Factory two-stroke turbo became a reality for the first time today when Ski-Doo launched a 2020.5 Summit 850 E-TEC Turbo snowmobile, with an engine that offers varying levels of boost and up to a claimed 40 hp increase in power at 8000 feet of altitude and above, meaning its affects will be felt most in the thin air where Summits are intended to be ridden.
It’s a breakthrough moment – both for snowmobiles and for two-stroke engines in general – as it’s the first-known factory turbo on a mass-produced two-stroke powerplant. And, since it’s factory built, it comes with a warranty, meets emissions standards and has an original equipment manufacturer (OEM) level of testing and development.
The 850 E-TEC Turbo also features a unique setup: At sea-level, the turbo does little. However, once the engine and ECU start sensing altitude the exhaust is bypassed through a turbine that creates boost that is then dumped into the cylinders – with the ultimate goal being to keep the engine at 165 horsepower, despite a diminishing level of oxygen that normally robs 3 percent of available horsepower for each 1,000 feet of gained altitude.
So, according to Ski-Doo, a naturally aspirated (N/A) engine that creates 165 hp at sea level would normally only create 125 hp at 8000 feet, but with the turbo it still produces 165 ponies. And, it creates a consistent 165 horsepower at 6200 feet (while an N/A engine would produce 138) and at 3000 feet (vs. 150 on an N/A setup), for example, thanks to its varying level of boost. Maximum boost pressure is 4 pounds per square inch (PSI), Ski-Doo official said. Above 8000 feet, it maxes out at 40 added horsepower, so at 10,000 feet, where a 165 N/A engine would create 115 hp, the 850 E-TEC Turbo makes 155.
The machine on which it’s found is not labeled an Expert, X, SP or Sport but merely as a Summit 850 E-TEC Turbo. That said, it features many components from the new-for-2020 Expert package, including but not limited to the short tunnel, tiny snowflap, lightweight spindle, revised ski stopper, remote-adjustable limiter strap, lightweight springs and tapered handlebar. From the X package, though, it has a HPG Plus shock on the rear arm of the tMotion skid (as opposed to KYB Pro 36 on the Expert) and a different seat (deep snow compact vs. Forty7C on the Expert).
It will also come standard with the push-button, hot-restarting system called SHOT.
Our own TJ Krob was at today’s unveiling and came away super enthused, gushing over the phone to us about the power that was available at the test site outside of West Yellowstone, Montana.
“Man, this thing rides like a dream,” Krob said. “It is sewing-machine smooth, and the way they positioned the turbo up high in the middle, I swear this machine is balanced better than a naturally aspirated Summit.”
Krob also talked about how consistent the power hit was.
“It’s useful power — it never feels like it’s trying to get out from under you or being real peaky like many aftermarket turbos,” Krob said over the phone right after returning from the ride. “It’s the perfect, elegant solution to maintaining power as altitude would normally make it decline.”
In speaking with Ski-Doo officials, Krob learned that adding a turbo was a part of the original design goals for the 850 E-TEC engine that was unveiled for model year 2017. Plus, the turbo is different that the one found on four-stroke Rotax products, including the 900 ACE Turbo snowmobiles.
Click on either video in this layout to get some of TJ’s reactions.
The Summit 850 E-TEC Turbo will be built in limited quantity for this winter, with orders being taken by dealers the next couple of days and shipping of the already-built units starting this Thursday, January 16. That said, history tells us a more full-build will be a part of the 2021 lineup. These early machines won’t come cheap, though: MSRP will be $18,099, and you can bet dealers won’t be discounting this first pilot build! In fact, we’d expect most will sell at prices higher than the MSRP.
Ski-Doo officials say their factory turbo has no lag, thanks to a short intake and smart design that includes ball bearings for quick spooling speeds. An electronic wastegate is controlled by the ECU to provide the varying levels of boost.
Compared to adding an aftermarket turbo, Ski-Doo claims their design offers a factory warranty and features a design optimized for the engine and the chassis in which it sits. Also, Ski-Doo says its design is about half of the weight of aftermarket options. And, it runs on pump gas — Ski-Doo officials stressed the design was created with simplicity and rider piece-of-mind at its core.
Below is the full press release from Ski-Doo
2020 SKI-DOO SUMMIT 850 E-TEC TURBO
The Ski-Doo Summit 850 E-TEC Turbo is a snowmobile that completely redefines high elevation riding and takes the industry to new heights. Riders will experience factory-built power in a way never before attainable until the Summit 850 E-TEC Turbo. Riders also get never before seen manufacturer-backed ease of use and peace of mind – because this is the world’s FIRST EVER OEM-built 2-stroke turbo engine.
The high elevation experience gets easier and more fun as deep snow pilots get the same kind of power their low elevation comrades have had for years, with no turbo lag and the same renowned ultra-quick throttle response Rotax 850 E-TEC engines are famous for. The first ever factory produced 2-stroke turbo also lets riders enjoy centrally balanced handling, lighter weight and consistent performance, as altitude increases. Peace of mind is part of the package too with perfect factory integration, accurate calibration at all altitudes, in all conditions and the reassurance of a factory warranty.
Riders will enjoy every ounce of the 165 horsepower from the industry’s leading 2-stroke engine to its fullest, all the way to 8,000 feet (2438 m) in altitude. They continue to enjoy a 40-hp advantage over non-turbo 850’s from there up on the way to discovering stunning new winter playgrounds.
This 2020 late release Ski-Doo model begins with the REV Gen4 platform. So responsive, a simple glance is all it takes to point it in the rider’s desired direction. There’s no deep-snow snowmobile that translates the relationship between rider, sled and epic terrain better than the Summit.
More than a new engine, it’s a complete lightweight, turbocharged package fully designed by Rotax and Ski-Doo. In addition to delivering all its power at less weight than aftermarket turbo kits, the optimized layout in the chassis keeps the sled balanced side to side for easier handling. Available at dealers now, the Summit 850 E-TEC Turbo also comes standard with a new one-piece lightweight hood.
Highlights of Summit 850 E-TEC Turbo
- Rotax designed and built turbocharged engine
- First mass production 2-stroke turbocharged engine in any vehicle
- 165 horsepower up 8000 feet (2438 m) elevation, +40 horsepower over normally aspirated 850 E-TEC above that
- Runs on pump gas
- Factory integration delivers balanced handling and accurate calibration
- Factory warranty
- One-piece lightweight hood
- Available at authorized Ski-Doo dealers now
Technology background for Rotax 850 E-TEC Turbo
Designed specifically for the 850 E-TEC entirely within Rotax walls, the new turbo ensures full use of the 850 E-TEC’s 165 horsepower all the way up to 8000 feet and then maintains a significant 40-horsepower advantage over normally aspirated engines from 8000 feet to the top of any mountain
When designing the new 850 E-TEC Turbo engine, four key factors were front and center for Rotax and Ski-Doo engineers to ensure optimal consumer satisfaction:
- Responsive power delivery with no lag,
- light weight
- and seamless integration into the responsive REV Gen4 platform.
Optimizing power at minimal boost was critical for both throttle response and longevity. An intake with a short-track bypass tract keeps throttle response crisp and quick, while the streamlined exhaust system minimizes backpressure.
An electronically controlled wastegate maintains consistent boost pressure (up to 4 PSI) and delivers it precisely as needed, to ensure the dynamic performance characteristics of the 850 E-TEC are never lost.
The inhouse Ski-Doo/Rotax design advantages are immediately felt when riders experience how flawlessly the turbo package performs from idle to wide open throttle and how it integrates with the rest of the snowmobile. The compact turbine and compressor are ideally fitted within the REV Gen4 chassis. The lightweight material along with a patented lightweight continuous oiling system and optimized down pipe are laid out to ensure the entire powerpack stays centrally balanced within the frame.
It’s all wrapped in a new one-piece lightweight hood and unique side panel with strategically placed venting for optimal cooling of critical power-producing components, and sleek, sexy styling.
Editor’s Note: This review was originally published in the October 2020 issue of Snow Goer. Every issue of Snow Goer magazine includes in-depth sled reports and comparisons, aftermarket gear and accessories reviews, riding destination articles, do-it-yourself repair information, snowmobile technology and more! Subscribe to Snow Goer now to receive issues delivered to your door or your computer for a low cost.