Last spring, while most of the Midwest snowmobiling scene was winding down for summer, Jim Czekala at DynoTech Research was hard at work dynoing more than one pre-production 2009 600 E-TEC engine.AmSnow
test riders also got some saddle time on a pre-production 600 E-TEC last spring on top of the time at industry product unveilings. We knew how it felt, but were curious to see what Jim's power numbers would be. Mind you, these were pre-production models so things may change by the time these sleds start rolling off the line in early fall. At the time this article was written, these were the latest numbers anywhere.Ski-Doo vs. Ski-Doo vs. Ski-Doo
After dynoing several 600 E-TECs, Jim found they made about 117 hp at 8,100 rpm (116.7 hp to be exact). Jim did more than a dozen full throttle dynos and said, "horsepower varied from 107 to 117, not in any particular order. My initial thinking after reviewing this data is that E-TEC engine airflow may decrease more with rising engine temps than we might see with carbed or conventional EFI engines."
Much of the "bench racing" talk at local watering holes and on our online forums this spring and fall has focused on the performance of the former Ski-Doo 600 SDI engine and the old 500SS vs. the new 600 E-TEC. DynoTech dynoed both the 600 SDI and E-TEC machines and found that last year's MXZ X 600 SDI in the XP chassis had 126.7 peak horsepower. So, at first glance it would look like the 600 E-TEC falls short of that engine.
However, there is a big difference between the two engines' power curves. The E-TEC powerband could almost be compared with that of a 4-stroke. Except for one small dip, it's very even across the curve. The '08 600 SDI has two big power dips in its powerband followed by its peak power. Jim also said he has heard of some '07 SDIs having detonation issues when operated at high speeds for very long periods on poor quality gas. So, perhaps the '08 ECUs were programmed with retarded timing, this would account for the powerband dips. It would make them safer, but lazy in that spot. Finally, Jim tells us, "There was a wide variation in engine output depending on engine temps on the E-TEC. We did comparisons detailing power, airflow and most importantly BSFC (brake specific fuel consumption) between the E-TEC and 600 SDI, which can all be seen online."
The new 2009 MXZ X 600 E-TEC also will compete with the MXZ TNT, which has the option of a 500SS motor. Rich Daly at DynoPort dynoed this sled for us last year and saw 114 hp at 8,000 rpm. It's safe to say that the new E-TEC will probably land somewhere between the 500SS and 600 SDI motors as far as horsepower goes.
Peak torque numbers on the E-TEC were 76 foot-pounds at 7,900 rpm. Again, this number beats the 500SS on torque, but doesn't quite match the 600 SDI.What's important
To many riders, shaving off just a little horsepower is all right, but only if the machine handles better, or gets better mileage, or is better on oil. (DynoTech's part-throttle midrange dyno data shows BSFC in the mid .40 lb/hphr range, which means it's very stingy on fuel at cruise.) Ski-Doo promises the new E-TEC will deliver all these advantages in a big way.
From our pre-production trail-testing, we can safely say that these dyno tests reflect our initial reactions to its power. The E-TEC is smooth and makes good power but doesn't have an exhilarating shot of energy anywhere in the throttle pull. It has more of a steady 4-stroke feel.
More info: www.dynotechresearch.com