WENDOVER, Utah – GM Performance Division is taking Chevrolet’s SS brand to a place it’s never been before: the Bonneville Salt Flats . Conceived in the fertile mind of Zora Arkus-Duntov, the first Super Sport Corvette was intended to make Chevrolet a force in international road racing in the ’50s. A generation of brawny musclecars wearing SS emblems left their tire tracks on drag strips across America in the ’60s and ’70s, and Monte Carlo SS stock cars have dominated NASCAR competition since the ’80s. Now the Cobalt SS Bonneville speedster – a modified version of the new 2005 Chevrolet Cobalt SS Supercharged sport compact coupe – is ready to write a new chapter in the multi-volume history of the SS line, propelled by a 21st century turbocharged four-cylinder Ecotec engine.
GM Performance Division’s expedition to Bonneville with a modified version of the new production-based Cobalt SS Supercharged is a sequel to last year’s record-setting performance with a Saturn Ion Red Line quad coupe. On Oct. 17, 2003 , GM engineer Jim Minneker piloted the Ion to a n ew mark in the G/Blown Fuel Altered class at 212.684 mph, eclipsing the previous record by nearly 30 mph. Now with a new car, a new driver (NHRA Sport Compact drag racing champion Nelson Hoyos) and a proven Ecotec engine, GM and the So-Cal Speed Shop team are aiming to raise the bar even higher.
“The Saturn Ion Red Line and the Cobalt SS Supercharged are both based on GM’s new Delta platform,” explained GM Performance Division Executive Director Mark Reuss. “The Saturn chassis that we raced last year was very close to stock specifications, and what we learned was applied directly to this year’s production Cobalt SS Supercharged. When you run at extreme speeds, you learn very quickly where to spend your time on development. This year’s Cobalt SS Bonneville speedster is designed to run even faster, so we built a more race-oriented chassis to maximize safety.”
The production Cobalt SS Supercharged has strong performance credentials in factory trim. Powered by a supercharged and intercooled 205-horsepower, 2.0-liter Ecotec DOHC four-cylinder engine and equipped with a tenacious suspension developed on Germany’s famed Nurburgring race track, the production Cobalt SS Supercharged will bring more heat to the already red-hot sport compact segment.
“Our goal is to build enthusiasm around a car and an engine that we are very excited about,” said GM Concept Vehicle Project Manager David Bolognino. “This year we’re racing at Bonneville under the Chevrolet banner with a brand-new car that’s aimed at young performance enthusiasts and an Ecotec motor that’s quickly becoming the small-block V-8 of four-cylinder engines.”
The production Cobalt SS Supercharged uses a 2.0-liter engine with forced induction, and so does the race car. The Bonneville racer’s turbocharged 2.0-liter Ecotec engine was originally developed by GM Racing for Sport Compact drag racing, where it won NHRA championships in the PRO FWD and Hot Rod classes in 2003. The race-prepared Ecotec engine and Hydra-Matic automatic transmission have proven utterly reliable under the vastly different demands and duty cycles of quarter-mile sprints and high-speed record runs that subject components to punishing loads and withering heat.
“We dyno tested the turbocharged Ecotec race motors at wide-open throttle for 36 minutes in our durability tests last year,” said GM Racing engineer Russ O’Blenes, “and we had perfect reliability. In fact, we did all of our testing and record runs with one engine last year, and then used that same motor to test the new Cobalt. That engine will be our spare for this year’s runs at Bonneville, and we still haven’t taken it apart. It’s built to the same specifications outlined in GM Racing’s Ecotec engine manual for Sport Compact drag racing. I think that proves both the performance and the reliability of the Ecotec components that are available to everyone.”
The Cobalt SS Bonneville speedster was built to the standards prescribed by the Southern California Timing Association (SCTA), the organization that sanctions the Bonneville Speed Week. A roll cage constructed of 1.750-inch diameter-by-.120-inch wall steel tubing surrounds the driver. A 22-gallon tank filled with ice and water replaces the passenger seat; an electric pump circulates the cold liquid through an air-to-water intercooler that chills the intake charge. A 33-gallon water tank occupies the space usually reserved for the back seat; this reservoir supplies coolant for the engine and eliminates the need for a conventional radiator. A trunk-mounted 16-gallon fuel cell carries the methanol fuel consumed by the engine and helps to balance the weight distribution.
In keeping with the grassroots tradition of Bonneville, the Cobalt SS Bonneville is a simple, straightforward race car.
“The Cobalt SS Bonneville speedster is really very close to a production car,” said Bobby Walden, crew chief for the So-Cal Speed Shop team, GM Performance Division’s technical partner in the Bonneville program. “The floorpan and firewall are basically stock, and none of the exterior body panels have been modified. This is a car built by hot rodders following the specs in the rulebook, and there aren’t any tricks or secrets. It’s just a straightforward approach to Bonneville racing that a guy could build in his garage.”
There are a few high-tech touches, however. The four-speed Hydra-Matic automatic transmission can be shifted electronically by pushing buttons on the steering wheel spokes. The Cobalt’s 10-inch rear wing and spill plates were developed in the wind tunnel to enhance stability, along with NASCAR-style roof flaps that are designed to keep the car on the ground in the event of a high-speed spin.
“Our goal was to maintain as much of the production Cobalt’s identity as possible in the race car, with only minor aerodynamic enhancements,” said Kip Wasenko, director of design for GM Performance Division. “The SS heritage is an important part of what makes Chevrolet a great American brand. Now we’re getting outrageous power and performance out of a new breed of small-displacement, high-tech engines.”
With an aerodynamic new design, a powerful engine and a seasoned crew of Bonneville fanatics, the followup to GM Performance Division’s record-setting performance promises to be as thrilling as the original.
Cobalt SS Bonneville Speedster Specifications
Chassis: Steel space frame with tubular steel roll cage
Body: Steel with fiberglass panels
Height: 50.5 in/1282 mm
Length (including parachutes): 195 in/4953 mm
Width: 67.9 in/1725 mm
Wheelbase: 103.3 in/2624 mm
Track: 58.8 in/1494 mm front; 58.4 in/1483 mm rear
Weight (including driver, fuel and ballast): 3900 lbs.
Engine: 2.0L Ecotec I-4
Displacement: 122 ci/1998 cc
Horsepower: 700+ @ 8700 rpm
Torque: 575 lb.-ft. @ 6000 rpm
Compression ratio: 10.5:1
Turbocharger boost: 22 psi
Transmission: GM Racing modified Hydra-Matic 4T65-E 4-speed automatic
Suspension: Modified Cobalt strut-type independent with coil springs front; modified Cobalt semi-independent torsion beam with coil-over springs rear
Wheels: Budnik billet aluminum
Tires: 26.0 x 4.5 - 15 Goodyear Eagle Frontrunner
Brakes: Disc front and rear