1997 Competition Associates SuperSport Yukon: Not-So-Gentle Giant

From the November 1997 issue Car and Driver.

Barry Brown is the kind of person who likes to do things himself. For example, when he discovered during the filming of his film Cloud Dancer that conventional film cameras could not handle the g-loads produced by the Pitts Special aerobatic aircraft they used, he designed a camera that could.

In Brown’s ramshackle Pacific Palisades home is a harpsichord he made himself, along with some homemade hi-fi audio components. Outside in the four-car garage are two “prehistoric” race cars—the Tasman Cooper-Climax and the Shelby King Cobra—on which Brown has done extensive restoration work.

So it was inevitable that after he bought a GMC Yukon to use as a general run and tow vehicle, the car’s various shortcomings would lead him to think of some upgrades. One thing led to another, and the surprising transformation led Brown to offer a limited number of what he called the SuperSport Yukon. (Or SuperSport Tahoe, or SuperSport Suburban, if you prefer.) That SuperSport prefix is ​​borrowed from the hot Chevys of yore.

Straight up, Brown thinks the Yukon needs more power. A K&N air filter working with Doug Thorley headers and a Borla cat-back exhaust system help open up the truck’s breather, and a Hypertech plug-in module (OBD II compatible) revises the spark advance curve, changes the transmission’s shift point and keeps the larger rear tire size for accuracy. speedometer.

The Hypertech thermostat opens at 160 degrees instead of the usual 180 for cooler running, and an undersized pulley from the same company reduces engine drag and cuts power steering assistance by 40 percent for better feel. Jacobs Electronics UltraCoil and low-resistance plug leads were installed to boost the ignition system, and that was how the engine worked until Brown decided to try a supercharger as well.

The car we tested wore a Paxton blower that produced 5 psi of stimulation, which, along with Brown’s other modifications, helped turn the Yukon from a roughly 10-second 0-to-60-mph sprint into a sub-seven-second performer. —no small feat for a 5100-pound sport. Its quarter-mile time improved from 17.4 seconds at 80 mph to 15.5 seconds at 89 mph, and our 30-to-50-mph and 50-to-70-mph pass tests were each shortened by about a second. Test results suggest an output of 400 horsepower and 400 lb.-ft.

On the road, that translates into a distinctly muscular feel, with strong acceleration available even at higher speeds. But straight-line grunt isn’t the SS Yukon’s deepest feature. It’s the way this big truck cuts through the mountain roads that is so impressive. It turns cleanly with minimal body roll, and it holds a line with more tenacity than you’d expect from a vehicle of this type. This is because the lower part of the car has been significantly improved. Up front, Bell Tech coilovers drop the vehicle two inches and raise its track by 0.5 inches. A stronger 1.25-inch anti-roll bar was installed, along with adjustable Koni shocks, Energy Suspension polyurethane bushings and pivots, one-inch shorter Bell Tech springs, and A-arms that were strengthened and trimmed by Precision Alignment to provide clearance for the larger tires. on full lock.

In the rear, Chisholm Enterprises provided custom leaf springs that lowered the ride height by four inches. A custom trailing link with a Heim extension from Chassis Engineering locates the rear axle, and a one-inch-diameter anti-roll bar from Bell Tech is added to tame the vehicle’s penchant for understeer. Like the front end, all bushings and pivots are polyurethane, and the shocks are Konis. Gracing the axles are 8.5-by-17-inch Antera 141 tires, with Yokohama AVS S/T tires: 265/60HR-17s up front and 275/60HR-17s out back.

To slow down all the action, Brown went to Baer Racing for 13.5-inch vented rotors with Alcon four-piston calipers using carbon fiber pads for the front wheel and 11-inch rotors for the rear wheel. Powered by Castrol Racing brake fluid through stainless steel hoses, this anchor is among the most expensive items in the mod ($6000), but it feels solid and powerful in use, and it cuts the distance it takes to stop from 70 mph to just 180 feet. (A Chevy Tahoe LS we tested went 45 feet farther.)

To put the final touches of luxury on the thoroughly revitalized chassis, Brown asked NASCAR supplier Sweet Manufacturing to build a blue-printed 12.0:1 steering box, and this mechanism puts the cherry on top of the reworked SS Yukon. There’s a precise on-center feel, immediate response to pressure on the rim and a linear increase as you put more lock into the steering wheel.

On the way back from our high desert test facility, we opted to cut through the mountains instead of taking the 14 Freeway to Los Angeles, and this decision may have provided better test data (albeit subjectively) than all the numbers recorded by our instruments.

To our surprise, the Yukon can be driven through hills like a big Mercedes or Bimmer. Because the steering is precise, the body roll is taut, and the tires do a good job of keeping the big vehicle on the pavement, we can maintain a pace that would scare most Yukon drivers out of their wits. Brown still talks about it every time we meet. And the extra engine power and big brakes are always there when you need them. Sure, the Yukon’s less-than-perfect structural creaks and squeals underscore the fact that you’re not in a big German limo, but the SuperSport’s road dynamics have more in common with those supersedans than you might think. maybe

That’s what Barry Brown wanted. If you want the same thing, you can go to the same person Brown consults or ask him to do the work you want. Brown has divided the SuperSport conversion into packages. The normally aspired upgrade cost is $3700. The supercharger package costs $9725 and includes most of the first package. The suspension kit, at $13,615, isn’t cheap, but it contains several custom-designed components and really changes the Yukon’s dynamic road feel. The cosmetic package, which includes a billet grille, stock vehicle exterior trim replacement, rosewood interior trim, CD player and high-zoot sound system, additional sound insulation and a rear wing, costs $3320.

The whole package, as we tested it, will set you back $27,000 installed. It sounds like a lot, but you end up with a powerful sport-ute that performs and handles like a large sports sedan. All for a total cost of around $55,000, if you shop wisely for your donor Yukon, Tahoe, or Suburban. Sounds okay to us.