ability.
Corvettes since 1963 have used transverse leaf springs to support the independent suspension. With the C5 and C6 Corvettes there are transverse leaf springs both in the front and rear. These will have to be removed in their entirety. That means carefully supporting the chassis and the front suspension then slowly releasing the tension in these springs. They will not be reused—the coilovers will now support the Corvette.
Our test vehicle for the installation of new Aldan American single-adjustable coilovers was an ’06 C6 Corvette. While the emblems flanking the car’s body announce Z06-equipped, this car actually only sports a few Z06 pieces (such as wheels, tires, brake ducting, and so on). The rest of the suspension is stock, base-level, Corvette stuff. Our test Corvette had recently received a set of Aldan American double-adjustable coilovers as part of a test case for Aldan’s engineering team.
The leaf springs are held in place on the vehicle with a series of bolts and plates. This photo demonstrates what the area will look like with the leaf and the plates removed. When dropping out the leaf springs, we suggest either enlist the help of a knowledgeable mechanic and/or utilize the information in a factory-approved assembly manual. Springs contain a lot of energy so be safe when performing this operation.
The move to a single-adjustable coilover is highly popular with many enthusiasts because it offers great tunability without the complexity inherent in the double-adjustable coilover system. Just think about it for a second; the single-adjustable has six points of compression adjustment in the front and 11 rebound settings in the rear. The double-adjustable kit has up to 66 possible adjustments (six compression and 11 rebound) per wheel. For that reason, the amount of time required to find your favorite hot performance handling setting or simply the right comfort level for that ride home takes significantly more testing. But for the performance fan looking for optimum adjustability, the double-adjustable coilovers can’t be beat.
While keeping the front suspension supported with a jack, release the bolts holding the shock/coilover in place from below. As mentioned earlier, this vehicle had already received a set of double-adjustable coilovers but the process would be the same if standard shocks were in place.
Adjusting a coilover setting is quite simple, regardless of the coilover flavor you select. To reach the adjustment knob, simply jack up a corner of the car, reach behind the wheel, and turn the knob one click at a time. While there you can use the Aldan American vehicle height adjustment wrench and drop or raise your vehicle, if desired. It should be noted that when lowering a vehicle, it is important to make sure that the tires or wheels do not come in contact with the fenderwells. If they do, we strongly advise lifting the vehicle up a few turns until the interference goes away.
With the pressure from the coilover/shock released and the front spindle still supported with a jack, we released the bolts holding the upper A-arm to the chassis. Note that there are four specialized washers that fit under the bolt heads. You’ll replace them when finished.
Follow along as we show you the basics of installing Aldan American’s single-adjustable coilover system. And by the way, we’ve overlooked one key point: affordability. The complete single-adjustable system, featuring all hardware, bracketing, ride height adjustment spanner wrench, and detailed instructions is only slightly more than the cost of a set of performance shock absorbers alone.
Pull the upper A-arm down and away from the chassis. This will allow you access to the bolt that holds the top of the coilover/shock to the chassis.
Fully adjustable coilovers featuring adjustable ride height and affordability? That’s a plenty impressive combination.
All that now holds the coilover/shock in the car is this single nut above this chassis tab. As you release this nut be ready to hold onto the coilover/shock since it will be disconnected from the chassis.Typical quality of the parts used by Aldan are things like this bushing that is designed to fit directly into the hole in the upper shock mount tab. When inserting the coilover, make sure all of the hardware is in the correct order as outlined in the instructions.Slip the new coilover in place, making sure that the adjustment knob is facing out so it can be accessed easily once in place.This photo notes not only the position of the adjustment knob on the coilover but also the fasteners that hold the coilover to the lower A-arm. There are not only two bolts but also two washers that fit under the bolts and on top of the T-bar. These washers allow for some movement of the coilover once in position.Compress the coilover with a jack under the spindle until the upper A-arm aligns with the original chassis boltholes. Use those special washers and original bolts to connect it to the original mounting location. Torque these bolts to factory spec in that factory assembly manual you are using—correct?As with all hardware, torque the bolts to the either the factory spec (for GM parts) or the specs as included in the Aldan American instructions. The coilover mounting bolts should be set to 35 lb-ft.For the rear suspension, different brackets are required to attach the coilover to the suspension. Aldan American supplies this unique bracket that allows you to use the original factory boltholes and avoids the need for any cutting or welding to complete the installation. As a starting position, we adjusted the compression setting to three—midway in the firmness scale.As with the front suspension, step one is disconnection of the sway bar link from the lower A-arm.After removing the rear leaf spring—carefully following the factory assembly manual—we moved to the upper A-arm and began removing the two bolts that attach the A-arm to the chassis. Note that the full vehicle weight is supported by our lift and each of the spindles is supported with another jackstand.With the A-arm unbolted and moved to the side, we unbolted the coilover/shock from the mounting boss. With those items out of the way, the mount now appears like this.Aldan American’s coilover mounting brackets feature left- and right-side coding. Mounting brackets (PN 91010) are used on the driver side suspension and PN 91011 fits to the passenger side mount.As with all of Aldan American’s coilover systems, the coil springs are coded for spring rate and installed height. Decoding this spring would be 6, for the installed height of the spring, and 550 for the spring rate in pounds of pressure to compress the spring 1 inch.This is a close-up of that cool little bracket that Aldan American’s engineers developed to locate the new coilover in the factory shock mount location.Reinsert the A-arm bolts in the same location from where they came. Make sure to torque them to the factory specs.The lower coilover mount fits in the original shock location using this specially designed Aldan American bracket that comes with the kit. Torque this bolt to 75 lb-ft. As a starting point, we set the compression knob adjustment in the middle by turning the knob counterclockwise until it stopped, then turned it six clicks in the clockwise direction.Setting the ride height of the Corvette was completed using the Aldan American ride-height adjustment spanner wrench. The wrench locates in the notches in the lower coil spring base that rides on the threaded shock body.Our enhanced Corvette now features incredible suspension versatility. With the Aldan American single-adjustable coilover kit we now have six points of compression ratio adjustment up front and 11-points of rebound adjustment in the rear. We also have the ability to lower the Corvette a full 2 inches from factory ride height when desired. Who says you can’t improve on Corvette perfection?
