When Yamaha and Arctic Cat announced their new Viper/7000 which was to be based upon the Arctic Cat Pro Chassis with a Yamaha engine, the crew at Evolution Powersports immediately saw the high performance potential for this marriage. Arctic Cat’s excellent handling chassis combined with Yamaha’s lightweight, torquey and sweet sounding triple would be a home run – especially with boost.
The Evolution Powersports “Special Ops” division was tasked with creating a “no compromise” turbo kit for this family of vehicles from Arctic Cat and Yamaha. A brand new Yamaha Viper was purchased from Century Powersports in Stillwater, MN and shipped to the EVO facility. R&D began immediately to source the correct hardware and electronics to achieve the no compromise goal.
EVO’s technology partner TiAL Sport was consulted for the turbocharger. It needed to provide immediate turbo response at high elevation and still make big horsepower. The other big technological hurdle was to create an engine management system sophisticated enough to provide timing control and altitude compensated boost control, along with the correct fueling as altitudes and temperatures changed, yet be cost effective. The other crucial feature required was to have multi-map capability so customers would have the choice of running high boost with a mix of race and pump fuels, or modest boost on straight pump gas. This goal was accomplished with the EVO Advanced Piggyback Controller (APC).
Since this was going to be a mountain sled, the stock Viper suspension components were all switched over to Arctic Cat ProClimb components and a ProClimb tunnel was added. Rather than use the stock ProClimb rear suspension, A Kmod skid was chosen due to its adjustability and unbelievable control of the front end while climbing. Also, the ride quality is second to none. B&M Fabrication provided the “No Snow” running boards.
The kit was fabricated at the Special Ops division of Evolution Powersports/Motorsports facility in Tempe, Arizona facility and code named the “BIG CHUTE VIPER”. Initial dyno testing was completed and the results were very promising – 275 hp at 14 lbs of boost! The sled was immediately loaded onto a trailer and brought to the mountains in Steamboat Springs, Colorado for on-snow testing. The sled proved to be an animal. Throttle response was absolutely stunning. This was no doubt due to the decision EVO made to not lower the compression ratio and instead, deal with cylinder pressures through timing changes with the EVO Advanced Piggyback Controller (APC).
The Big Chute Viper was then trailered to Alpine, Wyoming to do some testing with the crew from Team Thunderstruck and Kmod. The sled ran flawlessly and conquered many climbs, but at extreme elevations, it was found that the turbo response was a little slow. This was not going to fly with the EVO team. TiAL was provided with the on snow, high elevation feedback and spec’d a different turbo with a slightly smaller A/R on the exhaust housing. The sled was sent back to Arizona to have the kit re-worked to accommodate the new turbocharger. Dyno testing and base tuning were re-verified.
The new Big Chute Viper was then loaded up and sent to back to Steamboat Springs, CO and re-tested on snow. The new turbo lit up instantly, even at 10,000+ ft. The sled was then trailered to Revelstoke, BC Canada for some late season testing, final calibrations and chute climbs. Once again, the guys & gals from Team Thunderstruck were there. Dan Bush and Matt Losey both put the sled through its paces. Everyone was extremely pleased with the running quality. There were no coughs or hiccups at any throttle position.
After riding this sled now for an entire season on boost, the EVO crew believes the Big Chute Viper/7000 is the next “Evolution” of four stroke technology both for the trail and mountains. It handles almost as easily as an 800 class sled, but with the torque and horsepower to put you over the top of just about any climb you can find. And as elevation changes, you just keep going and going making big power all the way. And now that Yamaha and Arctic Cat both have mountain sled versions of this popular and extremely durable engine package for 2015, this package is going to be extremely popular and potent in the mountains.
For more information, options and pricing contact Evolution Powersports at 970-680-3861 or visit evopowersports.com