Brian,
One of the primary factors for getting the E-tec was because BRP was able to offer a vastly superior snowmobile Rotax
2 cylinder 2 stroke engine that had an altitude compensating ECM that sensed barometric pressure, humidity and air temp. We had one basic main and idle jet that would compensate for altitudes from 5,000 to 12,000 and another jet for sea level to 5,000' Since these are Mikuni carbs we can still fine tune the mid-range needle jets.
The mixture is adjusted via a vacuum device attached to the float bowl which leans out the fuel as altitude/temp changes while the ECM changes engine timing according to engine loads and detonation. This system is still being use on current Rotax 600/800HO and R engines--since 2004 with subtle improvements in ECM and exhaust port RAVE valves that adjust the port exhaust for max torque.
The E-tec OB is fully altitude compensated--nothing to change or adjust except indexing the plugs.
We also did alot of oil testing and found the semi-synthetics to be the cleanest burning and lest carbon building for a cleaner internal engine. I'm sure the BRP X100 oil contributes to the lack of smell and smoke.
The guys I ride with who have the E-tec report at least a 40% better fuel range, smoother/quieter power, and vastly superior oil consumption with NO SMOKE or stink (I can attest to that since I'm always following them). They are getting 153 HP @ 8,200 rpm from their 800 and I am at 136 HP--however, my real HP at 10,000' is calculated to be 33% less--or--85 HP. I also run a 153" X 16" x 2" powder track and the best trail speed I can get is 65 MPH--kinda like a 500 Fan at sea level
So my E-tec 60 is technically only putting out 46 HP @ 5,000rpm @ 8,000' with a 9 X 14 prop getting 15 knts empty ballast on a flat lake, no wind. I think the engine runs pretty strong as I have a few Merc BF 60 dock mates to compare notes with.
Now it's time for me to start thinking snow--wait, I still have some boat winterizing yet to do
Enjoy whats left of your summer-unless you're still sailing you're probably not think'n snow
Bob