Horsepower – Ski-Doo
The Rotax 850 has a displacement of 849cc, compared to the 800R E-Tec at 799.5cc. That helped boost the power of the 850 10 hp compared to the 800R, giving the Rotax 850 a Ski-Doo claimed 165 hp. The bore is the same between the 850 E-Tec and 800R E-Tec (82 mm) but the stroke changed. Whereas the 800R has a stroke of 75.7 mm, the 850 E-Tec stroke is 80.4 mm. The maximum engine speed is reached at 7900 rpm, which is identical for both the 800R and 850.
Ski-Doo also claims that 850 E-Tec has a 30 percent quicker throttle response compared to the 800R.