A factor that can make or break any Pontiac street machine's first impression is stance--how it sits on its suspension in relation to the road. Until recently, stance was a one-time, hit-or-miss proposition based on careful spring selection. But thanks to the arrival of adjustable-height air-ride suspension systems, radical changes in stance can be made in a matter of seconds.
In this story, we bring you news of an exciting new Air Ride Technologies air suspension system designed specifically for owners of '64-'67 GM A-body vehicles--yep, that means our beloved GTO's, Tempests, and LeMans--though the kit fits Chevy, Buick, and Oldsmobile A-bodies as well. This new system replaces traditional coil springs with adjustable air bladders that are filled by an onboard electric compressor, which is capable of altering ride height an amazing 4 inches, front to rear, side to side, or all around. In a realm where a 1/2-inch change can have a dramatic impact on overall vehicle attitude, this much adjustability is truly revolutionary.
The front coil spring pockets...
The front coil spring pockets must be enlarged because GM originally designed them with 5-inch-diameter coil springs in mind. The replacement ShockWave units are 61/2 inches in diameter. Here is the driver-side, stock coil spring pocket before full modification. Eagle-eyed readers will note some trimming has begun.
To show off the new system, we enlisted the help of Mark Vogt's '67 Tempest convertible frame. Yes, it's a little rough on the eyes at this stage, but rest assured, Vogt, who is chief operations officer for Classic Industries, has big plans for it. The frame will soon rest beneath a trick '67 GTO clone we hope to feature in HPP as soon as it's unveiled. Until then, you can check out progress on the drop-dead drop-top at Vogt's Web site, www.backyardcars.com.
Need one of these air suspensions for your Poncho? They're in stock and ready for shipment at Air Ride Technologies and through Original Parts Group (Classic Industries' corporate cousin). Check out the photos for installation details.
What about front suspension alignment? Glad you asked. Whenever vehicle ride height is altered from factory settings, front caster, camber, and toe adjustments must be made to reestablish correct steering geometry and minimize tire wear. So, after installing the air suspension system on his completed GTO clone, Vogt will hightail it to a competent four-wheel alignment shop. There he will sit in the car with a full tank of gas and play with inflation pressure until the car sits at the attitude he digs best and where he plans to do most of his driving (probably 3 inches lower than stock).
The Goat is then rolled onto the alignment rack where a factory-spec alignment will be administered. The well engineered Air Ride Technologies StrongArm tubular front control arms will ensure the factory settings work despite the lowered stance. Vogt will enter the air-pressure preset information into the RidePROe programmer so the onboard compressor automatically inflates the bladders to the correct height every time he starts the car. As for those times he wants to slam the car even further or raise the car and show off a little, ideal caster and camber are lost. But with limited use, tire wear shouldn't be a problem in those temporary modes.
AIR VERSUS METAL
Although adjustable ride-height air-suspension systems have been given a black eye by certain all-show, no-go installations in the low rider, sport compact, and sport truck world, Air Ride Technologies systems are different. That's because each kit is specifically tailored to its application and engineered to maintain or improve on factory suspension geometry. The StrongArm control arms, shock absorbers, and airsprings are designed to work as a team to deliver the best combination of ride quality and handling capability with a stylish lowered stance.
Frame surgery is no place...
Frame surgery is no place for haphazard work and second guessing. Mark Vogt improvised this simple mock-up fixture (on left) using a 2-foot length of 1/2-inch threaded rod, matching nuts, washers, and a 7-inch circular tin disc. Hidden below the disc is a 1-inch-long steel sleeve welded to the end of the rod at a 90-degree horizontal angle that accepts the lower shock-absorber through bolt.
The top end of the fixture...
The top end of the fixture is double-nutted into the frame's stock upper shock absorber mounting hole. The bottom end bolts to the lower shock absorber mount of the kit's trick StrongArm lower control arm.
With the temporary fixture...
With the temporary fixture bolted in position, the exact space to be occupied by the airspring can be determined. The goal is to remove any metal that prevents the tin disc from fully entering the spring seat. An ink pen marks the metal to be trimmed. (If you don't feel like making up a fixture like this, you can just use the ShockWave unit itself to determine where the frame interference is.)
Air Ride Technologies says its kits are at their best when the airsprings are inflated to produce a vehicle ride height 3 inches lower than stock. In fact, this is the target zone where their systems generally deliver peak handling prowess thanks to a reduced center of gravity. Going lower looks great when the car is at rest but it risks bottoming the bumpstops, not to mention potential oil pan and exhaust system trauma when the wheels are turning.
For all you members of the Herb Adams fan club out there who are skeptical that an airspring can equal a well chosen coil spring for road racing or severe handling, know this: While steel coil springs are rated by the amount of weight required to compress them 1 inch, airbags are rated by the maximum amount of weight they can carry while inflated to 100 psi. This load rating is generally determined by the diameter of the airspring.
In this story, 6-inch, 2,200-pound bladders are used up front and 5-inch 1,500-pound units are used at the rear. But here is the critical difference between air and metal. Once you've installed those killer, 400-pound coil springs under your GTO, you're stuck with them. With airbags, you have nearly unlimited air-pressure adjustability to tune the ride quality, chassis preload, and height--and not just front and back, but also corner to corner and side to side. Jounce and rebound characteristics are tuned using the kit's QA1 adjustable shock absorbers (optional at the rear). Front and rear stabilizer-bar selection is not affected by whether compressed air or coiled-steel wire supports the car, so you're free to select even the beefiest bars to control body roll in the esses.