Still looking at options to get a little bit more exhaust noise. Following the various exhaust threads I haven't seen anyone who has left the OE muffler in place and deleted the (center section) resonators. Has anyone done this and if so what did it sound like?
Resonator Only Delete on Si
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The rear muffler replacement is inexpensive and reversible. There are a number of after market options available and at least as many opinions as to their advantages. But with any of them, if you screwed up and still have the original silencer you can undo what you've done. To remove the primary silencer you'll have to cut it out and weld in a straight piece of pipe. Yeah, could could weld the primary silencer back but either way you have brittle weld joints waiting to fail and you still have a set of tail pipes that look cheap. Shop the aftermarket. I think you'll be happier in the long run.
The part you refer to often gets removed and replaced as part of any cat back conversion. It's actually a 2 part function, resonator and balancer. Removal won't make much increase in noise but will give a different sound depending on the exhaust set up.
I removed mine such that cylinders 1,2 and 3 use one back box and 4,5 & 6 the other. A pleasing sound is created, but key to this was going quad.
However if you just pipe it back into the same rear box all you've done as TO/M says is removed an expensive and difficult to replace bit.
I removed mine such that cylinders 1,2 and 3 use one back box and 4,5 & 6 the other. A pleasing sound is created, but key to this was going quad.
However if you just pipe it back into the same rear box all you've done as TO/M says is removed an expensive and difficult to replace bit.
50% of the noise, and quality of noise (ie, pops and bangs on the overrun, de-muffling/bassing the real noise), is killed in the back box anyway. I bet it's a damn site louder/more agressive with just straight pipes rather than a stock back box in place 
The resonator will likely be there to improve exhaust flow (pulse tuning?!)
Dave
The resonator will likely be there to improve exhaust flow (pulse tuning?!)
Dave
CJ: I see in the parts listing that these are identified as a catalytic converter/front silencer. When you did your system, by any chance did you take a close look at these? Are they secondary catalysts?cj10jeeper said:
The Zed has 2 sets of cats. Precats right up near the manifold and the main cats about a 1/3 way back. Behind both of those and before the backbox, is a kidney shaped resonator, so in effect there are 3 items in the system before the backbox.
I did not remove either set of cats but removing or replacing the cats is a common thing to do. I'm told by the guys that did my system that I could remove the rear cats and it would still pass emission tests and be noisier, but I opted not too.
I did not remove either set of cats but removing or replacing the cats is a common thing to do. I'm told by the guys that did my system that I could remove the rear cats and it would still pass emission tests and be noisier, but I opted not too.
crooner12 said:
I believe it is primarily a balancer, but also helps tune the sound to one that BMW decided is correct for the car. I'm open to better suggestions though