Most modern snowmobiles make use of either a four- or two-stroke internal combustion engine. Two stroke engines with reduced complexity have reduced weight and cost compared to the four stroke counterparts. However, the picture is slowly changing since the last fifteen or so years, with four stroke engines gaining quite an amount of popularity. Yamaha has also started rolling out only four-stroke snowmobiles accounting to their popularity.
What Engine Type To Consider When Buying A New Snowmobile?
Four stroke engine is great for riding on the trails. Now, it is more expensive heavy engine, but requires less maintenance and hence will also last longer. Another plus point is that you need to change oil only once in an year and so you need not worry about carrying oil with you It will require an oil change about once a year and so no need to worry about carrying oil with you.
A two stroke engine on the other hand is more affordable. It is snappier and weighs considerably less when compared to a four stroke. However, the disadvantage is that they consume more oil and also requires more maintenance. .Being lightweight, they are the best choice for mountain riding where the prime aim is to cut down the maximum possible weight for achieving that smooth transitions you may require.
Difference between four stroke and two stroke engine
Now let us get into some of the difference between two stroke and four stroke engine in terms of a more scientific outlook.
The difference between a two stroke and a four stroke engine is based on how fast the combustion cycle occurs and how many number of times the piston moves up and down during each combustion cycle.
Now, in case of a four stroke engine, the piston is set to complete two strokes during each revolution. There will be one compression stroke and one exhaust stroke, each being followed by a return stroke and the spark plugs of the system fire once every alternate revolution. Power is produced by the engine on every four strokes of the piston. There is no requirement of premixing of fuel and oil as the four stroke engines have separate oil compartment.
Let us move on to the two stroke engine. Here, the entire combustion cycle is completed with just one piston stroke. This includes a compression stroke which is then followed by the explosion of the compressed fuel. Now during the return stroke, what happens is that the exhaust is let out and a fresh fuel mixture is made to enter the cylinder. The spark plugs fire once every single revolution. Power is made to produce once every two strokes of the piston. Here we need premixing of oil and fuel.
Snowmobile brands and engines
Ski-Doo
Coming under Bombardier Recreational Products, they use the Rotax Engines in their snowmobile brands. Be it two stroke or the four stroke engines, the Rotax engines have created a stir in the industry.
BRP Rotax engines are known in the industry for optimum power delivery, good fuel and oil utilization. Overall, they offer reliable performance.
Now as customers are demanding propulsion systems giving good riding experience as well as obeying strict environmental regulations. New BRP engines for Ski-Doo fulfils both he needs. Their four stroke engine model uses a multi-port fuel injection system which contributes to an impressive and first in class cruising range of 29 miles per gallon.
Excellent combustion stability is another feature to look upon. With Lambda values of 1.1 and higher in part load, they offer good fuel efficiency.
The geometrical layout of the engine is also good which was driven by vehicle boundaries. All the engine components are installed within minimum space. For stable riding, you require a low center of gravity and so the crankshaft is put as low as possible. Another unique feature is the rear engine contour forming one wall of the tank leading to high grade integrated components in the system. The digital mock up at each stage of the process adds more value to the system design.
The engine can be start down to minus 40 degree Celsius. There are also maintenance free valve tappets and the optimized cylinder honing process leads to negligible oil consumption.
Polaris
You can feel confident control over the sled with the Polaris range of engines. The latest Patriot boost engine claims to produce more power even as you climb up the mountain peaks. The Patriot range of engines from Polaris are said to offer good durability and fuel efficiency. The throttle response offered is best in class. Offering industries best power to weight options, the engines also come up with unrivaled acceleration.
The Cleanfire range of engines from Polaris offers reliable performance with the easy start and instant acceleration. They are known for their responsiveness and best in class weight to power.
Arctic Cat
Arctic Cat is known to be the world’s fastest snowmobile manufacturer. Suzuki has been supplying engines to Arctic Cat since 1976. Arctic Cat has also entered into engine supply agreement with Yamaha. These snowmobiles are built to Yamaha specifications using Yamaha four stroke engines.
The latest 2021 Thundercat Series has the 9000- Series C-TEC4 Turbocharged Engine. This fastest snowmobile gets the biggest and the most powerful engine on the trail. The three-cylinder engine delivers max horsepower in all conditions. With ultra-quick throttle and good turbo response, they offer great performance with minimal weight. The model also offers engine braking control via an idle speed circuit. They offer engine mapping and also comes with a press forged crankshaft.
Yamaha
Yamaha is another famous snowmobile manufacturer known for its durable models of sleds. They have started creating some of the best lightweight snowmobiles since the 1980s with the introduction of Phazer. Since 2010, they have also been in partnership with Arctic Cat.
Since their first introduction back in 2002, they have made constant revisions since then improving the four-stroke engine’s performance with due consideration in weight management. To point out in particular, the Yamaha’s RX-1 engine remains a staple of its motor sleds even to this day.
Yamaha snowmobiles with their own four-stroke engines have gained popularity as the most reliable snowmobiles of all time. They display some great features like the counter shaft for greater compactness and performance and with the dry sump system, they are engineered to reduce pumping losses. The low-pressure cast upper case leads to greater engine toughness. The fuel injection system fine-tunes the feeling of the acceleration.
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