The Dodge Viper has always been a fast and fearsome thing. So much so that Matt Hardigree once opined that giving one away on a game show was like signing someone’s death warrant. Still, the rate of acceleration was always held back by the driver’s ability with a stick shift. However, one shop has changed all that, giving the Viper a transmission “upgrade” to fling it ever faster towards the horizon.
Remember the Getrag GS7D36SG? It’s a dual-clutch transmission used in a wide range of BMW performance models (E9x M3, F10 M5, F8x M2, M3 and M4, and the F06, F12, and F13 M6). Last year, we examined how this ‘box has become a darling of the tuner scene, able to handle serious power figures while shifting in just 50 milliseconds flat.
It sounds like the perfect transmission to throw behind a massive 8.4-liter V10 engine with forced induction to boot. Indeed, the result is a steroidal American snake that shifts like the European exotics of today.
As reported by Road and Track, the build is the work of Carma Performance. The twin-clutch Viper has been shown off in videos by shop owner Erin Carpenter, who jumped behind the wheel to put the machine through its paces, as seen in the video above. Armed with a supercharger setup from Procharger, it’s making somewhere in the realm of 1,200 horsepower. Gripping the sequential stick as the Viper surges, Carpenter slams through the gears in the blink of an eye.
The gearbox for this build was lifted from a F10 BMW M5. “The reason we like the F10-generation box is because it’s a long ratio box, and I just felt like that was probably better suited for a car that was going to be driven on the street,” Carpenter told Road and Track.
The swap naturally took a great deal of work. It required fabricating an adapter plate to bolt the transmission to the Viper V10, as well as a custom driveshaft to send drive to the rear end.
Beyond the mechanicals, there were some electronic problems to solve, too. These dual-clutch boxes are all computer-controlled, and they expect to speak to a network of BMW computers from the original vehicle they were installed in. When you yank the transmission out and throw it in a Viper, all of those computers are gone, and the transmission generally doesn’t like that.
“It was a huge pain in the ass,” Carpenter told Road and Track. “We kept the factory [transmission control module] inside of the transmission, and then we’re using a computer from a company called Maxx ECU that is basically spoofing the factory transmission control module into thinking it’s still in the F10.” MaxxECU sells its custom DCT controllers to enable the transmission to work in a wide range of swap applications. Without an aftermarket controller talking to the transmission and feeding it with the necessary speed, RPM, and other signals, the dual clutch would simply fail to function.
As you might expect, a lot of tuning and tweaking goes into a swap like this. “I probably have dozens and dozens of hours of laptop time just driving around [and] tuning, in order to get it happy,” Carpenter told the outlet. The Viper is set up to manage the amount of boost per gear. The full 1,200 horsepower isn’t available until third gear, helping make launches safer and the car more controllable.
The build isn’t complete just yet. There’s still work to be done to tune the transmission’s automatic mode to suit the Viper’s power delivery. It’s part of the benefit of the dual-clutch swap. Done right, you can have a great deal of manual control, and you can also let the ‘box row the gears for you when you’re just cruising around. For now, it also remains a one-off—Carpenter isn’t sure if Carma Performance will offer the swap on an ongoing basis to more customers. Carpenter estimated jobs like this one would land around the $15,000 to $20,000 range, no surprise given the amount of work involved.
It’s easy to see the appeal of a dual-clutch swap in a build like this. These are readily available performance transmissions that are relatively straightforward to work with and handle an absolute boatload of power. Besides, if you want to make a Viper much faster around a race track, faster shifts are a great way to do it. While you lose the romance of shifting your own gears, you do get that thrill ride acceleration that only a rapid-fire dual-clutch can provide. If you’ve got a ridiculous yearning for that modern supercar feel in a roaring American bruiser… this is exactly how to do it.
Read the full piece over at Road & Track; we figured we’d share it since we’d previously written about the glory of the Getrag GS7D36SG in our article “Here’s Why Geniuses Are Swapping BMW Transmissions Into Everything From Muscle Cars To S2000s.” Turns out, we’re not totally full of it!
Image credits: Dodge, Maxx ECU
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