Can anyone suggest a site where I can read up on muffler design?
We have a problem in nz with noise... the police don't like it, even a quiet exhaust and are coming down really hard on rotary owners now.
Because n/a rotaries are generally louder than turbo I need to come up with a high flow muffler that actually does the job, not just looks good
Tri pass mufflers seem to choke the performance and after a few months split the seams but straight through is a little too loud, although good for performance.

Any help would be much appreciated.
Thanks. Rich

 

Mazdatrix has real good high flow mufflers that aren't too loud.

 

I know you asked for places to look up design but racing beats mufflers are very quite for aftermarket and they still flow well.

 

Just run a really quiet stock muffler or really restrictive quiet muffler and then use an electric cutoout somehwere before it. You can have quiet and loud at the flip of a switch. Here's a link:

http://www.quicktimeperformance.com/qtec.htm

I wouldn't necessarily put it in the location shown but rather run the pipe straight into it and have the muffler branch off from it. Just reverse the diagram. This oulw help flow. It would be damn loud but would solve your problem.

 

Hmmm....

I like the idea of that system. Especially if you ran nitrous off the same switch

 

Hey bro, I live in New Zealand and have a 12a bridgeport in my sev. I have two 2 & 1/4 pipes to the diff with two cobys in them, after that a I have a huge RPS muffler from pitstop. Its louder than your average car, but for a rotary its very tame.
You can still hear it porting out something chronic as it shakes the whole car, but you can easily talk in the car and outside it.

 

I use similar systems that most would call quiet but it still isn't good enough for cops at the Mount. I'm trying to come up with a really effective design.