Snowmobile Vehicle

Independent researchers are also working on the air pollution issue. Even undergraduate and graduate students are participating in contests to lessen the impact of emissions from snowmobiles. The Clean Snow Mobile Challenge is held yearly at Michigan Tech University regrouping the entries from universities from across United States and Canada. Some of the participants in recent years have been the École polytechnique de Montréal with a quasiturbine engine and students from École de technologie supérieure of the UQAM with a less polluting two-stroke engine using E85 and direct injection.
• Noise
Maximum noise restrictions have been enacted by law for both production snowmobiles and aftermarket components. For instance, in Quebec (Canada) noise levels have to be 78 decibels or less at 20 meters from a snowmobile path. Now in 2009, snowmobiles produce 90% less noise than in the 1960s. However, noise has cumulative effects on users and people living near those trails that are not well researched. It is still the origin of numerous complaints. Efforts in regard to noise reduction have now generally shifted to suppressing mechanical noise of the suspension components and tracks. Arctic Cat in 2005 introduced "Silent Track technology" on touring models such as the T660 Turbo, And Bearcat. Some M-Series sleds also had this. Ski-doo has since then also used comparative "silent track technology" on some production models.
A common dispute among the snowmobile community is about the use of aftermarket exhaust systems, commonly known as "cans" or "silencers". These replace the stock muffler with a less restrictive system that is usually claimed to increase power output of the engine. However, these aftermarket exhausts are often much louder than stock, with some being only slightly quieter than a completely open, unbaffled system. Most, if not all local snowmobile clubs(that maintain and groom trail systems) discourage the use of these systems due to landowner complaints about their noise and subsequent revoking of trail use rights through their property. Local and state authorities have been setting up checkpoints on high traffic trails, checking for excessively loud systems and issuing citations when found. Typically these systems are installed on 2 stroke powered machines(giving the distinctive "braap" sound), however in recent years aftermarket companies have released silencers for 4 stroke models as well. But louder is always better right?