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03-06-2016, 11:38 PM | #1 |
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Economical exhaust sound improvement?
I have a stock 2007 3.0i that I got recently. I would like to enhance the exhaust sound a bit with out making it raspy or obnoxious to others or too loud while cruising. I just would like to lower the octave and increase the level a bit. The stock muffler just doesn't seem very exciting for this beautiful car!
Performance increases aren't that important, I'm only wanting to replace the muffler which isn't going to change too much except for the sound, I'm not interested in replacing the whole exhaust system and it will have to pass the California emissions checks. Any ideas on what I might be able to get at a local muffler shop? I looked under the rear and it looks like the muffler is attached to the pipe to the cat so would have to be cut in order to replace it? What is normally done? Thanks |
03-08-2016, 10:30 AM | #3 |
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If your car is anything like the 2003-2005 M54 Z4 and 2006+ Z4M, the primary cats are in the headers. Any secondary cats are unmonitored. It's illegal to have the secondary cats removed, and many shops may refuse to mess with them due to potential fines. But, no one will really know if they've been removed, you will more than likely still pass a visual and sniffer as long as the primary cats are in place, and the car won't throw any codes if all the sensors are monitoring the primary cats in the headers (you will need to visually confirm).
Anything aft of the cats is fair game, as long as you don't break any noise laws. The exhaust on the early Z4's is one piece from the headers back. Most mufflers are cut and clamp. You will need to put the car on the rack to confirm. If you have both sets of cats in place, you can put just about any kind of muffler on the car without it sounding terrible. Once you start removing cats or resonators, the car will need a tuned muffler from a name brand company. I personally wouldn't put a universal muffler on my car.
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03-08-2016, 10:57 AM | #4 |
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If your car has secondary cats, I would relocate the secondary O2 sensors aft of the secondary cats (possibly with defoulers) and go with catless headers. That way you get the sound increase and power to go along with it, while retaining an OEM-looking exhaust. If you want more sound, then get an aftermarket muffler.
There is risk involved, since the secondary cats may not clean up the exhaust fumes enough to pass the sniffer or avoid a CEL. It depends on what you're after and how much risk you're willing to take on. Deleting the primary cats will likely result in a 10-15 whp gain.
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09-17-2016, 12:16 PM | #6 |
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Garage List F15 X5 xDrive35i [8.75]
E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.24] |
I would just delete the secondaries and swap mufflers for something like a Borla or Magnaflow and finish off with whichever tips you like. Should run you maybe $350-500.
You will pass emissions without secondaries. Keep them around in case you want to reinstall. |
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