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How restrictive is the 335i Muffler?
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03-22-2007, 02:46 PM | #1 |
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How restrictive is the 335i Muffler?
When I had my car up on a rack the other day having an allignment I was taking a close look at the Boysen silencer on our cars and it actually looks to be pretty high quality with nice welds, and a pretty cool design with the 2 seperate sections and a cross pipe linking the 2 muffler bodies. It looks much better than the OEM e46 M3 muffler actually.
I am sure this Boysen muffler is heavy as hell but I wonder how well it flows compared to an AM setup. It is pretty tempting to just remove the secondary cats, resonator and the crimped, acute angle bends in the oem mid-section and leave this muffler since I am guessing that will have awesome sound like a more aggressive and a little louder version of OEM. |
03-22-2007, 02:55 PM | #3 |
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That actually sounds like an idea. Do it! I may try it my self unless someone here with real knowledge in exhaust systems
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03-22-2007, 03:24 PM | #4 |
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Stock exhaust is pretty restrictive.... there are so many curshed bends in the system, regardless of how good the welds are on it, and not to mention the mid muffler and other set of cats on it.. It sounds nice but still restrictive... anytime you have a better flowing exhaust sytem on a turbo car, you will make more power and a lot more tq as well.
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03-22-2007, 04:43 PM | #5 | |
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By the way, I am still interested in the muffler shop you were talking about in torrence. Maybe I could get them to do the job for me. If it doesn't turn out as hoped I could just remove the oem and add a couple of Magnaflows. Did you ever get the address by any chance? Thanks |
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03-22-2007, 04:45 PM | #6 | |
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Sorry Terry, I didn't take any pics. I only had my Razr but didn't even think of taking pics. Once I have time I am going to muffler shop and I'll take some pics then. I am hoping CEA can send me the address of his guys because he said they do good work at good rates. |
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03-22-2007, 06:25 PM | #8 |
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Has anyone that has replaced their stock exhaust weighed the thing? I'm guessing there's a fair amount of weight savings to be had, in addition to any performance gains, but would love to have some numbers.
While I'm at it, does anyone know if removing the secondary cats is legal in California? Thanks, Richard |
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03-22-2007, 06:41 PM | #9 | |
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03-22-2007, 07:13 PM | #10 |
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you are legally allowed to change the catback portion, if your db level doesn't exceed a certain number.
can't touch the cat, or the downpipe. i think by removing the cats on the oem exhaust system alone would give you significant gains...less back pressure is always a plus for turbocharged cars. other than your car stinking like crap, some people wrap cat shields around test pipes and stuff the inside with muffler repacks to pass baton tests from cops. this will make the test pipe pass visual test too since it looks like a cat from the outside. once you're sent to the ref station though u'd have to swap the oem cat back on, not sure how easy that is to do with the 335i's oem exhaust design. for my Evo it's 4 bolts. |
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03-22-2007, 07:26 PM | #11 | |
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This law can be a difficult one to enforce... ultimately, it's your risk. |
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03-22-2007, 08:25 PM | #12 | |
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03-23-2007, 03:23 PM | #13 | |
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However, Railgun is right - the state of California doesn't do emissions tests on new cars - only after a car is four years old. I also suspect, unless it looks homemade, that your typical smog station attendant wouldn't be able to pick out an aftermarket exhaust unless it was really loud (which I don't want - just enough so that I can actually hear the thing). But, back to my original question - anybody know what the cat-back portion of the exhaust weighs? Richard |
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03-23-2007, 03:38 PM | #14 | |
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http://www.e90post.com/forums/showthread.php?t=44798 According to UR, the factory is 78lbs and theirs is 55lbs. Also, the 330i muffler is about 30 lbs if that helps any. Good luck! |
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03-25-2007, 01:41 AM | #15 |
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03-25-2007, 01:48 AM | #16 |
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03-25-2007, 01:54 AM | #17 |
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I think both of us should be able to help this forum.
Once the car has broken in somewhat (only 260 miles on it, and Ive had it for 24 hours...lots of driving!), I will be fabbing up a prototype system for the sedan, perhaps the coupe if someone is willing to donate their car for a day or two. It won't look as good and shiny as the major brand ones out there, but considering my old boss and I have some pretty damned good welding skills (well he TIGs too, so he has me beat), I figure some good 321 stainless to borla mufflers should do the trick. HP gains will be there, maybe not as much as the big guys out there, but for the price and the quality of pipe and mufflers, if I can achieve a good tone (if I could replicate the M3 GTR sound I would be in heaven) and make some good power gains while keeping the price below the 4 digit range, I think we'd have a seller no? |
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03-25-2007, 02:26 AM | #19 |
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