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2009 Dodge Viper ACR
You're looking at Dodge's answer to the Porsche 911 GT3 RS or Lotus
Exige, a road car you can drive to the track, hot lap all day, and drive
back home, tires, brakes, and ego intact. The Viper ACR is raw. It's
wired. And it's probably the best weekend racer yet from Detroit.
The ACR has exactly the same power and torque as the regular Viper-600
horses and 560 pound-feet. The engine drives through a smaller dual
plate clutch that reduces rotating inertia by 18 percent and the latest
iteration of the Tremec T6060 six-speed that includes triple-cone
synchros on first and second, and 10-percent-wider gears to manage the
torque. The new GKN ViscoLok diff features its own sump to quicker
generate the hydraulic pressure needed to actuate the limited-slip
clutches faster, yet more progressively and with greater precision.
Most of the time, effort, and development dollars have been spent on
stuff that makes the ACR go faster through the twisty bits-suspension,
brakes, wheels and tires, and aerodynamics. Especially the aerodynamics.
Just chew on this for a moment: At 150 mph, the regular Viper coupe
generates 100 pounds of down force; at the same speed, the Viper ACR
generates 1000 pounds of down force.
That giant carbon-fiber rear wing is the most obvious reason why. But
there's also a new carbon-fiber front splitter that extends way back
under the car and incorporates seven steps to diffuse the airflow. The
new hood louvers unveiled with the 600-horsepower engine upgrade a year
ago play a part, too. "We knew we were going to do a new ACR, so we
moved the louvers forward to help change the aero balance of the car,"
says SRT boss Herb Helbig.
Suspension changes include race-style KW shocks all around that can be
adjusted for stiffness and ride height, springs twice as stiff as those
in a normal Viper, and a beefier front stabilizer bar. Forged
"Sidewinder" alloy wheels save 30 pounds of unsprung weight, and new
two-piece StopTech brake rotors save a further 30. Michelin Pilot Sport
Cup tires-basically barely legal race rubber-are standard.
The standard ACR is 40 pounds lighter than the regular Viper coupe. An
optional "Hard Core" pack saves an extra 40 pounds through the removal
of the audio system, under hood silencer pad, trunk carpet, and tire
inflator. The radio is replaced by a lightweight cover that can be
configured to mount the lap timer that comes with the package.
Hard-core, indeed. |
