Building The “Purple Monster”

It’s hard to believe the fourth-generation Viper shown in these pictures arrived at Complete Performance Motorsports as a bare chassis, stripped completely of all body panels, suspension, powertrain and anything else that wasn’t permanently attached.

Originally a test mule used on public roads to evaluate performance and components, Jim Stout’s “hybrid” Viper Competition Coupe had to be built from the frame up to become the car you see here. Jeff Stout at Complete Performance Motorsports leveraged his relationship with Dodge to secure the chassis and begin the year-and-a-half construction process. CPM is one of leading Viper performance shops in the United States.

“We started a great relationship with Dodge back in 2003 when the Dodge Viper Competition Coupe was released,” said Jeff Stout, owner of Complete Performance Motorsports. His father Jim Stout, owns this Viper and Pittsburgh International Race Complex.

That relationship with Dodge led to CPM  manufacturing performance parts for Dodge for Vipers. Stout said they began making brake rotor hats, uprights, stiffeners, shock relocation kits, geometry correction kits, steering hoses. The list goes on.

To Stout, that bare chassis was akin to a blank canvas to a painter. Starting from the ground up, Stout went with all spherical bearings on the suspension. That means the camber settings you establish on the alignment rack are less likely to change much in dynamic situations.

“The cars are a pretty impressive piece. The lower control arms and the uprights or spindles as people like to call them are all made out of aluminum. They’re forged aluminum and they have rubber bushings in them,” Stout said. “We press all the rubber bushings out of them and we put spherical bearings in them, so everything’s got stainless-steel spherical bearings and it makes for a heck of a difference.”

Building the suspension for the car led to CPM beginning to manufacture alignment slugs for Dodge. The rectangular slugs are lettered to indicate their respective camber settings. Each size changes the camber by .2 degrees. CPM began making them from a different material that doesn’t deform with use and, in the case of racing, abuse. CPM also fitted the car with easy-access bolts in the rear to adjust wedge.

CPM set the car up with Penske four-way adjustable shocks and Hypercoil springs. To find the right brakes, Stout met with Mike Messina from Brembo to select the hydraulic components that would do the job of stopping the Viper. The GT3-style monoblock calipers are fitted with six pistons up front and three pistons in the rear. CPM manufactured the brackets to fit the calipers to the Viper uprights and then designed and built hats to center the rotors within the calipers. Antilock capabilities are handled by an OEM ABS unit relocated inside the passenger compartment. The car also now has center-lock hubs.

When it came time to address the car’s unibody, CPM stripped it of all it seam sealer, sound deadener and paint. Rather than leaving the factory floor in place, Stout said they fitted it with flat aluminum floor panels that span from the breakaway front splitter to the modified factory rear diffuser, which also was modified to break away. The flat floor provided aerodynamic advantages, but also weight savings over the factory steel floor. They also added a Staubli air jack system.

The power train starts with a Prefix Racing 8.4-liter dry-sump V10 that makes 780 horsepower, which is ample given the car’s 2,957-pound weight without driver. All that power is channeled through an EMCO paddle-shift sequential six-speed transmission. Dodge originally designed the Viper as an analog car, but the purple monster takes full advantage of the racing technology available today. In NASA race classing, the car competes in Super Unlimited.

For example, the Motec C185 data system communicates with the car’s OBR Control Systems electronics through a custom wiring harness built by Stout and Dave Decker from Precision Race Services, Ole Buhl from OBR Control Systems and Lee Carduccci from Prefix Racing. The four of them took a week and a half to build the harnesses and make the brackets that keep everything in place. Getting all the components to work together and having everything to communicate properly was another big task. Overseeing everything at the track is crew chief Tom Sessions.

“All three of us sitting there and myself and my group of guys running ragged at building brackets and mounts and hardware to get everything installed, it was pretty impressive. I ended up with some really good friends over all these years. Let me tell you that,” Stout said. “We went through a ton of R&D with the OBR system and the paddle shift. It was very, very painful, and that’s being polite about it.”

Even the fuel system is pretty elaborate. It’s got four lift pumps and two primary pumps. The four lift pumps feed a swirl pot and then the two primary pumps are submerged. The OBR system is so intricate it can read amperage draw or pressure drop and it can start switching through pumps and cancel out pumps until it gets the right configuration that it wants.

As you might imagine, the lessons they have learned from building this car, from configuring the brakes and the electronics, and building parts to getting everything to communicate properly, have gone into improving subsequent builds.

“Every time we build a new one, they get better, better, better,” Stout said.