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Exhaust Decibel Levels, and the law....

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Old 05-11-2009, 07:28 AM   #1
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Default Exhaust Decibel Levels, and the law....

Ok so idk about where you guys are from, but the local cops around me LOOVE to pull cars over for there exhaust being too loud. especially Honda's...I actually had a cop tell me my exhaust sounded like "****". When he turned around when i was sitting at a red light and followed me and i never went over 3k rpms....I honestly said to him, "Are you serious sir?, He said Yea, I am.....and i said you obviously havent heard me redline 3rd into 4th then........needless to say, he wasnt to thrilled....

So on my way into work this morning as a Chopper bike went past me and made me deaf for the next 5 minutes, i wondered WTF! why doesnt this ******* get pulled over? his is 5x as loud as mine is....so i decided to look into what the law states about exhaust decibel levels and what is "too loud"

EACH STATE IS DIFFERENT, for this discussion, we are going to discuss CA and NY.

Vehicle Code Section 27150 or 27151 of California law requires that all vehicles must be equipped with an adequate muffler to prevent excessive noise from the exhaust system. It also prohibits the operation of a passenger vehicle (other than a motorcycle), or a truck with a Gross Vehicle Weight Rating (GVWR) of less than 6,000 pounds, that has an exhaust noise level greater than 95 decibels, when tested under specified conditions.

From researching, it seems that other states are right around that same decibel level limit give or take a few. The Noise Control Act was implemented in 1972 and had much harsher restrictions it seems. ( 72-78 dBs) Heres a chart to show what kind of decibel outputs come from things we hear every day....

Approximate Sound Levels in Decibels
• Police siren: 118 dB---------------------------• Rock band, disco: 115 dB
• Missing muffler: 115 dB------------------------• Hole(s) in muffler: 111 dB
• Tailpipe damage: 109 dB-----------------------• Circular saw: 107 dB
• Hole/break in pipe/muffler: 105 dB--------------• Internal muffler deterioration: 104 dB
• Heavy truck @ 40 mph: 99 dB------------------• Power mower: 92 decibels
• Freight train at 50 feet: 88 dB-----------------• Printing press: 80 dB
• Vacuum cleaner: 74 dB------------------------• Busy street traffic: 70 dB
• Air conditioning unit: 60 dB--------------------• Interior of a quiet car: 50 dB
• Private office: 41 dB--------------------------• Library: 33 dB

An interesting Statistic -
The most common complaint in New York City’s Quality of Life Hotline number
by far is noise. There were 7,000 citations for noise violations in one year, which led to
1,000 arrests for outstanding warrants. These statistics show that noise is a gateway

I checked the Apex'i website, the only exhaust they gave decibel ratings for was the WSII and they said they are generally in the 80 dB range. They have on each exhaust description though that if you add the Silencer they offer, you can reduce noise up to 7 dB...which is a pretty good amount. alot of the websites have a disclaimer like this one....

Exhaust Systems that are designated for street use retain all factory emissions equipment and conform to the California Vehicle Code 95-decibel exhaust noise level limit. (Note: Some exhaust systems are designated for Off-Road Use Only and are solely to be used for Off-Road purposes)

See that little "Note" on the bottom...yea...that most likely means that about half of the exhausts they offer DONT comply with the law....

It seems that if you get pulled over for an exhaust ticket, the officer SHOULD have a dB reader. The correct way to measure the dB output for your exhaust would be to have the reader 20-24" away from the exhaust at a 45 degree angle on a stationary level surface with an unobstructed area not less than 3 meters wide around the entire vehicle. Then the average of 3 revs to the engine by which the vehicle is propelled run at a constant rotational speed of 3500 revolutions per minute or 3/4 of the rotational speed at which maximum power is produced.

Just thought this would be some nice information to share....also good to know i should be 100% legal with the new WSII i just ordered...

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Old 05-11-2009, 07:36 AM   #2
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Default Re: Exhaust Decibel Levels, and the law....

Never had a problem at all with cops and my WS2. But then again, it's only *barely* louder than stock. And I drive the speed limit and always use turn signals.

<----hates almost all loud exhaust, except my friend's camm'ed fox mustang.
Originally Posted by Arcitekt View Post
here comes vindicator with his 30 line posts.
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Old 05-11-2009, 08:24 AM   #3
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Default Re: Exhaust Decibel Levels, and the law....

The motorcycle thing has always bugged me. Why do they get to be so loud and honda's are getting harassed all the time?
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Old 05-11-2009, 08:35 AM   #4
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Default Re: Exhaust Decibel Levels, and the law....

I was JUST talking to a CA CHP here in napa about the SAME thing.. The fact of the matter is that they're NOT excluded.. It may seem like it, but there is a pecking order in who gets picked on first..

the guys that get it worst is by far the street bike guys, then imports, then domestics and harleys then diesel pickups.. It may not be that EXACT order but you get the idea.. If you have a mustang and a honda next to each other in traffic with exhausts that make the same noise, they will pick the honda over the mustang.. I'm sure it has something to do with the "Profile" of each kind of driver.. For instance, earlier it was called a gateway crime. If a cop sees the opportunity, he'll more likely pull over a honda because they're known to have all kinds of illegal things done, possible stolen or illegal engine swaps, and numerous other citations.. The mustang may have some illegal stuff too, but fact of the matter is most cops HATE imports to boot so it's a double negative pointed at the import tuner kid..
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Old 05-11-2009, 08:51 AM   #5
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Default Re: Exhaust Decibel Levels, and the law....

awesome read! Fortunately, I live in a pretty laid back place, but I do frequent Honda-Harrassing areas, and with no cat it can be tough. My Vibrant flat black muffler helps me fly under the radar both visually and audibly.
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