I am looking for help or suggestions on exhaust design for my RX-8. Normally I would just buy one, but I believe that the aftermarket companies may be decreasing performance by using a dual setup like the factory did. I do not care much about how this looks, so a single will be fine. The other question is which piping diameter to go with. I am pretty new to rotaries, but have heard that they like the lowest level of restriction possible. Is this true? I don't care much about the bottom end, so whatever helps power from 5K up is what I am interested in. With these things in mind, I am thinking that a 3 inch system with a good straight through muffler will be the way to go. This will be a street driven car, so I will probably use a muffler that will allow the exhaust to make two passes. Of course this will do nothing if the manifold and midpipe are not addressed. So, I am thinking a midpipe and cat of 3 inches in diameter and a header that will have larger head pipes with a 3 inch collector. There is a wealth of knowledge on this board that I think will help guide me in the right direction. Thanks.



BTW Sorry for the length. I was trying to be as thorough as possible.

 

i would do 2.75" ... and just get a pipe contructed from the header all the way back........with a nice muffler at the end





so basically your ideas....but a little less open, 2.5 is good for na... id use 2.75

 

whats the stock diameter? yes rotaries dont like backpressure, although the renisis should be less sensitive about it, but you also want to keep some velocity in there so going too big on the pipe is bad too. somewhere around 2.5"-3" is prolly the happy spot