Anatomy of a Cup Chevrolet
A variety of parts and pieces go into creating the Chevrolet Impalas that Hendrick Motorsports races each week in the NASCAR Sprint Cup Series. From the cowl induction to the deck fin, each part plays its own role and is crucial to the success of race teams. Recently, Doug Duchardt, Hendrick Motorsports’ vice president of development, helped break down the top 16. Click here to view a photo gallery break down of the parts.
No. 1 - Radiator and Brake Air Intakes: Located on the lower front bumper, these parts are used to cool the engine fluids, engine and brake components, respectively. NASCAR recently changed the radiator air intake in an attempt to keep drivers from pushing each other in tandem draft for long green-flag runs. Kurt Romberg, chief aerodynamicist at Hendrick Motorsports, gives his take on that change here. Mechanics in the Nos. 5/24 and 48/88 shops consider the type of track when determining the size of the brake air intakes. Cool air is critical to brake performance, particularly at a short track like Martinsville (Va.) Speedway where drivers stop frequently.
No. 2 - Hood Pins: These four, quick-release metal pins keep the hood closed when Hendrick Motorsports drivers are achieving top speed on the track. While personal vehicles rely on a latch to keep the hood closed, Cup teams need something that is both strong and functional in a moment’s notice. These pins are strong enough to secure the hood on track, but they also provide the crew immediate under-the-hood access during practice or at the race.
No. 3 - Cowl Induction: Air is taken in at the base of the windshield and used by the engine to make power.
No. 4 - Body Panels: Large pieces of sheet metal that cover the cars. General Motors provides Hendrick Motorsports with the roof, front and rear-fascia panels, hood and deck lid, which are made using a stamp to cut the sheet metal into the specified shape. The remaining panels are hand-fabricated by Hendrick Motorsports employees using various tools including an English wheel, to mold the material to a thickness that sometimes is within a fraction of an inch.
No. 5 - Roll Cage: A cage of steel tubing inside the car that protects the driver in case of impact or rollover. Roll cages for Hendrick Motorsports Chevrolets are manufactured on-site to meet NASCAR specifications. A staple in race cars for years, bars have been added to the roll cage as needed. Duchardt notes the bar that runs down the middle of the windshield is known as the Earnhardt bar. That became mandatory in 1996 to prevent roof collapses after Dale Earnhardt Sr. was involved in a wreck at Talladega (Ala.) Superspeedway.
No. 6 - Jack Post: Located on either side of the car and often recognizable by a yellow arrow, this is the area where jackman places the jack to lift the car during pit stops.
No. 7 - Double Frame Rail and Energy Absorbing Material: NASCAR required the addition of this material between the bars of the roll cage and the body panels after the Car of Tomorrow was introduced in 2007. NASCAR was concerned about penetration into the cockpit if a driver was hit in the door. To ensure driver safety, NASCAR requires a steel layer and energy absorbing materials between the bars of the roll cage and the body panels.
No. 8a - Window Net: Safety device located in the driver-side window that keeps the driver’s head and arms inside the car during an accident.
No. 8b - Carbon Fiber Seats: Developed by Hendrick Motorsports in conjunction with partner Delphi, these NASCAR-approved seats are built using strips of carbon fiber which dramatically reduce impact. Today, approximately 80 percent of Cup drivers use carbon fiber seats in their cars. There are 20 different shells a driver can choose from to customize his or her seat. From there, strips of padding are then molded around the driver’s body to create a secure, comfortable driving environment.
Nos. 9 and 11 - Roof Strip and Roof Flaps: Roof strips and flaps are safety features that have been developed to help race cars stay on the ground if they spin on the track. The features can be traced to 1987 and the beginning of the restrictor-plate era when NASCAR Hall-of-Famer Bobby Allison crashed at Talladega and was sent flying airborne into the catch fence. Roof strips and flaps are designed to keep air flowing over the top of the car and help keep it pinned to the ground.
No. 10 - TV Camera: NASCAR let television networks install roof cameras on race cars in the mid-to-late 1990s as a way to give fans an inside perspective. The addition of the camera was optional, but some teams discovered it offered a surprising advantage. Further wind tunnel testing revealed the roof camera slightly enhanced the aerodynamics of the car, especially when the teams could adjust its position, Duchardt said. To ensure teams didn’t have an unfair advantage or disadvantage, NASCAR mandated the location of roof cameras and the addition of dummy camera housings for teams not participating.
No. 12 - Jacking Bolts: Adjustments are pivotal for teams during pit stops to improve the car’s handling. These bolts allow pit crew members to adjust the handling of the car by altering the load on the rear springs. If an adjustment is made to the left, it affects the right-front side of the car. If an adjustment is made to the right, it affects the left-front side of the car.
No. 13 - Cooling Vents: In order to keep different aspects of the car cool, air is brought in through the rear-quarter windows. That air is delivered to the rear gear, the driver and other critical components. This year, a duct was added to direct air to cool the engine control unit.
No. 14 - Goodyear Eagle Racing Tires: Goodyear continually works on the construction and compound of its treadless radial tires to match tracks as they age or are repaved. Teams, including Hendrick Motorsports, participate in various tire tests throughout the season.
No. 15 - Rear Deck Fin: Similar to the roof flaps and strips, the rear deck fin is used as a safety feature to keep the car pinned to the track. It also functions as a tuning tool, which the pit crew can adjust to affect rear-side force. NASCAR mandated the use of rear deck fins to help prevent cars from spinning out. According to NASCAR specifications, it must be 3.5 inches tall, roughly the same height as a coffee mug, and extend no more than 25 inches across the deck lid.
No. 16 - Rear Spoiler: Directs air flowing over the rear of the car, providing downforce to improve handling and keep the back end of the car from sliding on the track. NASCAR briefly experimented with a wing during the 2008 season. Hendrick Motorsports won 27 races with the wing before NASCAR mandated a switch back to the spoiler in 2010.