E46 BMW M3 Turbo: Part 2 – Splitter, diffuser, 3.5-in exhaust, and dyno testing!


This shot shows us the part that hooks up to the a stock section 2, which comes off the headers (the headers is considered “section 1”).  This means the Magnaflow/BimmerWorld exhaust is a stock replacement cat-back system.  The only drawback, being a single-tip exhaust, is that some may not prefer the look with the factory rear section, which has provisions for a quad-tip exhaust.  It can be done, most certainly, but you’ll have the provision for the dual-tip outlet on the right/passenger side empty.  If you’re planning to run this exhaust, we highly recommend this diffuser.


We cannot confirm perfect fitment of the 3.5-in exhaust to a factory section 2 because this car doesn’t have the factory section 1 (it’s a turbo car with a turbo downpipe, remember?).  So, while four out of the six flange holes lined up perfectly, a little bit of drilling-out of the holes to make them bigger did the trick, as seen being performed by MKC’s Ryan Charlton here.

It should be noted that this piece going into the Section #2 portion of the exhaust is now manufactured by Magnaflow themselves, which BimmerWorld reports has a much better fitment.  They weren't totally satisfied with the early units. And if BW says that these new exhausts feature a great fitment, we believe them.  That sucker is a perfect fit!  Read about it in the next couple of pages.

One of the upper holes needed to be opened up as well, and the drill bit can’t be aligned with the whole while the exhaust is installed.  Here is Ryan performing this task on a workbench.


Once the front was loosely bolted on, this allowed us to align the rear, which Ryan is doing here.  It lines up great!


Here is the muffler finally secured with the supplied silicone exhaust hangers.  When compared to the installation of a factory quad-tip exhaust, this Magnaflow unit is a lot easier to bolt up!


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