Stewart Doubles with GM Power
Contact: Rick Voegelin
rickvoegelin@compuserve.com
GM Racing Communications
(831) 761-2201
Tony Stewart Doubles Up with GM Power in Indianapolis and Charlotte
INDIANAPOLIS, May 23, 2001 -- Question: What has 16 cylinders, 48
valves, five camshafts and produces 1,365 horsepower?
Answer: The two GM racing engines that will propel Tony Stewart in
his quest to win both the Indianapolis 500 and the NASCAR Coca-Cola 600 on
May 27.
Stewart will rely on two very different powerplants in his 1,100
mile racing odyssey. A 3.5-liter (214-cubic-inch) Oldsmobile IRL Aurora V8
powers the Target Chip Ganassi Racing G-Force Indy car that he will pilot
at Indianapolis Motor Speedway. The Joe Gibbs Racing Home Depot Pontiac
Grand Prix that he will drive at Charlotte Motor Speedway is propelled by
a 358-cubic-inch GM SB2 small-block V8.
Stewart last attempted the "double" in 1999. He finished ninth in Indy
and fourth in Charlotte, completing 1,090 exhausting miles.
"When I got out of the car in Charlotte in 1999, I said I was never
going to do it again," said Stewart, "but the next day I had already made
up my mind I was going to try it again somewhere down the road. I just
didn't realize it would be this soon."
Stewart will start his fifth Indy 500 from the inside of the third row.
He qualified seventh with a four-lap average of 224.248 mph, the fastest
speed among the four Ganassi Racing drivers who qualified for the 33-car
field.
Stewart will rely on two racing engines that have little in common
except eight cylinders -- and the same birthplace at GM Racing in Warren,
Mich. Both motors were developed by GM engineers to meet the specific
requirements of the Indy Racing Northern Light Series and the NASCAR
Winston Cup Series.
Indy car and stock car engines based on production GM designs
The IRL Aurora V8 is based on the design of the production Aurora V8
that debuted in Oldsmobile's flagship sedan in 1994; the SB2 Winston Cup
engines is a descendant of the legendary Chevrolet small-block V8
introduced in 1955. The Indy car engine's methanol fuel is metered by
electronic fuel injection, while the stock car motor's four-barrel
carburetor dispenses racing gasoline. The IRL Aurora V8 relies on four
overhead camshafts that operate 32 titanium valves; the SB2's valvetrain
employs a single block-mounted camshaft, pushrods and rocker arms to
operate 16 titanium valves.
With 144 fewer cubic inches, GM's Indy car engine has 40 percent
less piston displacement than its NASCAR cousin. What the IRL engine lacks
in size, however, it makes up for with its higher operating speed. The IRL
Aurora V8 revs to an IRL-mandated 10,700 rpm redline, while the NASCAR
small-block operates under 9,000 rpm.
Despite the differences in specifications and hardware, the two
engines produce very similar output. A typical stock car small-block
without a restrictor plate produces 715 horsepower, approximately 10
percent more than its 650-horsepower Indy car counterpart.
An astute driver like Stewart can feel this difference in the seat of
his driving suit. "The IRL Oldsmobiles are a lot smaller than the Pontiac
engines we race in Winston Cup, so they have less acceleration when I stand
on the throttle," he explained.
Indy car "tennis ball" versus stock car "bowling ball"
The cars that Stewart will drive in Indy and Charlotte are also
worlds apart. Constructed of carbon fiber and composite materials,
Stewart's open-wheel Indy car weighs just 1,550 pounds. The tube-framed
Grand Prix he drives in NASCAR weighs more than twice as much, tipping the
scales at 3,400 pounds.
"When I compare how I drive an Indy car with how I drive a Cup car at
the Brickyard, it's like the difference between a tennis ball and a
16-pound bowling ball," Stewart laughed. "When you get to the end of the
straight in an Indy car, you can run it wide open if it's driving right. In
a Winston Cup car, you always have to lift off the throttle and get on the
brakes no matter how good it's driving."
NASCAR has high profile at Indy 500
The presence of prominent NASCAR personalities at this year's Indy
500 recalls the days when stock car drivers like Cale Yarborough and Bobby
Allison made the annual pilgrimage to Indianapolis. Former NASCAR driver
Robby Gordon is qualified on the outside of the front row in an
Oldsmobile-powered Dallara that is co-owned by auto racing legend A.J. Foyt
and championship-winning NASCAR team owner Richard Childress.
Gordon echoes Stewart's thoughts on the differences between the two
types of race cars. "You can drive an Indy car a lot harder than you can
drive a stock car because an open-wheel car is lighter, they have more
downforce and the tires are wider," Gordon said. "You can manhandle an Indy
car a lot longer than you can a stock car."
Despite the differences in equipment, success in motorsports
ultimately depends on the human element. "I believe if you can drive a race
car, you can drive any race car," Gordon observed. "Jeff Gordon proved you
can go straight from sprint cars to NASCAR. Tony Stewart has gone from
sprint cars to Indy cars to NASCAR, and he's won in every series."
What motivates a driver like Stewart to attempt the daunting double
again? "I want to win," he declared. "I'm a racer. I'm not worried about
making sure I get to dinner on time."
With a pair of GM engines to power his dream, Tony Stewart is ready
to make racing history on May 27.
How They Compare: IRL Aurora V8 vs. NASCAR SB2
Displacement 3.5 liters (214 cubic inches) 358 cubic inches
Horsepower 650 @ 10,700 rpm 715 @ 7,800 rpm
Fuel Methanol Gasoline
Induction Electronic fuel injection 830 cfm 4-barrel
carburetor
Valvetrain Four overhead camshafts One cam, pushrods and
rocker arms
Compression 15:1 12:1
Cylinder Heads Aluminum, four valves/cylinder Aluminum, two
valves/cylinder
Block Aluminum Cast iron
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E-mail from: Rick Voegelin, 23-May-2001
