IRL: General Motors simulates Indy 500 on Dyno

Relentless Engine Testing Is a Dress Rehearsal for Indianapolis 500 DETROIT, May 15, 2001 - GM Racing engineer Scott Peterson has never turned a lap on Indianapolis Motor Speedway, yet he has completed dozens of Indianapolis 500 races....

Relentless Engine Testing Is a Dress Rehearsal for Indianapolis 500

DETROIT, May 15, 2001 - GM Racing engineer Scott Peterson has never turned a lap on Indianapolis Motor Speedway, yet he has completed dozens of Indianapolis 500 races. Peterson's "race car" is a computer-controlled engine dynamometer that can precisely simulate a complete 500-mile race. Peterson and his colleagues relentlessly dyno test Oldsmobile IRL Aurora V8 engines to ensure that they can withstand the stresses they will encounter in the Memorial Day classic.

"Our primary goal is to make sure that every part in the engine can go 500 miles," said Peterson. "We put more pressure on the components than any driver. When we come up with a new design for a camshaft, piston, valve spring, or any other part, we put it through a 500-mile durability test. If it survives and passes inspection, the new piece becomes part of the GM engine kit."

A dyno cell is a torture chamber for racing engines. Not even thick concrete walls and double-pane safety glass can muffle the scream of an IRL Aurora V8 running on its 10,700 rpm redline. Shackled with wires and probed by sensors, the engine is pushed to the limits of its endurance. Peterson, 27, is the taskmaster who oversees these engine torture tests.

Computer program recreates Indy 500

Peterson conducts his race simulations at Katech, Inc., GM Racing's development partner in Clinton Township, Mich. As the computer automatically regulates the dyno, it is easy to visualize the engine speed climbing as the car streaks down the straightaway and falling as the tires scrub off speed in the corners. Occasionally the computer lifts off the throttle as the phantom driver encounters traffic, and then runs wide open again on a clear track. After 32 exhausting cycles (the equivalent of 80 miles on the 2.5-mile speedway), the computer gives the engine a brief respite during a simulated pit stop while technicians connect a fresh drum of fuel.

"The data for the simulation program came directly from a qualification run at Indy," Peterson explained. "There are 55 distinct steps as the engine accelerates and decelerates. These steps represent the aerodynamic and mechanical forces that affect the car. The test schedule is the equivalent of running a 41-second lap at an average speed of 220 mph.

"The dyno simulation is more demanding than any race because there are no caution periods that allow the engine to breathe," Peterson noted. "The dyno simulation subjects the pistons, rod bearings and piston pins to loads that are much higher than they experience in an actual racing environment."

Testing enhances GM's winning record in IRL

The benefits of this rigorous testing are apparent on the racetrack. Oldsmobile engines have won 40 of 41 races (including four straight Indianapolis 500 victories) since the Indy Racing League introduced its naturally aspirated engine formula in January 1997. Durability tests have also dramatically improved reliability; Oldsmobile engines have completed more than 200,000 racing miles in IRL competition.

"The testing program also validates the quality of parts we have previously released," Peterson continued. "When we are testing new pistons, for example, we are also testing the crankshaft, the timing chains, and every other part in the engine. In the last 18 months, GM Racing has tested 35 motors and completed thousands of miles of simulated track tests."

Racing also benefits young GM engineers like Peterson. After he completes a two-year "tour of duty" with the IRL program, Peterson will return to GM Powertrain's advanced engineering group to design engines for future GM cars and trucks. He will take with him a thorough knowledge of high-output powerplants and an innovative approach to problem solving.

"Racing has taught me the value of rapid engineering," Peterson said. "An engineer has to do the job right the first time on a racetrack. I've learned what it takes to make horsepower and torque, while on the production side we have to focus on fuel economy and emissions. Running the Indy 500 dyno simulation program has been a real education."

GM Racing's commitment to continuous improvement has given Oldsmobile's IRL Aurora V8 the power, stamina and reliability that have made it the dominant powerplant in the IRL. Peterson will continue his dyno testing program until the green flag flies on May 27. Even when the IRL Aurora V8 racing engines at the famed speedway are silent, other Oldsmobile racing engines are screaming in a dyno cell in suburban Detroit.

-GM Racing-

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Series Automotive , IndyCar