Bowtie Bullet Points: Chevrolet Notes for the Honda Indy 225 * Into Thin Air The IRL IndyCar Series will head for the hills for Sunday's Honda Indy 225 at Pikes Peak International Raceway near Colorado Springs, Colo. Nestled in the Front...
Bowtie Bullet Points: Chevrolet Notes for the Honda Indy 225
* Into Thin Air
The IRL IndyCar Series will head for the hills for Sunday's Honda Indy 225 at Pikes Peak International Raceway near Colorado Springs, Colo. Nestled in the Front Range of the Rocky Mountains, PPIR literally stands above the other circuits on the IRL tour at an elevation of 5,357 feet. The high-altitude oval requires adjustments in the engine and chassis specifications to compensate for the thin air at more than a mile above sea level.
The naturally aspirated engines used in the IRL IndyCar Series depend on atmospheric pressure - the force produced by the weight of the Earth's atmosphere - to fill their cylinders with fuel and air. Standard atmospheric pressure is 14.7 pounds per square inch (psi) at sea level, but at PPIR the pressure is typically around 12.2 psi. This "rare air" reduces engine output significantly.
"This weekend's race is the first time that we will run the 3.0-liter version of the Chevy Indy V-8 at a high-altitude track," said Joe Negri, GM Racing IRL program manager. "Pikes Peak International Raceway is a unique facility, and we'll go there with an engine combination that we use only once a year.
"Any naturally aspirated engine loses power in proportion to the reduction in atmospheric pressure," Negri explained. "The lower air density at high altitude reduces the oxygen that is available for combustion and therefore decreases horsepower. Reliability is typically very good at PPIR because the engines are operating well below their maximum output.
"Even though we will experience a significant reduction in power at altitude, the cars still run exceptionally fast at PPIR because there is less aerodynamic drag. And since the engines don't make as much power, we expect fuel economy to be higher than at equivalent 1-mile tracks. That could have an impact on the teams' race strategies."
* The Air Force
The lower air density at the mile-high PPIR oval also affects the race cars' aerodynamics and cooling. The wings and underbody venturis produce less downforce and drag at altitude, and the thinner air is less effective in removing heat from the radiators. GM Racing engineers, working with Chevrolet IRL teams, make adjustments in engine systems and aerodynamic packages to compensate for the unique conditions encountered at PPIR.
"The air density at Pikes Peak International Raceway is about 80 percent of normal, so the IRL race cars lose about 20 percent of their downforce compared to sea-level conditions," said Kevin Bayless, GM Racing's aerodynamics and chassis specialist. "Although the IndyCar Series introduced a new aero package, the setups won't be radically different from previous years. The 10-degree banking at Pikes Peak helps to counteract the loss of aerodynamic downforce, and the fast drivers will probably be able to run flat out in qualifying. For the race, however, the teams would normally add a couple hundred pounds of downforce. That becomes difficult at PPIR because the changes you would make at a sea-level track aren't as effective because of the thinner air.
"Along with less horsepower and less downforce, there is also less cooling efficiency," Bayless noted. "That's because there is approximately 20 percent less air flowing through the coolers to dissipate heat. The openings in the sidepods that supply air to the radiator must be opened up in order to achieve adequate cooling capacity."
* Pikes Peak Revisited
GM engines have won six of the eight IRL events contested at Pikes Peak International Raceway. GM's roster of winners includes Tony Stewart in 1997, Kenny Brack in 1998, Greg Ray in June and August 1999, Buddy Lazier in 2001 and Gil de Ferran in 2002. GM drivers have started on the pole seven times at PPIR. Ray set the PPIR qualifying speed record at 179.874 mph on June 17, 2000, driving Team Menard's Indy car powered by a 3.5-liter IRL Aurora V8 engine.
* Chevrolet Drivers on Pikes Peak International Raceway
ALEX BARRON, Red Bull Cheever Racing Chevrolet Dallara:
"Having not raced there for a while, my only memories of Pikes Peak are of the big hail storm there in 2002. Due to the high altitude, there is a lack of downforce, but Pikes Peak is one of the better tracks that we race on because of there is a lot of passing."
TOWNSEND BELL, Panther Racing Menards/Johns Manville Chevrolet Dallara:
"I'm excited about getting to Colorado Springs and racing at Pikes Peak. We're still frustrated that things didn't turn out right in Kentucky, but everybody has moved on and turned their focus to getting it right this weekend. I think we've taken some huge steps in our five races together. Johns Manville is headquartered in Denver, so I'm excited about meeting some people from there and putting on a show for them at the race on Sunday."
ED CARPENTER, Red Bull Cheever Racing Chevrolet Dallara:
"I've raced at Pikes Peak quite a bit when I raced in USAC. It's always a unique track to run with the high altitude, due to the lack of downforce and the way the engine runs. I'm looking forward to getting back on the track and keeping my momentum going."
FELIPE GIAFFONE, Team Purex Dreyer & Reinbold Chevrolet Dallara:
"I'm looking forward to getting back to a 1-mile oval. I love going back there because it's a fairly smooth track, plus it's a great city, with so many things to do. I've had good qualification runs there, but it's very tricky to find the setup to last the entire race. I remember in the past I've been fast for a few laps, but then the track changed a lot during the race. It should be interesting as a two-day event because everyone is going to have to sort things out very fast."
TOMAS SCHECKTER, Panther Racing Pennzoil Chevrolet Dallara:
"I was able to run very well at Pikes Peak last year. We had a good car and a good race, and I remember that the Pennzoil Panther car was very good there, as well. The Panther team has given me great race cars all year long, and I'm sure they will again this weekend. I'm really looking forward to racing in Colorado. It's always an exciting race."
* Racing Across America
Chevrolet will be represented in five major motorsports series this weekend. While six Chevy-powered Indy cars compete at Pikes Peak International Raceway, Chevrolet Monte Carlo coupes will race in the NASCAR Nextel Cup and Busch Series events at Michigan International Speedway. Chevy drag racers will put their Monte Carlo Funny Cars and Pro Stock Cavaliers through their paces in NHRA competition in Memphis, Tenn., and the Corvette Racing team will aim for its eighth straight victory in the American Le Mans Series at Elkhart Lake, Wis. Chevrolet is the only manufacturer that currently competes in America's premier stock car, open-wheel, drag racing and road racing series.
* About GM
General Motors Corp. (NYSE: GM), the world's largest vehicle manufacturer, employs about 325,000 people globally. Founded in 1908, GM has been the global automotive sales leader since 1931. GM today has manufacturing operations in 32 countries and its vehicles are sold in 192 countries. In 2003, GM sold nearly 8.6 million cars and trucks, about 15 percent of the global vehicle market. GM's global headquarters is at the GM Renaissance Center in Detroit. More information on GM and its products can be found on the company's consumer website at www.gm.com.