Sno Stuff Rumble Pack on Viper

J

jholden

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Dec 26, 2007
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79
Age
49
Location
Byron, MN
Has anyone checked to dB on the Sno Stuff Rumble Packs for the Vipers. I think I want one, but am concerned about the sound level restrictions in Wisconsin and Michigan. Are they too loud???
 
yes. I heard one on a 05 f7 loud is an understatement. I've got an slp and the sound is great. even though everyone says you lose 1 or 2 hp.
 
yep..they all lose power. That's why I won't run one. I'd be happy if it ran the same as stock, lost some weight and sounded better, but I haven't found one to accomplish this. I tested the Bender, SLP and MBRP all in one day in the field testing it against another Viper. The power loss was staggering to say the least. I went from running almost even to the other Viper to getting smoked by half of the test strip (about 1000' runs) The MBRP was the worst and the SLP and Bender were better but still dropping about 5-7 lengths in that distance of runs. It's kind of strange because I have tested SRX's , SX700's and SX600 twins with cans and have never seen power losses like this.
 
I had one on my Viper, nice sound, I did do an A-B Comparisonn with the stock silencer with a dB meter, and found maybe a 1 dB increase around 6-7000 RPM. Very trail friendly on the viper. I did not notice any top speed reduction or power loss, but no gain either. It is significanly lighter, and makes it much easier to check chaincase oil. Fit and finish was great, and when I removed it after 3 seasons (wifes sled now, she did not like the tone) it looked new. I thought the sound was great, I think you can get youtube clips if you look.
 
Thanks guys. I checked on youtube, but it's difficult to really get a feel for how loud they are. It seems like the rumble packs on the SX 700's are much louder than stock, but it was tough to tell on the viper vids. I was just afraid that when I take this sled out to Wisconsin and Michigan that I would have to remove it because of the noise laws. I don't need a ticket or want to hear the exhaust rumbling in my sleep after a long day. It seems as the searching that I've done that these things pretty close to stock with a nice growl.
 
Bigsur said:
I had one on my Viper, nice sound, I did do an A-B Comparisonn with the stock silencer with a dB meter, and found maybe a 1 dB increase around 6-7000 RPM. Very trail friendly on the viper. I did not notice any top speed reduction or power loss, but no gain either. It is significanly lighter, and makes it much easier to check chaincase oil. Fit and finish was great, and when I removed it after 3 seasons (wifes sled now, she did not like the tone) it looked new. I thought the sound was great, I think you can get youtube clips if you look.
Click to expand...

You probably won't notice the power loss until you do a real world comparison against another sled like I did. That is the only way I can justify any of this stuff.
 
jholden said:
Thanks guys. I checked on youtube, but it's difficult to really get a feel for how loud they are. It seems like the rumble packs on the SX 700's are much louder than stock, but it was tough to tell on the viper vids. I was just afraid that when I take this sled out to Wisconsin and Michigan that I would have to remove it because of the noise laws. I don't need a ticket or want to hear the exhaust rumbling in my sleep after a long day. It seems as the searching that I've done that these things pretty close to stock with a nice growl.
Click to expand...

Of the ones I tried the SLP was very quiet.
 
If you go to WI with a can, you will get a ticket. I did and It was $160.00 dollars on the spot. They have an uplink and can run your credit card right on the trail. Makes a loud can real expensive.
 
New York has restrictions, basically you can have a modified (aftermarket) exhaust, but it can't be any louder then stock. I was never pulled over for my rumble pack, but did have a few police checkpoints where the officers checked it out. I always carried a print-out of an excel spreadsheet I made comparing the dB's of the stock and aftermarket exhaust, along with the SAE testing spec and the NYS law regarding snowmobile exhausts. After showing to the officers, they let me go without any further questioning. The rumble pack really is not any louder then stock, just has a different tone. Early triple pipe ZRT's and the like are MUCH louder stock. If you live in a state where they have sound laws, know the law and be prepared to "defend" yourself.... just my $.02....
 
New York State Finance Law Article 6, Title D, Article 25.17e. . Here is a what it says:

(e) Mufflers. An adequate muffler system in good working condition. On
and after June first, nineteen seventy-two, no snowmobile manufactured
after June first, nineteen seventy-two shall be sold or offered for sale
unless it is equipped in such a way as to limit noise produced by the
snowmobile to not more than eighty-two decibels as measured on the "A"
scale at fifty feet. On and after June first, nineteen seventy-five, no
such snowmobile manufactured after June first, nineteen seventy-five
shall be sold or offered for sale unless it is equipped in such a way as
to limit noise produced by the snowmobile to not more than seventy-eight
decibels on such scale. On and after June first, nineteen eighty, no
such snowmobile manufactured after June first, nineteen eighty, shall be
sold or offered for sale unless it is equipped in such a way as to limit
noise produced by the snowmobile to not more than seventy-three decibels
on such scale. Should the federal government adopt snowmobile noise
level standards different from those contained in this paragraph and
require that the state conform thereto, the commissioner shall be
authorized to adopt rules and regulations superseding the noise level
requirements of this paragraph to achieve compliance with federal
standards. No snowmobile shall be modified by any person in any manner
that shall amplify or otherwise increase total noise emission to a level
greater than that emitted by the snowmobile as originally constructed,
regardless of date of manufacture.
 
I just read the article in the JAN 09 American Snowmobiler about installing a Speedwerx silencer on the 1000 Cat twin. We all know these silencers lose weight and sound different but what got me was the other statement. They mentioned that SOME mfgs. claim a HP gain, but in reality they had only found in ONE instance that any silencer on a given sled actually made HP and they couldn't figure out why. They did not say what brand or model machine this was on.....but it made me wonder.How many of them have they tested on sleds that they LOST HP?? That part they don't want to tell you about.
 
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