tblrklakemo

mufflers.......suck

Ratickle

Here is most of SAE J2005 testing procedures.

Excerpt from SAE J2005
(copied and pasted from pdf)

4. Procedure

4.1 Measurement Site—A suitable site is a body of water free of large obstructions or reflective surfaces such as
buildings, boats other than those involved in this procedure, large embankments or breakwaters, etc. for a
minimum distance of 8 m (25 ft) from the boat being measured. The boat being tested shall either be moored
to a dock or lashed to another boat. If moored to a dock, the dock shall be of open construction so that it
presents a minimum of reflecting surfaces. If the measurement is made in open water, the boat being
evaluated shall be lashed to the measurement boat to prevent relative motion and to allow positioning of the
microphone in the prescribed location. The measurement boat shall be positioned to minimize reflected
sound.

4.2 Boat Operation—The engine shall be operated at low idle speed within the engine manufacturer's
recommended operating range, in neutral gear if so equipped. For motorboats without a neutral gear, the
engine shall be operated at its lowest operational speed. The engine shall be operated for a sufficient amount
of time to allow water to flow through the exhaust system before taking measurements.

4.3 Measurements

4.3.1 The microphone shall be placed at a distance of 1.2 to 1.5 m (4 to 5 ft) above the water and no closer than
1m (3.3 ft) from the vertical projection of any part of the boat in the area adjacent to the exhaust outlet(s).

4.3.2 The meter shall be set for slow response and the A-weighting network.

4.3.3 The observer reading the meter shall not be closer than arm's length from the microphone to minimize sound
reflections.

4.3.4 The applicable reading shall be the average sound level measured during a period when the background
sound level is at least 10 dB lower than the measured sound level. Background sound level includes wind effects, noise from boats other than the one being measured, wave action, boat wakes, and other extraneous
noises.
Peak readings of intermittent sound levels created by wave slaps or changes in sound level due to
wave action and/or engine speed variation shall not be included in the applicable reading.

4.3.5 The observer shall record the applicable reading and the background sound levels taken immediately before
and immediately after the applicable reading.

5. General Requirements

5.1 The measurements shall be conducted only by persons qualified by training to perform these measurements.

5.2 Proper use of all test instrumentation is essential to obtain valid measurements. Operating manuals or other
literature furnished by the instrument manufacturer should be consulted for both recommended operation of
the instrument, and precautions to be observed.

5.3 Proper acoustical calibration shall comprise the complete measurement system including extension cables,
etc. Field calibration shall be performed immediately before and after each test sequence.

5.4 A measurement shall be invalid if changes in the background sound level affect the applicable reading.

5.5 The use of the word "shall" in the procedure is to be understood to be mandatory, while the word "should" is to
be understood as advisory.

PREPARED BY THE SAE MARINE SOUND LEVEL SUBCOMMITTEE OF THE SAE MARINE TECHNICAL COMMITTEE AND THE SAE SPECIALIZED VEHICLE AND EQUIPMENT SOUND LEVEL COMMITTEE

Ratickle

Here is the main points of the pass-by test as it is stated in the patent application for the new noise gun they are trying to get approved in Michigan. If they get it approved then the legislature will try to get the noise law modified to mimic Wisconsins and add the use of the gun. There is currently nothing we can do in MI until the technology is approved, (jointly funded by the State and Michigan Lake and Stream Assoc), and actual legislation is submitted.

The SAE J34 standard (SAE 2001) is referred to in the laws of fourteen states. It seeks to provide a comprehensive test to determine the maximum sound level of the boat in use. A summary of this test is as follows: [0016] A test site must be created as shown in FIG. 1. [0017] The boat must pass within of 3 m (10 ft) on the outside of the buoys. [0018] The boat must be at +/-100 rpm of its full throttle rpm range. [0019] The microphone must be placed 1.2 to 1.5 m (4 to 5 ft) above the water, and no less than 0.6 m (2 ft) above the dock surface. [0020] The background level must be at least 10 dB lower than the level of the boat. [0021] The wind speed must be below 19 km/h (13 mph). [0022] The peak reading as the boat completes the course shall be recorded. [0023] Two readings will be made for each side of the boat.

epeek

I wouldn't say that. We certainly appreciate your willingness
to bring up test mufflers. I would love to try them on mine.
I also personally like the way they sound and work. I
wasn't posting as a knock to CMI. Just relating what
I have encounterd so far. Perhaps the mechanism can
be tightened up to make them pass sound testing.(I dont know) In CMI's advertisment they say they can reduce noise to
85 decibels. I would say a 500 or 525 is pretty standard
power so why are they testing out at 91-92 ? Do they
have to be set up before installation? Could you get
ahold of CMI and let us know? As far as the sound test,
I've been tested twice by the patrol. I know exactly how
they perform it. Ken Colletes 38 ZR got tested with his brand
new CMI's by the patrol and failed. (525,s) He tested out
exactly at what I had him at. 91-92 db's. My boat tests
out exactly the same with my meter and the patrols. We
did it together and he showed me exactly how the test
is performed and check my meters calibration. It was
perfect.

Too Old

Info passed on to the folks at CMI. Yes, the mufflers can be tuned slightly, but I'd like to think they'd be legal right out of the box for smaller HP applications.

We'll see.

Thank you for the information.

Fred
the "Too Old" guy

epeek

Thanks fred, appreciate all that you do!!!!