Designs on the Winner's Circle

Safety at any speed and an even shot to grab the checkered flag keeps the IRL IndyCar Series going strong. Scott Dixon and his No. 9 Target Chip Ganassi team took the checkered flag at the Toyota Indy 300 at Homestead-Miami Speedway. The 2003 Chevy Indy V8 is 3-in. narrower, 3-in. shorter, and 35 lb lighter than the 2002 engine. HPD and Ilmor worked together as technical partners to design, develop, and build the Honda HI3R Series Indy V-8. The Toyota Indy V8 produces more than 675 hp. In this photo from Honda Indy Racing, the Andretti Green Racing crew works late into the night on the No. 11 car driven by Tony Kanaan. The new Panoz G Force chassis, designed and manufactured by Elan Motorsports Technologies, Braselton, Ga., has high sidepods sloping downward as shown here on the No. 21 car driven by Felipe Giaffone. This Memorial Day weekend, Indianapolis again becomes the center of the motorsports universe with the running of the 87th Indy 500. This year's race shines the spotlight on a new three-year engine and chassis specification package. The new plan, as always, focuses on driver safety and more competition. Look for a shakeout among engine providers -- GM, Honda, and Toyota are in, Nissan is out -- as well as more robust chassis and redesigns galore from nosecone to powerplant to gearbox. Competition in the IRL has never been more fierce. This year three engine makers will battle it out on the track. , Detroit, returns with an all-new Chevy Indy V8, the second new IndyCar engine produced by the team in just two years. threw its hat into the ring last spring, announcing , Costa Mesa, Calif., would design and build an engine to compete beginning this year. And American Honda Motor Co. Inc. is making its initial foray into the IRL IndyCar Series. Leading its engine design and development effort was the company's racing subsidiary , Santa Clarita, Calif., and technical partner , Plymouth, Mich. Long-time IRL engine supplier pulled out of the IndyCar Series, instead focusing its efforts in 2003 on the IRL Infiniti Pro Series. GM Racing has been powering IndyCars to victory since the IRL introduced naturally aspirated engines in 1997. The powerplant producer is working around new and carried-over IRL specs. The IRL engine formula still calls for a maximum displacement of 3.5 liters (214 in. ), and a 180° flat crankshaft. Maximum engine speed, however, has dropped from 10,700 to 10,300 rpm, regulated by a programmable rev limiter. The IRL rev limiter is basically the "policeman" of the race -- its limit is inviolable. But, within the GM engine-control module (ECM) is another limiter, there to avoid triggering the IRL limiter. It has "hard" and "soft" limiting features used at the engineers' and engine builders' discretion. According to GM, two "hard" limiters within the IRL Chevy Indy V8 shut down the engine's ignition system when it hits 10,300 rpm. A third "soft" limiter progressively cuts spark to the cylinders as engine speed nears the limit. "The IRL limiter is called a hard limiter because when it activates, it shuts down the entire ignition system," says GM Racing engineer Ned Baker. "It's like an on-off switch. When the limiter is activated, engine output drops to zero. The limiter doesn't restore current to the ignition system until is has determined the engine is below the rpm limit, so there is a period when the car is essentially without power." The rev limiter figures engine speed by measuring intervals as four teeth on a flywheel pass a block-mounted sensor. It also contains a data logger that IRL officials can access any time during an event. According to Baker, the hard limiter is extremely harsh so the second rpm limiter is set just below the IRL limit threshold. "The ECM calculates engine speed just as the IRL limiter does, but uses its own sensors and logic," he says. When activated, the internal electronic-control-unit (ECU) limiter shuts off the signal to the ignition module. The interruption may only last a thousandth of a second, but