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So why did Ski-Doo not go all the way and make a one-piece crank with a split center bearing? My guess is they like the center worm gear drive that runs the water pump. Locating the water pump on the outside by the starter housing would probably have made the engine three inches wider and two pounds heavier. The piston is forged, but it has a steel insert as a ring carrier. This diesel technology ups durability by providing a much harder surface for the rings to “hammer” against, something that usually wears out aluminum ring grooves faster.
The bore surface in the cylinder is also now coated with plasma-sprayed iron powder. The advantage is a steel running surface that is more porous than Nickel-Silica coating to hold a better oil film, but with much better heat transfer than a thicker steel sleeve. This is also well-proven technology, but more expensive than Nikasil coating. There is also room for expansion with this design. With an 82mm bore and a longer 80mm stroke, just a small increase in bore by 2.5mm will up the displacement to 900cc.
The E-TEC injection system is now in its second generation with a major redesign. The injector housings are now one pound lighter than the 800 E-TEC and managed with greater precision. The new engine management electronic is twice as fast as the E-TEC 800 (32 million cycles per second). In addition, Rotax added one regular injector in each throttle body to improve acceleration. Think of them acting as accelerator pumps in a carb.
AmSnow associate editor Ross Halvorson, who had a chance to try the new sled at the introduction in Quebec, reported amazing response at any speed and throttle position, which combined with the new primary roller clutch made it not only very quick, but also very smooth. You can read the rest of his early ride impressions
here.
Additional features are three-way power valves (which react three times faster than the 800 E-TEC), a smaller three-chamber muffler and a better flowing and quieter air box with separate tuning chambers that match dominant frequencies.
Even with these gains in power, torque and response, fuel consumption remains at 19 mpg, while oil consumption has been reduced by 40%.