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      03-06-2012, 05:48 PM   #1
Jon@Bimmersport Automotive

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OEM Exhaust mod - Which version suites you?

Over the past few weeks that is probably the question that has popped up the most. As some of you have seen we did another member RO_TURBO's E93 M3 with the "straight through" method. Just the other day we did the non perforated method on another member yoyoman's E92 M3. It is hard to compare realistically the difference between the 2 methods on the computer/speakers also given the cabin noise will be different between the 2 chassis. Luckily RO_TURBO has set up a meet to our fellow BMW brethren so we can see in person how they sound. For those who cannot attend, I am making this thread to help you out.

Straight through method:

This method completely bypasses the muffler system and is identical to running your car essentially without the muffler itself. We use existing piping from your muffler and re work it to be as straight as possible. We seal each chamber back up, weld it and paint/seal it.

Pictures of installation can be found here:
Straight through method

Video of straight through (left) and AA Signature (right):

Non resonated pipe method:

What we do in this method is cut open the centre chamber of the muffler which houses the perforated pipes and muffler baffling. What we do is cut out the perforated pipe and replace it with a solid traditional pipe and re pack the baffling. What this does is isolate the sound waves to channel through the pipes opposed to letting it getting absorbed or muffled (hence the name muffler).

Pictures to see the differences:

Here is a stock video taken at operating temp:

Here is a video taken at operating temp which is modded "non perforated":

My thoughts and input:

To be honest, nothing gets to me better than nice exhaust tips. I am not a fan of the stock tips seeing as how companies like Active, Eisennmann, Akrapovic, Meisterchaft etc. have products that look like works of art in my opinion, coupled with a nice diffuser it is almost perfection. However, not everyone wants the look, that sound, or paying that amount to have more appealing exhaust notes. For that market there are these methods.

Out of the 2, I prefer non perforated. Why? The tone of the exhaust is dancing on the fine line of classy, and down right aggressive. I met yoyoman coincidently the other day and asked what he thought, and he actually regrets not doing it sooner and came out exactly how he wanted.

I also noted that my 2 clients are of a completely different generation...straight through being younger, and non perforated being older (not saying your an old geezer Tim!). For some that info may help decide which may be more suitable for their needs/wants (some people aren't even sure what they want). On the other hand, I'm 24 and love the non perforated method keeping in mind daily driving.

Tech details: All pics and videos taken with Iphone 4s which is not bad, but i noticed each video sounds higher pitched and raspier than in reality. Each video was taken with the owner's consent.

If there are any questions or concerns please feel free to contact me either by phone 905 670 9200, email or PM.
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      03-07-2012, 04:57 AM   #2
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great review, too bad i dont have speakers here at work...

i will also do the non perforated version soon, also i will change the tips with custom 80mm single walled tips.

i also want it too loud, but i will an aggressive sound at higher rpms at WOT.
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      04-04-2012, 01:08 AM   #3
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Thinkin about doing the non-perforated mod also. There are smaller perforations in the other piping. Do you change those out too?
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      04-04-2012, 03:00 AM   #4

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I have had a Magnaflow system on my M3 for the last year, today I had the OEM mod done (non-perf) and I love it. I had both perf tubes cut out and straight pipes welded in its place. IMO it is perfect!!! IF cruising around, its quiet but once you hit the gas it sounds amazing.... Best part about it, there is no drone at all!!!!
BMC filter, OEM Exh Mod, ESS Direct Flash tune, flat black kidney grills, color painted front reflectors, LUX Angel eyes, -2012 SVT Raptor 4 dr -09 E90 M3

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      04-04-2012, 06:12 AM   #5
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Originally Posted by CCL16M3 View Post
I have had a Magnaflow system on my M3 for the last year, today I had the OEM mod done (non-perf) and I love it. I had both perf tubes cut out and straight pipes welded in its place. IMO it is perfect!!! IF cruising around, its quiet but once you hit the gas it sounds amazing.... Best part about it, there is no drone at all!!!!
+1. This. I'm 44 so I probably fall into the "old" category of people who mod exhausts. I hate stupid loud for a variety of reasons. But the non-perf mod is absolutely perfect. For me.
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      04-04-2012, 08:18 AM   #6
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I have to say that both sound really good, but the muffler delete would be for me if I had went that route

I agree 100% with you on the tips, need to be bigger and fancier. Stock they're nice but just really bland....
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Full Innotech Exhaust - DINAN Intake - IND Engine Bay Appearance - IND Hand Stitched Boot Covers - and much more....
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      04-04-2012, 05:15 PM   #7
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Just had this done (ACM version) and it's pretty bad ass. Definitely NOT stupid loud. It's not as loud as I thought it would be.
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