Project E46 M3 seems to live on MKC’s dyno.  I have owned it 1.5 years and it’s already seen 164 pulls.  Five of our seven featured articles include dyno testing, too.  BMW built a great motor that, now with our AEM Infinity EMS, runs perfect.

Project E46 M3: Part 7 – Magnaflow vs Corsa Cat-back Exhaust Systems

Which one would you take?

by Pablo Mazlumian


In Part 2, we installed a Corsa RSC cat-back exhaust and were pleased with not only the dyno result, but also the new exotic tune that wailed like a trained singer at wide-open throttle, with no drone.

In Part 3, the Fabspeed/VAC cat-less headers released significant horsepower, but at the price of increased noise—lots of it—due to the cat-delete.  The show went from a Bocelli concerto to a head-bashing Slayer concert.  The aggressive rasp that started around 3000 RPM made the combo not very desirable for civilized cruising, but we'll admit it did sound good at WOT.

We could have installed catalytic converter-equipped headers from VAC and be fine, but there was  a significant cost increase, and a possible handful of ponies tucked away as well.  So, we decided to try another cat-back exhaust system by calling our friends at BimmerWorld, who pointed us to Magnaflow.

Before we get into our discussion, let’s be clear in pointing out that we feel both the Corsa and Magnaflow exhausts are quality systems.  Personally, I’ve tested Corsa cat-back exhausts on five different M3s, and all with favorable results.

Like-wise, I’ve tested Magnaflow systems several times in the past, including on a Mini Cooper S and Audi RS4—both of which yielded positive results over stock.  I’ve also used Magnaflow mufflers on some of my previously-owned cars, including a 338whp Porsche 951 as well as a 550whp E36 BMW M3 turbo.  Currently, I’ve got a custom 3.5-in exhaust on Project Supra that uses a Magnaflow muffler as well.

(Be sure to check out our comparison video on page 6!)


We ordered our Magnaflow exhaust system through BimmerWorld.  When a box like this arrives to your doorstep, it’s better than Christmas.


Magnaflow packages their exhaust systems well.  The company is also good about protecting the tips, which were heavily Styrofoam-packed as pointed out here.

Unlike our Corsa system, which connected to the stock Section 1 coming off of the headers, the Magnaflow systems replaces Sections 1 through 3.  What attracted us to this particular exhaust was the large center resonator, given our pursuit for greater civility while cruising.




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Monday, February 24, 2014 5:49 AM
The change in the X-pipe location (further back compared to the Corsa H-pipe) could explain power losses at high RPM.

In the MF in-car video section, was someone grinding something in the shop?

From inside the car, the MF does sound more civilized and streetable while the Corsa had more of a raw, uncorked 'racecar' sound both inside and out. From outside, the MF has the typical S54 buzzy/tinny "rasp" which could have been drowned out by the pure volume in the Corsa.

Good report!
Monday, February 24, 2014 6:59 AM
How do you feel about headers retaining heat exacerbating detonation? Has your tuner ever noticed such a thing? Tuners in the LS world have noticed this trend. I figure your guy has seen a slew of these engines and would be able to speak to the amount of ignition advance you car tolerated vs. others.
Pablo Mazlumian
Pablo Mazlumianlink
Monday, February 24, 2014 8:13 PM
Thanks for reading, guys!
@stuntman, yeah they were welding and some work 20-30 feet away on one of the race cars.
EDIT: Glad to hear the sounds came through the video because your assessment is pretty spot-on to how it sounds in person.

@Supercharged111, no haven't heard that. I guess I don't see how it would be an issue unless there was a lot of back pressure. Coatings and wraps are used extensively on race cars (although they use race fuel too, so less chance to detonate). I've had several exhaust manifolds coated without worry, and on hotter-running turbo cars, too. but I've also always "dipped" down the ignition timing right when boost/torque ramps up in my own turbo cars to play it safe on the motor anyway.
Monday, February 24, 2014 10:07 PM
I like my plastic components to remain intact, so I'm still a fan of coatings and haven't personally witnessed what I mentioned above, but I do like to poll other communities to see their experiences from time to time. It just seemed so weird when a few tuners spoke up on the matter, totally counter-intuitive to what is preached both here and in marketing.
Monday, February 24, 2014 10:24 PM
I don't know too much about LS engines, but I have a theory. The exhaust wraps/insulation will cause the header to get hotter. My theory is the heads have poor coolant flow, so the head gets hotter leading to the detonation. Just a thought. One thing those LS tuner guys can do is put a thermocouple on the head and measure the difference with and without insulation.
Saturday, November 21, 2015 3:30 AM
Hello im Diego of Peru. Last week buy a Magnaflow 16602 for my M3 E46 and he will install it this monday. Very interesting to read the articule but y have a doubt, in the test of bank that they do i see that these systems of leak throw minor quantity of hp that those that he declarates the manufacturer ( BMW M3 E46 343HP) These systems make it slower to the car. My aim is to win hp and good sensations. I did a good purchase? Thank you very much.
Pablo Mazlumian
Pablo Mazlumianlink
Saturday, November 21, 2015 8:13 PM
@Diego: you won't lose power over stock with the Magnaflow, but you won't gain a lot either. In fact, you won't gain much power with any cat-back exhaust without taking out the catalytic converters, or switching to high flow ones at least. I think you will like the exhaust. Let us know here how you like it when you install it.
Wednesday, November 25, 2015 8:23 PM
PAblo Thanks for your answer, today i install the Magnaflow on the car and everything is fine but i have a question please. The original system have ox¡ygen sensors, and the new magnaflow 16602 dont have the conector for put the oxygen sensor. which connect the oxygen sensors? magnaflow not have the connector, thanks a lot for your time.
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