If you operate a snowmobile for recreational, professional, or transportation purposes, you may wonder why they are so loud? It’s necessary to examine how aftermarket parts, engine tuning, and engine type determine a sled’s decibel output.
Why are snowmobiles so loud? Although today’s models produce less noise than sleds made before 1975, snowmobiles with aftermarket parts, modifications, or 2 stroke engines will produce more sound. Several jurisdictions across the country prohibit loud vehicles with exhaust modifications.
Snowmobiling is an exhilarating way to travel. The performance and efficiency of today’s snowmobiles are far superior to models produced before 1969. They are safer, more maneuverable, and for the most part, quieter than early models. However, many states adopted strict decibel guidelines for winter sledding. In the early 2000s, a previous ban on snowmobiling in state and national parks was lifted, and riders crowded the trails. When riders modify their sleds to increase performance and lower weight, they often increase the decibel output and incur fines from authorities.
Early snowmobiles were extremely loud and dangerous vehicles. From fifty feet away and traveling at full throttle, old sleds could produce decibel readings as high as 102dB. Current models, without modifications and moving at the same distance, produce 78dB or less. (source)
Today’s snowmobiles are complex machines. The stock components are tuned to work in perfect coordination with the vehicle’s engine. If you install a new muffler without modifying the engine, you run a risk of damaging it and tormenting nearby residents with deafening noise.
The stock exhaust systems for modern snowmobiles are designed to meet federal requirements for noise pollution. Current Models must only emit 78dB from fifty feet away. Although most riders and clubs adhere to the rules, some feel limited by the performance of stock parts and choose to modify their sleds.
While most snowmobilers try to follow their local guidelines for decibel levels, some riders flaunt their loud engines and continuously fiddle with the machine to increase the noise. Some riders replace their stock mufflers with an aftermarket part like this one. You can increase the overall top speed of a sled by replacing the muffler, but this often results in louder exhaust sounds.
If you’d like to view a video of a snowmobiler who purposely modified his sled to make it louder, check the video below. Just a warning, you should turn your sound down before watching it because it is extremely loud. The “mountain can” exhaust modification the rider uses produces a high-pitched, ear-splitting scream that you hear echoing through the mountains.
Throughout the country, park rangers and local police increased their enforcement of noise restrictions on public trails. Residents and hikers frequently criticize snowmobiles for their noise. After increased complaints, some authorities restricted or banned vehicle access to trails.
Environmental groups continue to argue with snowmobile clubs over which trails are suitable for vehicles. The biggest issue in the debate is the legality of using aftermarket parts that boost RPMs and increase performance.
Until the beginning of the twenty-first century, nearly all snowmobile manufacturers used two-stroke engines in their vehicles.
When environmental groups or government agencies suggested to snowmobile companies that they switch to a four-stroke design, the companies responded that four-stroke engines were too heavy and cumbersome to power a snowmobile.
With advances in engine and exhaust designs, engineers eventually adopted an efficient four-stroke engine for snowmobiles. Two-stroke engines are significantly louder and less efficient than four-stroke models. For an idea of how the noise output of various engine types vary, examine the following chart. (source)
|Vehicle||20.5 mph||36.04 mph||46.6 mph||Full Throttle||Idle|
|2-Stroke Model Average||70.7 dB||73.9 dB||75.3 dB||78.7 dB||55.4 dB|
|Artic Cat 660||65.8 dB||72.0 dB||72.3 dB||71.6 dB||42.1 dB|
|Polaris Frontier||65.6 dB||71.2 dB||72.6 dB||74 dB||51.4 dB|
Although the four-stroke models are gaining popularity with professional racers and recreational riders, some enthusiasts prefer the louder two-stroke models. There are more aftermarket parts available to soup up two-stroke vehicles.
Another reason some choose a two-stroke model is the price. Four-stroke engines are much more expensive and less appealing to amateur riders.
Like the gearheads who tinker with their hot rods, many snowmobilers enjoy modifying their sled’s engines to boost performance. Adjustments to the engine and exhaust system can improve a sled’s acceleration and top speed, but if performed incorrectly, you can damage or destroy an expensive engine.
You should only attempt installations or repairs if you have several years of experience with snowmobile engines. Whether you modify it yourself or pay for professional help, the biggest problem with upgrading your sled’s horsepower and RPMs is the resulting increase in noise.
Like most internal combustion engines, the faster it goes, the more noise it will make. Installing a homemade muffler or silencer to counteract a loud engine often has the reverse effect. Some shoddy modifications increase the decibel level and may decrease the engine’s longevity.
To ensure that your enhancements will not damage your snowmobile, only hire a mechanic who’s familiar with your sled’s make and model.
Since bad apples spoil the fun for the whole bunch, many snowmobile clubs require members to follow strict guidelines under the penalty of expulsion. Riders who tear through the trails at full throttle and disregard the area’s decibel restrictions give the sport a bad reputation.
There is a significant difference in noise output when you compare an engine’s idle speed and its top speed. Among both two-stroke and four-stroke models, the difference ranges from twenty to twenty-five decibels. Most trails have a posted speed limits for riders to follow, and some prohibit full-throttle racing.
Another crucial factor in controlling sled noise is the distance between riders and civilians. Well- designed trails that allow snowmobiling have posted warnings to keep riders from getting too close to private property or hiking trails.
Most snowmobilers must stay anywhere from fifty to one hundred feet from private property.
Without modifications, most two-stroke and four-stroke snowmobiles traveling at full throttle emit 78 dB of sound or less at fifty feet. The vintage models from the 1960s and 1970s produced anywhere from 102 to 110 dB at the same distance.
However, these decibel readings were challenged in 2004 by Yellowstone National Park rangers who performed their own study. They disputed the federal government’s assurances that modern four-stroke engines were much quieter and would not negatively impact the environment or the well-being of parkgoers.
After recording vehicles that produced 111 dB, the rangers warned their employees who rode four-stroke models that the sleds were not noticeably quieter than two-stroke models. They insisted that anyone riding a sled needed ear protection since the vehicles’ sound output exceeded doctor recommendations for safe noise levels.
It’s unclear whether the rangers’ tests included vehicles with or without modifications, but it’s safe to say that the average noise produced by a snowmobile lies between 78dB and 100dB.
The engine type, modification level, and speed aren’t the only factors that influence a sled’s noise level. The distance has a lot to do with the noise level, and if a rider is close by, the noise is more intense.
One way that trail planners reduce the noise effects caused by sleds is to incorporate sound barriers into their trails. The following is a list of natural and man-made barriers planners use to reduce noise.
A trail flanked by sound barriers helps reduce noise pollution and contributes to fewer complaints from hikers and nearby residents. Posted speed limits and proximity warnings also help to lower trail noise.
When a trail is properly designed, the noise from snowmobiles becomes less of an issue. Poorly conceived pathways that don’t include sound barriers or speed limits infuriate locals. When public outcry reaches a certain point, authorities can close the trail and prohibit snowmobiling.
Snowmobile makers are producing vehicles that are quieter and more energy-efficient than previous models, but their focus has not been noise reduction. One company, Taiga Motors, takes a different approach to snowmobile design.
Taiga produces an all-electric snowmobile that’s capable of traveling from 0 to 60 mph in three seconds. The vehicle is the only electric sled on the market, and no other snowmobile can compete with its quiet engine or zero-emissions technology.
The Taiga sleds are the future of the sport and will likely please environmentalists and mountain residents. If you’d like to see a Taiga in one of its early runs, take a look at this video.
Although improvements in automotive technology have led to quieter snowmobiles, noisy sleds continue to draw complaints from environmentalists, hikers, and residents.
The use of aftermarket modifications is the most significant point of contention, and some municipalities and snowmobile clubs outlawed their use due to mounting criticism.
If your sled violates decibel levels on public trails, your best option is to seek permission to ride from a private landowner. You can crank your snowmobile up to full throttle without worrying about noise levels or speed limits.
Have fun but beware of avalanches.
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