i opened k20a R muffler and was surprise to see a flapper valve that opens when on wot or near wot. when flapper valve opens, it bypasses all the baffles and goes straight out to the exhaust pipe. here is a link to pix.

http://www.imagestation.com/al...idx=2

 

yes, the valve opens at higher rpms, while staying closed at lower rpms.

 

yea I have the catback on my dc5. sounds nice.

 

Yea I saw this somewhere else too. Cool design.

 

does anyone know if this is true for the RSX Type S muffler?