IRL: Phoenix: Chevy preview

Accelerated Engine Development Is Key to Success at Phoenix International Raceway PHOENIX, March 14, 2002 -- When Chevrolet launched its first Indy car engine program in 1986, it took one year of development and 17 races for the turbocharged...

Accelerated Engine Development Is Key to Success at Phoenix International Raceway

PHOENIX, March 14, 2002 -- When Chevrolet launched its first Indy car engine program in 1986, it took one year of development and 17 races for the turbocharged Chevy Indy V8 to get up to speed and score its first victory. When Chevrolet returned to open-wheel racing this year with the new naturally aspirated Chevy Indy V8, it took two hours and eight minutes to put the red Bowtie back in the winner's circle.

The new Chevy Indy V8 was a winner right out of the box in the Grand Prix of Miami at Homestead-Miami Speedway on March 2. Designed and developed in house by GM Racing, the new Chevrolet racing engine won the pole, led all 200 laps and powered Sam Hornish Jr. to a runaway victory. It was an auspicious debut for an engine package that had never turned a lap in competition before the green flag fell.

Now Chevy will take the next step in its accelerated development program at the Bombardier ATV Copper World Indy 200 at Phoenix International Raceway on March 17. With its short straights, tight corners and heavy traffic, the fast one-mile oval in the Arizona desert makes different demands on an engine than the 1.5-mile Homestead-Miami superspeedway. It's a track that will suit the Chevy Indy V8 -- an engine that is lighter, smaller and more powerful than the Oldsmobile IRL Aurora V8 that won five straight years at PIR.

Among the Beautiful People, it's said that you can't be too thin or too rich. Among Indy car racers, the maxim is that you can't be too light or too quick. Acceleration is the key to success on a short track -- and the Chevy Indy V8 is engineered for acceleration.

Supermodels count calories, but engineers count ounces. GM Racing engineer Roger Allen and his colleagues pared weight at every opportunity when they designed the major components of the Chevy Indy V8 -- including a new block, cylinder heads, cam covers, crankshaft, pistons and connecting rods. When the diet plan was completed, these ounces added up to an 11-pound weight saving over last year's motor. The svelte Chevy Indy V8 tips the scales at 315 pounds, the minimum weight specified by IRL rules.

The distribution of this weight is also critical on a short oval. By trimming seven pounds of mass from the top half of the engine, GM engineers lowered the Chevy Indy V8's center of gravity. To appreciate the improvement in handling offered by a lower center of gravity, imagine driving a moving van and a sports car on the same winding road. While not as dramatic as the contrast between these two vehicles, seven pounds makes a difference that an Indy car racer can feel through the finely tuned seat of a driving suit.

Sophisticated computer-assisted design tools allowed GM Racing engineers to pare four pounds from the Chevy Indy V8's billet steel crankshaft without sacrificing reliability. Reducing the diameter of the crankshaft's main and connecting rod bearings paid dividends in two ways. First, the lightweight crank assembly has less rotating inertia so it accelerates and decelerates quickly in response to the driver's right foot. Second, the smaller bearings minimize frictional losses, allowing the engine to produce more power at the flywheel -- and ultimately faster speeds on the track.

The Chevy Indy V8's new dedicated cylinder head design also suits the Phoenix oval. Unlike its predecessor, which was designed for the IRL's production-based 4.0-liter engine formula, the Chevy Indy V8 is a purpose-built racing engine with intake and exhaust systems that are optimized for the current 3.5-liter displacement limit.

A do-it-yourself demonstration of the difference in port velocity between the old and new cylinder heads is as simple as turning on a garden hose: Turn the faucet wide open and the water will spray a few feet from the end of the hose. Put a nozzle on the hose and the water will spray across the yard. The water pressure and volume are unchanged, but the velocity is increased dramatically by reducing the size of the passage. It is the same for the air and fuel moving through an engine: higher velocity produces quicker response, more complete cylinder filling and faster acceleration.

Chevrolet's original turbocharged Chevy Indy V8 dominated at Phoenix International Raceway, scoring five straight victories in 1988-92 with wins by Mario Andretti, Rick Mears (twice), Arie Luyendyk and Bobby Rahal. But that was then and this is now. The new-generation Chevy Indy V8 will have to prove itself at PIR with a new generation of Indy car drivers. Fortunately, the Chevy Indy V8 has all the right moves for a one-mile oval.

-chevy-

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About this article
Series IndyCar
Drivers Arie Luyendyk , Mario Andretti , Rick Mears , Sam Hornish Jr.