Bowtie Bullet Points: Chevrolet Notes for the Pikes Peak Indy 225 Racing Around Chevrolet is competing in four major-league motorsports events this weekend. In addition to the IRL event at mile-high Pikes Peak International Raceway, Corvette...
Bowtie Bullet Points: Chevrolet Notes for the Pikes Peak Indy 225
Chevrolet is competing in four major-league motorsports events this weekend. In addition to the IRL event at mile-high Pikes Peak International Raceway, Corvette Racing is gunning for a third straight GTS class win at the 24 Hours of Le Mans in France. Bobby Labonte's Chevrolet Monte Carlo will start on the pole in the NASCAR Winston Cup Sirius 400 at Michigan International Speedway and NHRA Pro Stock points leader Kurt Johnson will race for his fifth win of the season in his ACDelco Cavalier at the NHRA Pontiac Excitement Nationals in Columbus, Ohio. Chevrolet is the only manufacturer currently competing in the IRL, NASCAR Winston Cup, NHRA and American Le Mans Series.
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. At sea level, standard atmospheric pressure is 14.7 pounds per square inch (psi), but at Pikes Peak International Raceway, which stands 5,357 feet above sea level, the pressure is only about 12 psi. This "thin air" reduces engine output by approximately 16 percent from sea level.
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 than they do at sea level, 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.
GM engines have won six of the seven IRL events contested at Pikes Peak International Raceway - 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 in every IRL event at PPIR. Ray set the absolute track speed record at 179.874 mph on June 17, 2000, driving Team Menard's Indy car powered by an IRL Aurora V8 engine.
The Long Run
Chevy Indy V8 racing engines have won a total of 100 Indy car races to date. The first-generation 2.65-liter turbocharged Chevy Indy V8 won 86 times and claimed 80 poles in CART and USAC-sanctioned events in 1987-93. Chevy returned to open-wheel racing in 2002 with the 3.5-liter naturally aspirated Chevy Indy V8 that won 14 out of 15 races and nine poles in IRL competition last season.