Ask any “Old Salt” racer and you’ll be told that the seemingly endless expanse of natural salt to the east of the Wendover, Nevada, city limits is a little on the strange side. It’s a place where the mountains don’t even touch the ground. They just hang out there above the horizon. And the people? During Speed Week, at least, you know everybody in town. Virtually every vehicle that passes down Main Street is a dualie with the appropriate hauler hanging oft the back porch. Everybody in the temporarily doubled population is there to play on the salt, and every conversation is about cars, engines, or their related problems. You are immersed for a week in the talk of guys who know what to do with a rearend gear that is numbered in the high twos. Speed Week at Bonneville has a weirdness all its own—and it seems to fit one particular team’s record attempt.
While most sane folks were sitting at home watching reruns of this country’s 20-year-old moon landing in July, one of the guys who made that historical event possible, Don Gothard, had the top guns from GMC Truck’s Pegasus (Advanced Vehicle Engineering) Group on the salt with an S-15 pickup. Gothard was an important part of the team responsible for the control systems in both the command module and the Lunar Insert Module (LIM) when Aldrin and Armstrong set their vehicle down on a surface about as desolate and imposing as the salt. In terms of challenges, Gothard had chosen another one that sounded about as tough as landing on the moon.
This new project, code-named Pegasus 3, was intended to garner a world record in two classes for the GMC Truck folks. What had started as a three-way conversation at the Los Angeles Car Show in January 1988 became a reality on the salt by July 1989. That didn’t make it any less unreal. Nobody, but nobody, thinks in terms of a truck when you’re talking world top-speed records.
Even though Tim Richmond had blown oft a Porsche at the Ohio proving grounds with a NASCAR Chevrolet, that doesn’t mean that a pickup truck should have been after another Porsche record. That German sports car in Ohio had been driven by one of the best, the late Al Holbert, whose high-speed portfolio included the world records for E Production vehicles in the flying mile and the flying kilometer.
It may be a bit of a stretch to imagine a GMC S-15 mini-truck in the same class as a Porsche 928, but an investigation into FIA, lMSA, and SCTA weights and wheelbases shows that the two are, in fact, very compatible. We wouldn’t recommend the two on the same road course, but on the salt they do stand fairly equal. Since the U.S. National record for pickups already fell conveniently close to the international records, the GMC folks were shooting specifically for the Class E stuff, and they’d take whatever incidental fallout might occur.
Once the goals were clear, all that was left was to build the gun meant to shoot holes in the old records. What GMC took to the salt (besides a hefty checkbook) was definitely a quick-draw special that would tame the Old West in short order.
From the outside, and strictly by the rules, the truck needed to appear stock. The attached body fairings, for example, were available at any GMC dealer just by checking off the proper box on the option list. Most of the areas, in fact, that some teams use to, shall we say, gain an edge, were ignored. (For international records the headlights are allowed covers, but for national records during Speed Week those covers are removed.) None of the ‘glass was flush mounted, the roofline didn’t display the common “ducktail” treatment, the windshield wasn’t laid back, and the hood wouldn’t “accidentally” develop a depression at speed. In short, this is not a NASCAR-style “stock” body.
Conversely, the powerplant is exactly that. The rules call for an engine that looks like the stock unit and is essentially similar. That’s almost NASCAR talk for “build it any way you like as long as it looks legal.” The Katech-built 5.OL V6 engine that powered the Pegasus S-i 5 was based on the 90-degree Bow-Tie, cast-iron cylinder block normally sold as a 4.3L production unit. Instead of the even-firing crankshaft found in the stock unit, the race motors were equipped with odd-firing Moldex cranks carrying Oliver rods and Diamond pistons. For superior breathing, Brodix aluminum heads were used.
The valvetrain was built on a Competition Cams steel-billet roller and Iskenderian lifters with a Katech rev kit. Falconer provided the needle bearing rockers that depress titanium valves. The oil tank in the cargo bed is fed by a Weaver dry sump pump. Kinsler fuel injection is fed by an AC/Rochester fuel pump, regulator, and injector nozzles, while the fire comes, naturally, from a Delco capacitive discharge unit.
A Delco Gen II electronic control module monitors throttle position, intake air temperature, coolant temperature, crankshaft position, and engine speed. From that information, the Gen II determines ignition timing and fuel-injector nozzle timing. Although Gale Banks Engineering took care of the final preparation and on-the-salt care and feeding of the truck, it does not employ turbochargers. Despite that, the truck does employ intercoolers.
All intake air is precooled by a super high-tech system. Defined as an “intake- charge cooling system with a finite usable lifetime,” it is an excellent example of plain old American hot rodding. Since a reduction in inlet air temperature correspondingly results in added power, these intercoolers act just like units normally found on turbocharged engines. The intake-air radiators were plumbed to a full ice chest in the truck’s cargo bed for each run. When a run was completed, the ice was replenished during the turn-around procedure.
The 5.0L engines used during the FIA runs were rated at 523 hp at 6800 rpm and credited with delivering 414 lbs.-ft. of torque at 6400 rpm. The engines to be brought to Speed Week are 4.26L units that are expected to provide 470 hp at 7800 rpm and 355 lbs.-ft. at 7000 rpm. The smaller engines use essentially the same parts lineup as their bigger cousins.
The drivetrain behind either engine starts with a Tilton triple-disc clutch and a Weisman quick-change, 5-speed tranny. A carbon-fiber driveshaft transmits the power to a 9-inch full-floating rear constructed with Strange Engineering parts. The rearend ratios are relatively high at 3.10:1 and 3.25:1. The rear brakes are discs with slotted rotors and JFZ four-piston calipers. No front brakes are available to driver Don Stringfellow.
But Stringfellow wasn’t looking for more brake. Already a member of the 200 Mile Per Hour Club, Don had high hopes of repeating that speed with the black and white truck. He very nearly succeeded during the FIA runs.
On the first set of official runs he averaged 187.677 for his two-way effort. While this effort was a new record right out of the box, anybody who has ever survived the rigors of a development program knows that the next two steps are usually backwards. But not for this team.
The second day’s runs set another new timing mark with an average of 192.545 mph for the flying mile and 311.975 kph (193.861 mph) in the flying kilometer. Not a bad warm-up for Thursday’s announced record attempt.
Thursday morning brought the press to watch, and Stringfellow uncovered a few secrets he hadn’t found the first two days. His first run from west to east was better than any he had made in that direction at 189.304 mph, and the return at 197.897 mph yielded another new record. After one false start, another west-to-east pass at 191.683 mph was to be the last for the session as the weather closed in and shut down the course.
If Stringfellow was disappointed with the fact that the truck hadn’t quite carried him over the 200 mark, it was the only unattained goal in the entire effort. The GMC Pegasus S-15 established a new record average speed of 194.770 mph in the mile and 313.555 kph in the kilometer, and therefore captured both the Category A (Group 2, Class 9) and Category E (Group 2, Class 9) standards. GMC Truck had its records, Gale Banks wrapped up another successful trip to the salt, and Don Stringfellow brought back a whole truck that would see duty again shortly when Speed Week rolled around.
The interior of the truck, by the rules, must resemble a stock pickup. But don’t look for Recaro seats, a roll cage, or all that instrumentation at your dealer’s showroom.
While the GMC 8-15 salt scorcher looks like something you could see on the street, it is the fastest mini-truck In the world.
The Katech-built V6 engines-in either the 5.0L or 4.26L versions— look exactly the same. The change in displacement comes from a stroke increase, Kinsler injection, Brodix aluminum heads, and a Competition Cams roller cam help make the power.
The truck received its final preparation and its on-the-salt care from the Gale Banks organization.
The truck carried its dry sump tank, the Intake-air cooling system, and its data transmitter in the bed. Wind-tunnel testing proved that a partially flushed bed was aerodynamically better than a full tonneau.
The converted motorhome is equipped to receive telemetry information broadcast by the truck to monitor everything It does. It is even set up to offer tape playback capability so the crew and driver can watch what the on-board cameras saw during a run.
UPDATE: The GMC S-15 was returned to the salt during the annual running of the SCTA Speed Week event with the intention of attacking two records. The existing record for SCTA’s Production Coupe and Sedan Category in Engine Class E was captured with a speed of 183.942 mph with the 4.26L engine shortly before the rains shut down the event. Current plans call for a return to the salt, possibly during a World of Speed session, to go for the same class record with the 5.0L engine, which will qualify the truck for Engine Class D. Stay tuned.