Too Loud

[cobracobra]

The limit is 85DBa!!!! Thats more like it.....

[Michael C Henry]

I bought a finished car in Reno in 99. The headers were all wrapped in fiberglass tape . They were great looking and underhood temps were not that much. I drove the car home on a tripp permitt from Nevada. A few days later while on a quick ride #7 header blew out at the first bend out of the header. Fiberglass shreds wer everywhere. When I unwraped that and other pipes, ther were so many cracks that it was pointless to try to save them. So I set about having another whole set of headers and sidepipes made. I found out that the fiberglass tape keeping all the heat in the pipe helped cause that condition. So I looked around and setteled on ceramic coating as an alternative. As I looked through the Revised Code of Washington for noise standards . All I found was that I could not amplify the exhaust noise level. So being so old and experienced and knowing that a Cop can hold you up. and if so I'd have to do something to show I'd change something in order to comply. I figured I'd make the exhaust system mechanicaly accessable. So I setteled upon Burn's Stainless Steel exhaust parts. I went with 3 1/2" "V" clamps and flanges and had them tigged to the collectors and mufflers and turnout pipes. I used the Car Chemistry disk units in the collectors with nuts welded to the disk units and washers on the collectors to form a flat outside bolting surface. End result was I ended up with three different muffler sets Original,Lobak, and 3 1/3" open pipe. I can add or remove the disk units. I can turn the turn out pipes anyway I want. I can even mount the turnout pipes directly to the collectors if I wish. All ceramic coated and covered with the perferated SS heatsheilds. No grinding or further welding required.

[Michael4yah]

If its only a temporary thing just to get it passed then you might try a loose roll of chicken wire. You only have to lose 3db to be legal, Roll it up, put it in and let it unravel inside the pipe so that it doesnt blow out, and to get it out you just have to grab the centermost end with some long needlenose pliars and wind it back tight till you can pull it out and Violla!! I havent done it in years so you better take a torch to it and make sure this cheap stuff from China doesnt melt in your pipe. If not it should work for 5db.

[ceslaw]

Here is a question. If one Dynatech Vortex Insert quiets it down just a bit, what would happen if two were inserted, back to back in each side pipe? If the increase in back pressure is minimal, as claimed, the loss in performance should be minimal. But reducing the sound by 4 db instead of 2 db would be noticeable. Any one have any experience or thoughts?

Chusk

[stush]

The Dynatech vortex would not fit in the exit turn out of my pipes so I cannot directly answer your question. I have spoken to people who have used them at the exit end of the pipes and they tell me it eas not so much a noise reductiona s a differnet tonal quality to the sound. Probably more effective in sound reduction at the collector end of the pipe. I will say that the discs from car chemistry did a good job in reducing sound and were easily installed and removed from the collector end of the pipe.

Stu

[Don]

Chusk

I did not word my inquiry to Dynatech correctly, but the reply I received mentions your thoughts in the 2nd sentence

From: "John Gaston"
Date: July 24, 2006 10:03:11 AM EDT

Subject: RE: Vortex Cones

Hi Don

You would not want to place two Vortex insert cones end to end. They are designed to work with the end or tip of the cone facing the motor. We have not done any testing on placing two Vortex cones in line with each other or one right after another, sorry.

Thank you for your interest in Dynatech Exhaust.

John Gaston
Sales/Technical Support
Dynatech Headers
www.dynatechheaders.com
jgaston@dynatechheaders.com
800-848-5850 Ext. 271 Phone
812-751-5513 Direct Phone
800-319-2551 Fax

[ceslaw]

Thanks for the quick reply.

My plan is to install the inserts into the ends of the side pipes. 3 1/2 inch would fit. There is a good eight inches of length to work with, which I assume would be enough.

Can I expect an appreciable difference in the volume and sound quality?

Car is an Everett Morrison. They doubled the usual number of baffles, yet it remains really loud.

Thanks for your interest and quick response.

Chuck

[Don]

Chuck:

This has been a learning curve for me as I attempt to reduce the dB level with my side pipes, so I am still in the early " Learning " stages. All references I have seen on the use of Vortex cones has been to insert in the header collector for maximum benefit. Also, ( I think ) the HP, cam , etc of the engine does/could impact the reduction in dB. Car Chemistry discs have also been referenced for the same placement, i.e. in the header collector.

http://www.secureperformanceorder.co...re/vortex.html

You might want to consider contacting John at Dynatech for his opinion:

John Gaston
Sales/Technical Support
Dynatech Headers
www.dynatechheaders.com
jgaston@dynatechheaders.com
800-848-5850 Ext. 271 Phone
812-751-5513 Direct Phone

I would be interested in his response

Don

[badrich]

In my attempt to bring my Cobra's exhaust note to a *reasonable* level, I replaced my old, stock, blown out glasspacs with 18" Race Lobaks, with some success. Still too loud and raspy, so I installed a pair of Vortex cones in my collectors. Just a tad quieter and less raspy, but still nasty. Not bad. Cruising on the freeway doesn't necessitate ear plugs, but I'll probably still use them on trips. My ears aren't what they used to be, and I want to preserve what hearing I have. While my current setup is pretty good, if I had it to do over again, I would have gone with the 24" Lobaks and Vortex cones. My neighbor next door still hates me. Hey, I tried. Rich

[Don]

For the AMX I use the DynoMax CVX mufflers with a X pipe. The dB for these mufflers is 82 compared to 86 for the Borla and 92 for the Flowmaster. Measurment at "Half meter static test @ 3200 RPM " The sound level is reasonable , not offensive , both at a steady highway speed and when accelerating, taking into consideration the rear exit for the exhaust.

I contacted Dynomax Tech Services and mentioned the need for a street Cobra side pipe muffler and as a starting point used a length of 28 to 30 ", 4 " round case, tapered at the ends to 3" For the dB level I used the CT standard which is:

CT DMV Section 14-80a-4a , Allowable Noise Levels since Jan 1, 1979. The maximum dB for a stationary test is 72 dB for soft site( grass ) and 74 dB for hard site ( pavement ). Section 14-80a-9a mentions the distance for measuring the dB. The baseline is 48 feet or more but less than 58ft. An adjustment to the dB reading is made up or down for readings either closer or farther away than the baseline range. The max reading is 81 dB for a hard site, highway operation above 35MPH, using the 48 to 58 ft baseline for measuring.

Received the following reply from DynoMax:

From: ta-walkertechline@Tenneco.com
Subject: Dynomax Exhaust
Date: August 23, 2006 1:45:54 PM EDT

Thank you for your inquiry for Dynomax Exhaust. We appreciate your
interest in our products. In regards to the muffler design you are
requesting, we have no immediate plans on releasing such a product, however my engineering department has been given the requirements for future consideration.

If you have any further questions, please feel free to contact our tech
line at the number below.

Thank You,

Lisa Kortz
Dynomax Performance Exhaust
Installation Technician

Tech Line Number
1-734-384-7806

Should anyone else desire to contact DynoMax, the more inquires they receive , might someday make the muffler

http://www.dynomax.com/tech/email.asp