The 2013 SRT Viper

If you wanted to summarize the 2012 SRT Viper, Edmunds’ Inside probably said it best:

The old Viper, too often, drove you. The new Viper you drive.

Packing an 8.4-liter V10 producing 640 horses and 600 pound-feet of torque, the SRT Viper is something you’ll want to drive.

From Chrysler’s drivesrt.com:

The updated V-10 engine has an estimated power rating of 640 horsepower at 6,150 rpm, an increase of 40 horsepower over the 2010 Viper. Producing 600 lb.-ft. of torque at 4,950 rpm, the Viper puts out the most torque of any naturally aspirated sports car in the world.

Viper’s legendary 8.4-liter V-10 engine features a new composite intake manifold, lighter forged pistons, stiffer pushrods, a revised camshaft profile, sodium-cooled exhaust valves and freer-flowing exhaust catalysts – all contributing to the 40-horsepower increase.

The new intake manifold is tuned using computational fluid dynamics (CFD), a high-performance computer-based simulation that has improved everything from Formula 1 car aerodynamics to nuclear submarine performance for silent running. The new forged pistons are not only lighter, but stronger and more durable to ensure precise piston/cylinder wall tolerances for consistent ultra-performance on the road and at the track.

Stiffer pushrods enable more precise valvetrain performance, while the revised camshaft profile works better with Viper’s variable-valve timing (VVT) for enhanced power as well as lower emissions and fuel consumption. Sodium-filled exhaust valves run cooler to help protect against fuel mixture detonation in the cylinders which, along with better engine cooling, enables more aggressive spark timing for more torque and power. A revised catalyst wash-coat process enables a 20-percent reduction in back pressure that also helps improve power output.

A Tremec TR6060 close-ratio six-speed manual transmission is standard on both the SRT Viper and SRT Viper GTS. Closer ratios make Viper even more responsive, while a new sixth gear, combined with a shortened final-drive ratio of 3.55 to 1, produces noticeably better high-speed performance. New gear manufacturing techniques produce precision-formed teeth for smooth meshing while fine-pitch synchronizers reduce synchronizer travel, giving lower shift efforts and room for 15% wider first, second and third gears for better torque handling. Reverse selection is eased by the use of a double-cone synchronizer. Shift throws are 12.5 percent shorter.

The aluminum housing of the transmission is beefed up with thick flanges and cast-in ribbing to lower stress. It is also strengthened in the shift rail area, and the rails are held in place with shorter spans. This reduces the possibility of rail flex during spirited shifting while improving shift feel.

A new lighter flywheel, aluminum for the first time-ever in a Viper, gives a further tenth-of-a-second improvement in quarter-mile performance. A self-adjusting twin-disk clutch completes the package.

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