A two-stroke snowmobile is lighter for the same power, while a four-stroke runs on regular fuel in its non-turbo versions and is the only engine type among 2027 models on Yellowstone's approved list. On the same 2027 Ski-Doo Renegade package, the 600RR E-TEC two-stroke weighs 50 lb less than the 900 ACE Turbo four-stroke at the same 130 hp.
| 2027 Renegade Adrenaline with Enduro Package engine | Engine type | Horsepower | Dry weight |
|---|
| Rotax 600RR E-TEC | Two-stroke | 130 | 505 lb |
| Rotax 850 E-TEC | Two-stroke | 165 | 514 lb |
| Rotax 900 ACE | Four-stroke | 95 | 529 lb |
| Rotax 900 ACE Turbo | Four-stroke, turbo | 130 | 555 lb |
| Rotax 900 ACE Turbo R | Four-stroke, turbo | 180 | 559 lb |
Figures are Ski-Doo's own 2027 US specifications, read on 27 October 2026. Horsepower is Ski-Doo's rating from the model specifications; Ski-Doo's separate engine overview page gives 125 hp for the 600RR E-TEC. Dry weight excludes fuel and fluids. The package starts at $16,649 MSRP, which excludes transportation and preparation; Ski-Doo does not show a separate price for each engine on the model page. Browse snowmobiles for sale on Searchshop to see what dealers near you have in stock.
The comparison uses published manufacturer and park service data, not test rides. Ski-Doo's 2027 US model pages list dry weight, horsepower, fuel grade and oil tank size for two-stroke and four-stroke engines in the same package, so the same chassis can be compared with only the engine changing. Those pages, Ski-Doo's Rotax engine page and Yellowstone National Park's snowmobile rules were read on 27 October 2026.
Four packages offer both engine types: the Renegade Adrenaline with Enduro Package, which Ski-Doo calls the only Renegade with both two-stroke and four-stroke engine options, and the Expedition Sport, Expedition LE and Expedition Xtreme. Fuel economy is quoted only where Ski-Doo publishes a figure, and those figures come from Ski-Doo's own testing.
Two-stroke engines make the same sled lighter in each 2027 Ski-Doo package compared here. On the Renegade Adrenaline with Enduro Package, the 600RR E-TEC two-stroke weighs 505 lb and the 900 ACE Turbo four-stroke weighs 555 lb, with Ski-Doo rating both at 130 hp. The 165 hp 850 E-TEC two-stroke, at 514 lb, is still 15 lb lighter than the 95 hp 900 ACE four-stroke.
| 2027 Ski-Doo package and engine | Engine type | Horsepower | Dry weight |
|---|
| Expedition Sport 600 EFI | Two-stroke | 85 | 504 lb |
| Expedition Sport 600 ACE | Four-stroke | 62 | 527 lb |
| Expedition Sport 900 ACE | Four-stroke | 95 | 549 lb |
| Expedition Xtreme 850 E-TEC | Two-stroke | 165 | 590 lb |
| Expedition Xtreme 900 ACE Turbo R | Four-stroke, turbo | 180 | 621 lb |
The Expedition Sport starts at $10,849 and the Expedition Xtreme at $17,249, before transportation and preparation. On the Expedition Sport, the 600 EFI two-stroke is 23 lb lighter than the 600 ACE four-stroke and rated 23 hp higher. On the Expedition Xtreme, the 850 E-TEC is 31 lb lighter than the 900 ACE Turbo R.
The Expedition LE follows the same pattern: with a 16-inch track, Ski-Doo lists the 600RR E-TEC two-stroke at 528 lb and the 900 ACE four-stroke at 552 lb.
The non-turbo four-strokes are the only 2027 Ski-Doo engines in these packages that run on regular 87-octane fuel. Ski-Doo lists premium 91-octane fuel for every two-stroke in the comparison, including the entry 600 EFI, and for the turbocharged 900 ACE Turbo and Turbo R four-strokes.
Ski-Doo says the Rotax 600 ACE gets up to 28 mpg, based on its own engineering trail testing on an MXZ, and calls it the industry fuel economy leader. It quotes up to 21.8 mpg for the 900 ACE. Ski-Doo does not publish a matching mpg figure for its two-strokes on the same page, so a like-for-like fuel cost comparison is not possible from manufacturer data.
Both engine types have an oil tank on Ski-Doo's spec sheets: 3.4 L (3.6 qt) on the E-TEC and 600 EFI two-strokes and 3.3 L (3.5 qt) on the 900 ACE four-strokes and 2.1 L (2.2 qt) on the 600 ACE. A two-stroke burns its oil as it runs, so the tank needs topping up as you ride; Ski-Doo says its engineers cut the 600RR E-TEC's oil consumption by 20%. Ski-Doo describes its ACE four-strokes as ultra-low maintenance. Follow the service schedule in the owner's manual for the sled you buy.
Emissions and noise decide where you can ride in at least one major destination: Yellowstone National Park admits only snowmobiles on its Best Available Technology (BAT) list. The park requires each sled to run at or below 67 dBA (a model's mean, with no single measurement above 69 dBA) and to be certified at no more than 15 g/kW-hr of hydrocarbons and 90 g/kW-hr of carbon monoxide. For comparison, the park lists an average non-BAT two-stroke at 150 g/kW-hr of hydrocarbons, 400 g/kW-hr of carbon monoxide and 78 dBA.
Every 2027 model on the Yellowstone approved list is a Ski-Doo with a Rotax ACE engine, which Ski-Doo lists as a four-stroke: the Grand Touring Sport 600 ACE, Grand Touring LE 900 ACE, Grand Touring Sport 900 ACE, Expedition LE 900 ACE, Expedition SE 900 ACE and Skandic LE 900 ACE. The 2026 list also includes two Polaris ProStar S4 models, the Indy Adventure 137 and Voyageur 146. Electric snowmobiles are not currently approved. If a Yellowstone trip is part of your plan, check the park's list for the exact model and year before you buy.
Ski-Doo's own 2027 lineup shows where each engine type is aimed: two-strokes for deep snow and performance trail riding, four-strokes for long-distance trail sleds. Every package on Ski-Doo's 2027 Summit deep-snow page and its Backcountry crossover page uses a two-stroke engine. The lightest listed Summit, the Summit X with the 850 E-TEC and 154-inch track, weighs 428 lb dry.
Ski-Doo describes the MXZ trail sled as built around two-stroke engines and the Renegade as built for long-distance four-stroke performance. For sleds built to carry a passenger, our guide to the best two-up snowmobiles compares the 2027 touring models. For more on how trail, crossover and mountain sleds differ, see trail vs. crossover vs. mountain snowmobiles.
The right engine depends on where you ride and how far you go in a day. Use these questions to narrow it down:
- Do you ride deep snow, mountains or tight trees? A two-stroke gives you the lighter sled, and Ski-Doo's 2027 Summit and Backcountry packages are two-stroke only.
- Do you ride long groomed-trail days or carry a passenger? A four-stroke trail or touring sled fits, and the non-turbo ACE engines run on regular fuel.
- Do you plan to ride in Yellowstone? Buy a model and year on the park's approved list; every 2027 model on it is a four-stroke.
- Is the lowest running cost the priority? Compare the 600 ACE or 900 ACE, the engines Ski-Doo publishes fuel economy figures for.
Before you buy, ask the dealer for the out-the-door price of each engine option, since Ski-Doo's model pages show only a starting price for each package. If you are shopping used, the used snowmobile buying guide covers what to inspect, and the snowmobile maintenance guide covers seasonal service. When you know which engine type fits, compare two-stroke and four-stroke snowmobiles for sale on Searchshop.
Neither is better for every rider; the right choice depends on where you ride. In Ski-Doo's 2027 specifications the two-stroke is the lighter option in each package that offers both, and Ski-Doo's deep-snow Summit sleds are two-stroke only. Four-strokes suit long trail days, and the non-turbo versions run on regular 87-octane fuel. On the 2027 Renegade Adrenaline with Enduro Package, the 130 hp two-stroke weighs 50 lb less than the 130 hp four-stroke.
There is no confirmed answer, because this comparison found no manufacturer or agency data that compares failure rates of the two engine types. Ski-Doo markets both as dependable: it describes its ACE four-strokes as ultra-low maintenance and its 600RR E-TEC two-stroke as keeping its reputation for reliability. For a used sled, the service history and condition of the individual machine matter more than the engine type.
Not on a 2027 model: Yellowstone admits only snowmobiles on its Best Available Technology list, and every 2027 model on that list is a Ski-Doo with a Rotax ACE four-stroke. Approved sleds must run at or below 67 dBA and meet the park's hydrocarbon and carbon monoxide limits. Check the park's list for your exact model and year before planning a trip.
