Chevys revving up new powerplant for Texas
By Seth Livingstone
USA TODAY
Chevy is putting a NASCAR dinosaur on the road to extinction.
As many as seven Chevrolets in this week's Samsung 500 at Texas Motor Speedway could be running the new RO7 engine.
The RO7 is being phased in to replace the venerable SB2 block, a design that's been in use with minor revisions since 1955.
In addition to Joe Gibbs Racing cars driven by Tony Stewart, Denny Hamlin and J.J. Yeley, the Hendrick Chevrolets of Kyle Busch and Casey Mears also are expected to employ the new engine. Hall of Fame Racing's Tony Raines (running a Hendrick engine) and Scott Wimmer (out of the Richard Childress garage) also are making the change.
Chevrolet teams have had the new engine at their disposal for several weeks but have been reluctant to make the switch, particularly with all the changes necessitated by the Car of Tomorrow the past two races. There's been little reason to mess with success as Chevrolets have dominated the first six races, winning five, including the Daytona 500.
Wimmer was the first to debut the RO7 when he just missed qualifying at Atlanta Motor Speedway on March 16.
In Chevy showrooms, the old SB2 (small block, second generation) engine has gone through numerous incarnations, from its 265-cubic-inch origins to its 283, 327, 307, 305 and the long-running 350ci brethren. The new, computer-designed model with a maximum 358-cubic-inch displacement won't be put into general production, according to Jim Covey, engine technical director for General Motors Racing, but principles proven on the track will lead to everyday advancements.
"This is the first time NASCAR has offered us a clean sheet of paper and we've been able to use all the analytical tools and resources of General Motors," Covey says. "The 1955 Chevrolet engine was never expected to run anywhere near 850 horsepower."
What advancements have been made?
"One of the biggest differences is that the new engine provides targeted cooling," Covey says. "You use less water to cool more efficiently.
"An engine is basically an air pump. The idea is to make the most efficient air pump possible. Whether it's about making horsepower or providing fuel economy, it's all about efficiency."
Chevrolet's new engine is debuting in Nextel Cup cars but likely will trickle down to the Busch and Craftsman Truck series by 2009. The prospects are exciting to Chevy teams, who have long been successful with the SB2 but find themselves spending more man hours than ever to keep up with more-modern Ford and Chrysler designs.
"We've finally got us a modern engine," says team owner Richard Childress. "Not that the other one was bad. The old 350 is still a great engine with good power. We win races with them. But the labor and time and effort it takes to prepare them, compared to what these other manufacturers do, is unbelievable."
In recent weeks, Chevrolet teams have struggled with fuel pump problems, resulting from cable-driven pumps mounted externally, atop the fuel cell, rather than hydraulic pumps mounted to the side of the engine.
Covey says that although all teams are currently running the cable version with the RO7, an alternative will be available to mount the fuel pump to the timing belt cover.
All Chevy factory teams will soon be racing the engine in both the Monte Carlos and Impalas (Car of Tomorrow), but no timetable for a complete changeover has been mandated.
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