In redoing the side exhaust system using the Arizona Exhaust mufflers, I also placed the Car Chemistry disc inserts directly into the header collectors. This is in addition to the Arizona Exhaust mufflers. Different objective of reducing the db as much as possible without too much, but some, restriction being added. Sound is very mellow at normal driving speeds. The inserts, are available in either two or three disc style in 1/2" increments from 2" to 4 1/2". The factory CR header collector uses a 3" insert.
Summit Racing sells the Car Chemistry disc inserts, page 192 on the latest catalog. Lucien informs me that he has received similar requests for a low db muffler, but without the reverse baffles.
Car Chemistry has a web site, maybe someone with a physics background could further explain the principle of sound control employed by the disc insert technology. The two disc inserts, I used a three disc, without a muffler are advertised as meeting the NHRA noise requirements.
No doubt that the use of the disc inserts did add back in some restriction.but the primary objective of reduced db level with a minimal amount of additional restiction/back pressure was obtained, I think.
Car Chemistry
POB 950
1060 B. Enterprises DR
Midlothian TX 76065
972-775-8124
www.carchemistry.com