Testing for db's

[Kindsvater Flat]

After the other posts I was wondering what kind of db's my boat was producing. So off to the sheriffs office I stole there db meter for the weekend.
I tested just here at my shop and not on the water. And I figured that since the db meter issued by the Coast Guard its got to be accurate.
First test is idle with no baffles.
87db at idle
http://www.dragboatrace.com/mike/87nomuffler.jpg
Second is testing at distance with no baffles.
71db at idle
http://www.dragboatrace.com/mike/71nomuffler.jpg
This is the baffle that I'm using.
http://www.dragboatrace.com/mike/muffler.jpg
Third is testing at idle with baffles.
78db at idle
http://www.dragboatrace.com/mike/78muffler.jpg
Last is at 3,000 rpm at the back of the boat with baffles.
96db
http://www.dragboatrace.com/mike/3k96muffler.jpg
So the big question is... What will it do underway with water flowing through the headers and what would it be at full throttle? Probably a ticket.

[Danhercules]

So................ With the tests you took, you would pass!! Here is what I found on another post. (In Hot Spots West).
Were you 3.3 feet from the transom?
J2005 stationary test. This test is from 4 to 5 feet above the water at 3.3 feet from the transom. Test is at low idle speed in neutral. For engines manufactured before January 1, 1993, a noise level of 90 dB(A). For engines manufactured on or after January 1, 1993, a noise
level of 88 dB(A)
J1970 shoreline test. Test may be taken from any distance from shoreline. This test can be administered from shore, from a platform or from a boat so "shoreline" is a bit misleading. Drive by a patrol boat administering this test even at part throttle and you may have a problem. A noise level of 75 dB(A) or below is required to pass. 75 just isn't that loud.

[Rexone]

Water normally dramatically reduces noise level vs. dry. On average those silencers will knock off 8-11 dB(A) at whatever level (with water). Every boat is a little different though. Different exhausts, different cams, different motor size and heads, all affect noise levels.

[Kindsvater Flat]

I would pass the dock test yes but not the shore test unless I was at some distance. It would be close but won't know until I'm on the water trying it. Also at WOT the water shuts off to the headers because where it picks up is no longer in the water. :D

[Kindsvater Flat]

Rexone:
Water normally dramatically reduces noise level vs. dry. On average those silencers will knock off 8-11 dB(A) at whatever level (with water). Every boat is a little different though. Different exhausts, different cams, different motor size and heads, all affect noise levels. Well with those custom Rex baffles I should pass with flying colors.....right Mike?

[Cole Sanger]

I have some zoomies with baffles. I am selling them new. The reason is that I was afraid that I wouldn't be able to pass a noise test in AZ/river. I was just wondering, if the test is supposed to be so far from the transom and so many feet from the water, how would zoomies do? They point into the air more than the transom. I don't have them water injected, but I have eight mini baffles. Anyone tried a test on zoomies that could let us know? I would like to keep them more than to sell them.
http://www.***boat.com/image_center/data/500/643Zoomies-med.jpg

[Infomaniac]

Cole Sanger:
I have some zoomies with baffles. I am selling them new. The reason is that I was afraid that I wouldn't be able to pass a noise test in AZ/river. I was just wondering, if the test is supposed to be so far from the transom and so many feet from the water, how would zoomies do? They point into the air more than the transom. I don't have them water injected, but I have eight mini baffles. Anyone tried a test on zoomies that could let us know? I would like to keep them more than to sell them.
http://www.***boat.com/image_center/data/500/643Zoomies-med.jpg Alcohol or gas?
Alcohol engines are way quiter than gas.

[Cole Sanger]

I will be putting a gas engine together for it.