100 Dba
#23
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#24
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You have to remember that for every 3db of change that is either a doubling of noise or halving it, depending on which way you go. To knock 4db out is a big jump. Still not enough to make it legal.
I am running Borla 4" x 16" mufflers with the old style Drew's, with totally dry exhaust. Works quite well. I intend to buy new ones and that will decrease the noise even more, because the holes are in the bottom of the Drew, which is dragging in the water at idle. Now for those late nite excursions when stealth is very important.. a switchable is necessary.
And when measured with my Radio Shack meter, by Michigan law, 1 meter back and 1.5 meters up (3'x 4.5') I see below 90dba. That is at 700 rpm. When in gear I can get it to idle around 550-600 rpm and the officers leave me alone.
Hope this helps.
Dick
I am running Borla 4" x 16" mufflers with the old style Drew's, with totally dry exhaust. Works quite well. I intend to buy new ones and that will decrease the noise even more, because the holes are in the bottom of the Drew, which is dragging in the water at idle. Now for those late nite excursions when stealth is very important.. a switchable is necessary.
And when measured with my Radio Shack meter, by Michigan law, 1 meter back and 1.5 meters up (3'x 4.5') I see below 90dba. That is at 700 rpm. When in gear I can get it to idle around 550-600 rpm and the officers leave me alone.
Hope this helps.
Dick
#28
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I got around to measuring my boat this past weekend...
110db open, 102db with the Teagues closed.
110db open, 102db with the Teagues closed.
#30
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Did a sound check on my 502's last week....the F302 came from the factory with a swim platform and 330s so the 3" stock pipes were about half under water on the transom. I opened it up to 4" dia when I put the new 502's in....and put the drew shotguns on it at that time. I measured at 88 db at idle 3 ft behind with both motors idling at 650 rpm. Maybe could get a tad lower if you and the passengers went to the rear of the boat when they take the test....but the slots in my shotguns are already underwater anyhow about an inch....