decible levels
#3
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Join Date: Jul 2001
Location: Lincolnshire IL
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Re: decible levels
I just had my twin HP 500s (carb) tested at 91.3 dbl ... this was WITH HPI mufflers. I had hoped for a lower #, but I passed (had to be under 91.5).
#5
Charter Member #601
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Re: decible levels
Make sure the cops are do the test properly.. I know here in Mich they dont follow their own rules. One meter back and 1.5 meters high, if I remember correctly. Standing on my swim platform that is about chest height for me. They usually put it 1 foot from the end of the pipe. I just stay away and have big mufflers and shotguns.. they drag in the water and that helps.. Go to radio shack and get the meter, and check it yourself. Carry a tapemeasure and a copy of the law if you pass with your meter, theirs should agree. There also should be no abient noise in the area (jet ski's, etc) and no reflective surfaces.. like the side of their boat.. Some around here go to court and they win..
Dick
Dick
#7
Registered
Re: decible levels
Through hull exhaust above the water line, no mufflers and you will fail. The difference of 88 to 91 (3 dbs) is twice as loud. The guys with mufflers are running 91 and you need 88. A outboard fishing motor is about 88. Get the exhaust below the water line with mufflers if possible.
#8
Re: decible levels
Originally Posted by Mr Gadgets
There also should be no abient noise in the area (jet ski's, etc) and no reflective surfaces.. like the side of their boat.