i have bought a cannon style muffler from trademe for my diamante, it will be a fair bit louder than stock, and ive come up with a plan to make it variable between loud and quieter. The diamante has a system where a vaccuum operated bellow device in the boot opens and closes a valve in the muffler, via cable like a throttle, that restricts its flow when cold to aid engine warm up and opens when warm. I had disabled the system as it was rusted closed. I simply set it open. Im planning to mount an exhaust silencer insert in the tip of the cnnon and have it close or open on demand. I can tee into the vacuum line or use the little electric valve via a switch to operate the bellow. I could even hook it up stock and have the exhaust quiet when cold and open up when warm. Any thoughts, ideas? The main setup is all there just have to mount the throttle setup to the top of the exhaust tip, where it wont be seen.

Very similar to the Varex setup..

Have a look at what they do.. There would probably be a few ideas for you to copy there..

SuFz

yeah thats what i thought , keen on hooking it yp as stock so its quiet during the warmup period and opens up once shes warm. Im also tempted to cut open the stock muffler and try modify that as it has a pipe that exits the muffler on the side and then reconnects near the front. The butterfly is in this section.

im going to get another section of exhaust from pickapart to weld cannon to so i can exchange between the stock exhaust and cannon. I also want to cut open stock exhaust to modify it possbly to use the stock variable system . Depends on its internal layout

ok i have removed the rear muffler and will be cutting it open today to see how it works will take pics. My canon should arrive today, running it strait through for now actually sounds awesome, nice and deep, and not to loud (well legal) lol the 2.5 inch stock exhaust seems to make the tone deeper compared to my old 3.5l sohc with the 2.25 inch was

heres a pic of the internals of the jdm exhaust, i actually had the system figured wrong! the valve opens and allows easy flow when cold then closes when warm! routing the exhaust gas through a smaller hole (about finger size) just under the main inlet pipe. im thinking maybe at high revs it opens again as the flow through the small hole is alot less than when its flowing around the external pipe. i think it was stuffed with filler as there is remanants of some. i had set the butterfly closed!!! explains why i have felt an improvement up top in the rev range now ive removed it,
http://i694.photobucket.com/albums/vv302/robssei/95%20Diamante%2030M/17102011.jpg

have fitted my new rear muffler, sounds awesome, a little drone in fourth at 50 to 60kph around town under mid throttle but the increase in resopnse and top end power more than make up for that. i am still hoping to use the butterfly valve off the old muffler, drill holes in the butterfly and see if it dampens the note.

well i have fitted the butterfly valve, one to extend the muffler further out the back, to stop the drone/buzz (which it did) and so i could altyernate betwwen half open and fully open. at half open the exhaust nor is quieter and less intrusive, still burbles nicely at idle, and still flows better than stock. at full open it is louder and deeper, and sounds really nice but can drone a little at low revs. i am going to hook up the stock control system for the butterfly as i tested it and found it opened the butterfly on the stock muffler briefly at startup, then closed , and opened it again at 4000 rpm and and it stayed open till it dropped below this rpm. i will have this hooked up to my setup so the ecu will have it half closed at low revs, and once 4000rpm hits, it will open fully. already got it ready to go just need a cable to complete the setup, will use a bike brake cable. heres pics
vacuum operated bellow and switch
http://i694.photobucket.com/albums/vv302/robssei/95%20Diamante%2030M/25102011006.jpg
butterfly
http://i694.photobucket.com/albums/vv302/robssei/95%20Diamante%2030M/24102011.jpg
http://i694.photobucket.com/albums/vv302/robssei/95%20Diamante%2030M/24102011001.jpg
on car as is
http://i694.photobucket.com/albums/vv302/robssei/95%20Diamante%2030M/25102011.jpg

just to complete thread, cable is hooked up and works perfectly, sounds great, no low rev drone, nice idle note. suprised this thread hasnt had more interest!! im looking for opinions etc.

Im interested, how much for the butterfly assembly at a wreckers over there?

ill see be about 10 to 15 dollars they are on a few diamantes, but the 30m model has the larger diameter .

i would have suggested to get a verix exhaust, but respect for making your own!!

cheers mate! I would have got a varex but kids and bills prohibited it lol. Works a treat and i love the exhaust tone especially at idle