Too Loud

stush · #1 (**permalink**) 05-22-2006, 12:12 PM

Don,

Thanks for your measurements. Going back tomorrow to Weatherfield. Have a CC 3 disc insert with packing. No center restrictor. Sounds more muffled but my home measurements were still a little high I think...very windy day throws it off. They measured behind the car though I think the state statue is supposed to be perpendicular but not less than 70 degrees. Is that right? Since they measured from 50 ft behind the car were they in the wrong? I made a restrictor like the fellow showed in the picture but used perforated Al and expanded metal. Seems to have lowered it further. Will be testing again later if the wind dies down. Check with your knowledge about how the test should be done with regards to angle of measure and let me know.

Stu

Don · #2 (**permalink**) 05-22-2006, 03:21 PM

Stu:

Go to:

http://www.ct.gov/dmv/cwp/view.asp?A=801&Q=252796

Scroll Down to " Are Glass Packs Legal " and click on
Sec 14-80a-1 through 14-80a10a

Should get the PDF file,"Maximum Permissible Noise Standards", on pages 164 to 166 is Section 14-80a-7a Measurements of Noise Emissions, which is the standard the DMV Inspectors should be using for testing , the test site diagram is on page 166. May or may not be a good idea, but depending how the inspection is going, ask the Inspector if they are follwing the standard mentioned above which is Sec 14-80a-1a to 14-80a-10a

The test site diagram, for the 35 mph test, must, I think but not sure, be a side reading as the test should be conducted as the vehicle approaches and drives by. Otherwise, from the rear or front the vehicle would be accelerating, not a constant 35 MPH

For the 35 MPH simulated test where they ask to accelerate the motor, might want to consider not exceeeding a RPM than the equivalent of 35 MPH in high gear. When I was racing the motor to a quick full throttle, really got some extrteme high readings as the RPM far exceeded the equivalent of 35 MPH.

Note: I have had problems copying the DMV link above, might not work. I do not have the software to copy the PDF file.

Car Chemistry and Vortex Cone both mentioned their hardware is most effective as close as possible to the primaries.

GOOD LUCK !!!!!!!

stush · #3 (**permalink**) 05-23-2006, 08:42 AM

Passed inspection this time. The sound was so muffled they didn't even bring out the dB meter. Thanks everyone for all your help. This website is worth its weight in gold.

Stu

Buzzmobile · #4 (**permalink**) 05-23-2006, 09:08 AM

Now, Pull all that crap outta there and go have some fun!

Don · #5 (**permalink**) 05-23-2006, 11:43 AM

Stu

CONGRATULATIONS

Way to go, the best way for a natural high when the DMV Inspector stamps the forms " Passed "

Any other words of wisdom for those that will have their Composite/Kit inspected, and specifically the CT inspection on noise, etc., etc.,

Regards

Don

stush · #6 (**permalink**) 05-23-2006, 02:18 PM

Best words of wisdom is stay calm and friendly. Make sure all your paperwork is in order. The car was so quiet this time they didn't even pull out the dB meter. Used car chemistry 3 disc inserts at the collector end and made a restrictor for the turn out of alternating discs of perforated aluminum and expanded metal which I cut and bolted together. The only trick was keeping it in place but the pictures posted on this thread were a great help and basically duplicated that. Still not sure what standard they use but after reading the state guidelines it is probably considered a stationary test. Thanks everyone for all the help and advice...now it is time to enjoy the car.

Stu

Don · #7 (**permalink**) 05-24-2006, 07:48 PM

In Grassroots Motorsports there was an advertisement for Vibrant Performance. I contacted the company referencing the CT dB standards and asking about a muffler specifically intended for Cobras. Included was the following comment . First time that I had seen a reference to an SAE standard on dB for exhaust noise.

"So you know, the Connecticut sound test you have referenced has been largely discredited by SAE (Society of Automotive Engineers) as being ineffective. In 1998 they released a new standard (known as J1169-1998) for exhaust noise testing that is the standard used by California and some other states. The new standard allows for a stationary db level of 95, at a distance of 1.5 meters from the tailpipe. This standard has proven to be very fair to manufacturers and enthusiasts alike. "

Anyone from CA familiar with the standard mentioned above ?

http://www.vibrantperformance.com/vi...rformance.html

cobracobra · #8 (**permalink**) 05-25-2006, 02:44 AM

Sorry I havnt logged on in a while....I finally passed yesterday and going today for my plates....1st inspector failed me on, get this 12 items! Needless to say 10 were BS! I can say that the supervisor there is a great guy and understands these vehicles(no names being mentioned) MAKE SURE WHEN MESURING YOUR SOUND YOU HAVE IT IN THE RIGHT SCALE..DB-A not C! @ idle I was at 66DBA but 81 at C. @ 2000rpm im at about 70DBA. thats with the supertrapps on and measuring on the safe side of 40 ft behind the vehicle, im about 1 DBA less @ 50 ft.....

-Mike

stush · #9 (**permalink**) 05-25-2006, 03:47 AM

Although the SAE may have discredited the standard, in the Peoples Republic of CT it is what they go by.

So the first time they only had you go up to 2000rpm? If I had done that the first time I may have passed. I do not know who the supervisor was but the guy doing reinspection was kind of a tough nut, then we he decided I passed he was friendly. When I came back after having paid the $50 VIN assignment fee, he took great care in selecting a place to put the tag. Complemented the car, wished me luck in my enjoyment, wished for plenty of sunny days to drive, and even asked if there is a way to get a soft top.

Stu