12-10-2012, 02:06 PM | #23 | |
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Yes. At least according to RealOEM.com While the parts diagrams look the same the part numbers ARE different. 1M mid pipes... 135i N54 mid pipes... 1M mid pipes (w/secondary cats) bmw #18307845669 135i N54 mid pipe (w/secondary cats) bmw #18307559994 And lets not forget that the 1M also has different main cats than a 135i N54. The 1M's main cats are higher flowing cats than what the 135i came with from the factory. Dackel |
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12-10-2012, 02:15 PM | #24 | |
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THAT is what my friend said. That the pipe that runs inside of the resonator where the mid pipes form a Y... that THAT pipe is a straight thru pipe. So the resonator is a dummy. I really don't know why BMW built the exhaust with that resonator box around the straight (& non perforated) Y pipe.
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12-10-2012, 02:57 PM | #26 |
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I believe it was Harold at HP Autowerks who first mentioned the higher flowing cats of the 1M(I believe). I would start by asking him.
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12-10-2012, 03:06 PM | #27 | |
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12-10-2012, 07:34 PM | #30 |
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What would it cost to have a muffler shop cut out the stock 1M mid-pipe's cats and replace w/ short sections of tubing?
And - does the fake resonator box have any effect? If not on flow, then sound? hmmm |
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12-10-2012, 09:19 PM | #31 |
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I think that was BMW's rather "economical" way of designing a sporty exhaust for 1M in a hurry, while trying to match the environmental norms too! Result is a confused mess, managing not being green or sporty enough. Among the trio most useless section of the stock exhaust is by far the mid pipe, well maybe after the China special muffler
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"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake. |
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12-11-2012, 07:03 AM | #33 |
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Yup! Totally correct.
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12-11-2012, 08:27 AM | #35 |
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Agreed; I'm far from a mechanical engineer but I think it would be for closer regulation of back pressure. Not enough and you loose your low-end Tq; too much and you have spooling issues... Though the logical side of me says, two 3' inch pipes = 6" for two small turbos. My personal opinion, formulated from years of tuning, it's over kill. 4" total would be ample to move the exhaust... It's only a 3.0L motor... You might not get the exhaust note that one would dream of but I'm a functionality person... Plus one pipe seems a bit more manageable then two. Just my .02
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12-11-2012, 10:44 AM | #36 | |
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In terms of cross sectional area, 2 3" pipes is nearly equivalent to 1 4.25" pipe. But a 4.25" pipe should theoretically be able to flow a bit better since it has a smaller wetted perimeter (surface area in contact with flowing fluid) thus less friction.
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12-11-2012, 10:59 AM | #37 |
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i thought that the two pipes on the midpipe are 2.35 - 60mm diameter each
its about 3.35 cross section area
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12-11-2012, 02:04 PM | #38 |
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^ I have no idea... It just seems a bit easier to modify that way vise trying to understand what BMW Eng did. Custom make the exhaust so if you don't like the exhaust note you can add to or take from rather easy.
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01-08-2013, 10:18 AM | #40 |
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People have different perceptions of drone plus as you say Chinese market received modified exhaust muffler for 1M from factory. There were also different diagnosis in relation to source of drone in 1M: muffler, mids or an area under the trunk carpet, or a combination of some/all of these. My suggestion is since you don't have drone or you have but doesn't even bother you, just accept it as it is and don't worry about that, there were other people who claimed they never had any drone outside China.
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"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake. |
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01-08-2013, 10:49 AM | #41 | |
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the reason i am pointing of the is that some chinese 1m owner is not happy with the muffler. It's has a piece of metal that block 2 exhaust exit makes sounded more quite, unbalance burn on exit, and perhaps less power. I am one of those unhappy costumer. So i swap to meistershaft resonator mid and back. guess what?? very annoying drone from 2000rpm to 2900rpm. i cant hear radio, not Bluetooth telephone. even more not happy?? btw, i really like your N55+evolve post, what is one of the reason i have moved to this forum. |
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01-08-2013, 12:28 PM | #42 | |
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I heard Meisterschaft with mids generate drone so maybe you try putting back your stock mids to experiment? One thing is almost for sure the N55 midpipe minimizes and in some cars eliminates the drone.
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"The mark of a great car is one whose overall competence exceeds what you should expect from its individual components and the 1M does just that", Chris Harris.
BMW 1M-SOLD-: TECH: Evolve Race+N55mids, Evolve IC, Michelin PSS, ER cp, aFe filter, CDVx, Vorshlag camber plates, BMS OCC EXTERIOR: trunk spoiler, blacklines, black grills, IND goodies INTERIOR: Alcantara steering wheel, steel pedals, custom mats, MPower e-brake. |
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01-08-2013, 01:01 PM | #43 |
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^ Well I think I'm going to just modify my N54 Mids and see how they sound... The cost of that would be far less then buying new mids and/or buying N55 mids.
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01-08-2013, 01:36 PM | #44 | |
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Got to check the exact price, but from recollection, for the price of one set of N54 mids you can buy 4 or 5 sets of N55 mids. The reason: secondary cats ain't cheap. Don't castrate those dangly bits. Save yourself the hassle, install N55 mids (moreover it's an OEM BMW part) and keep the stock N54 mids for future re-installation purposes (you might be required to re-install N54 mids on resale day - buying those will hurt your wallet). N55 mids are also cheaper than Maddad mids.
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