Bristol: GM Racing preview

Chevy Cobalt Ready To Enter NHRA Pro Stock Arena Makes Debut This Weekend At Bristol Dragway BRISTOL, Tenn., April 29, 2005 - It should come as no surprise that the introduction of the Chevy Cobalt has bowled over showroom audiences nationwide.

Chevy Cobalt Ready To Enter NHRA Pro Stock Arena
Makes Debut This Weekend At Bristol Dragway

BRISTOL, Tenn., April 29, 2005 - It should come as no surprise that the introduction of the Chevy Cobalt has bowled over showroom audiences nationwide. Targeting the premium small-car buyer, the Cobalt is intended to deliver a driving experience not expected in the compact-car segment, along with a higher level of refinement, quality and performance. Now the American Revolution that is uniquely Chevrolet comes to the NHRA with the debut of the Pro Stock Cobalt at Bristol Dragway on April 29.

"Chevrolet's performance heritage promises cars that are dependable, capable and exciting to drive," said Jim Campbell, Chevrolet car marketing director. "In 2005 the Chevy Cobalt puts the fun back into driving by delivering an experience never before seen in the compact-car segment. The Chevy red bowtie competes to win, has a strong heritage in drag racing and is one of America's most successful automotive brands. The NHRA Pro Stock Cobalt is designed, built and engineered to continue that winning tradition."

In November 2003, GM Racing engineers began kicking around rough ideas for the creation of a competitive Chevy Cobalt Pro Stock car. Taking an advanced model of the production car, they headed to Don Ness Racecraft just north of Minneapolis, and along with Ness and representatives from the NHRA (including National Technical Director Danny Gracia), started going over some basic styling features for the new car.

For the first time ever, the NHRA began implementing over 20 minimum dimensions for the construction of Pro Stock cars, including the Cobalt. The new mandates cover such obvious areas as height of the car, width of the car, front overhang, rear overhang, etc.

"The first thing we had to do was make sure the car fit within the box," explained Dan Engel, GM Racing program manager, NHRA Drag Racing. "Those are minimum dimensions so you want to get down to that without changing the basic shape. Danny Gracia thoroughly went over the model and specifically marked off how it was to comply. The nice thing is that NHRA was involved from the very start. Like everyone at GM, they were also interested in the car's final outcome, that it still look like a production car while keeping a lot of the body lines and contours of the Cobalt. We're racing Cobalts so we want the cars to look like Cobalts."

With the production version of the Cobalt, GM Racing engineers had a pretty good baseline to begin the planning and construction of the Pro Stock Chevrolet. Extensive research was conducted in the GM wind tunnel in Warren, Mich., experimenting with various greenhouses, decks, roofs and fender flares to determine the most aerodynamically efficient race design.

"The Cobalt was a great car to start with," explained Engel. "Obviously, it's a lot easier to start off with a smaller car than a big car, but the biggest hurdle we had was making enough room underneath the hood to get that 500 cubic-inch DRCE engine in there. We were able to get the body to meet all the dimensions mandated by NHRA, fit the engine, the rear axle, the entire chassis, and still retain the production shapes and contours of the production Cobalt."

In addition to improving on the aerodynamics and design of the older Cavalier model, GM Racing engineers were looking to accomplish two other objectives with the Cobalt. The first goal was to create a one-piece body, or unibody that would make it more efficient for chassis builders to mount and work with, and for the NHRA Technical Department to inspect. The second was to reduce the weight of the body while still keeping its stiffness, strength and structural integrity.

"Whenever we create a new racecar we try to accomplish more than just introducing a new model," Engel said. "We also want to apply everything we've learned since building the older design so that we can keep moving forward, whether it's in the area of aerodynamics, strength of the body, safety, etc., and these were two areas we felt we could improve upon."

On the current Cavalier, the nose, hood, quarter panels and front valance are all contained in one piece. However, the back end of the race car is comprised of many different components including a right and left quarter panel, the roof, rear deck, rear deck filler panel and bumper cover. Before the new Cobalt, chassis builders had to worry about lining up the various seams correctly at the correct angles to make a perfect fit for the template. The NHRA was also in favor of the unibody style because it would make it easier to check the car when it's going through tech inspection at the racetrack. By making everything one piece there's less chance for mistakes and discourages attempted violations.

"We had great input from NHRA throughout the entire project," Engel. "They were even at the second wind tunnel test when we made some minor tweaks and changes to the car, and we provided them with all the aero numbers. They've been tremendous to work with."

After the second wind-tunnel test, Five Star began the process of creating the molds which were used to make the actual body panels. But before they could make the molds, there was a lot of prep and finish work to be completed to make sure the body was perfectly smooth and symmetrical from left side to right side.

"Before you make a template, it has to fit perfectly," explained Engel. "You can stand there and look at a body and say, 'that's pretty symmetrical,' but that's not good enough. You have to be very precise."

After the molds were completed, Five Star created a Cobalt body that was sent back to Ness Racecraft where it was mounted on a chassis. After the body was mounted, the NHRA again went through the process of checking dimensions, and at this point the templates were made.

"We build the first set of production templates at Don Ness' shop," said Engel. "We give them to NHRA and they become their master set. Besides measuring the car, NHRA also checked out the templates to make sure they fit the car. Since these are the templates GM has built under the supervision of NHRA, these will be the templates now used at the racetrack. When NHRA gives their final approval then we start kicking Pro Stock Cobalt bodies out of Five Star, and they can do two or three every week."

A second objective of GM Racing engineers was to take weight out of the body without reducing the stiffness or strength of the new Cobalt.

"We always like to have the cars as light as possible," said Engel. "You still have to stay within the 2350-pound rule for car weight but we'd rather put the ballast where we prefer, and have room to add ballast from a weight standpoint."

Working with Five Star, GM was able to lower the weight of the new Cobalt body by going to a different laminate schedule, or a variation and quantity of the materials used to create the new car.

"Besides deciding what materials you're going to use, you have to determine how much of each you're going to use, or what density, so there's quite a bit of research that goes into the laminate schedule," Engel explained. "It's a fairly detailed, well thought out plan and very proprietary - a recipe so to speak. You just can't say we're going to use fiberglass and carbon fiber and glue them together. Various combinations of carbon fiber, fiberglass, E-glass (which is a type of fiberglass), Kevlar (same material used in bullet-proof vests) and honeycomb are in the Cobalt. We were actually able to reduce the weight by about 10 pounds yet make it a little stronger and stiffer."

After 18 months of diligent research and development, hard work and the pressures of meeting the competition demands of their on-track constituency, GM Racing engineers are more than pleased with the new Chevy Cobalt.

"The aero numbers have certainly improved with the Cobalt, so from that standpoint it will be better," said Engel. "But different drivers are used to the way they like their cars handling. Some drivers like a little bit more front downforce to give them a better feel for the steering, some drivers like a little less on the front, but relative to the front to rear, you need balance so there's not too much on the front or too much on the back, and this car provides that."

The Pro Stock competitors who will race the new Cobalts, including ACDelco Chevrolet driver Kurt Johnson and Valvoline Chevrolet driver Ron Krisher, are looking forward to climbing into the new design.

"It's a nice looking car," said Johnson. "It's sleek, narrow, better in the wind tunnel and early indicators show that it will be faster. We should be in great shape. We'll see what it likes, make whatever adjustments we need and go from there. It's a win-win situation for us. It's always positive any time you get the improvements of a new race car and the new Cobalt is definitely a great package."

"We're confident everything will come together with this new racecar," said Krisher. "We've already got a lot of horsepower and this new Cobalt should put the icing on the cake for us. From what we've seen and with the little testing we've done with it, it's going to be fast."

General Motors Corp. (NYSE: GM), the world's largest automaker, has been the global industry sales leader since 1931. Founded in 1908, GM today employs about 324,000 people around the world. It has manufacturing operations in 32 countries and its vehicles are sold in 200 countries. In 2004, GM sold nearly 9 million cars and trucks globally, up 4 percent and the second-highest total in the company's history. GM's global headquarters are at the GM Renaissance Center in Detroit. More information on GM can be found at www.gm.com.

-gm racing-

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Series NHRA
Drivers Kurt Johnson , Jim Campbell