Aside from a brief cup of coffee with a Kia Stinger, I’ve put an aftermarket exhaust on every single car I’ve owned. But what I look for, and the refinement I expect, is not an easy combination to find. Because the G80 M3 was so new when I received mine, it’s taken the aftermarket a little time to catch up and provide an exhaust I’d be happy with. I’ll save you the suspense by telling you I’ve essentially straight-piped my G80 M3’s exhaust with AWE’s track system. But how did I get here? I’ll explain, with some help from Tyler at TySpeed automotive.
What is up with the stock G80 M3 exhaust?
This generation of M3 is more refined than ever, and with good reason. It’s really a luxury car. Shhh don’t tell anyone ok?
But it is, and that means it’s quiet. That’s ok. I’m pushing 40, and if I wanted rowdy and raucous every day, I’d be in an Alfa 4C.
The luxury aspect of the car means that BMW’s goal in designing the exhaust system was to filter out everything, and then put only certain sounds back in. As a result, the (admittedly beautifully designed) single piece stock G80 M3 exhaust has not one but two resonators, along with a muffler. This is in addition to four catalytic converters and two turbochargers. The exhausts gas has a long way to go before it makes boom noises at the back.
Those resonators are the main culprit for the quiet sound, which is why simply replacing the stock muffler and keeping the mid-pipe yields less than desirable results.
To put some of that sweet six sound back in, BMW added valves into the rear muffler that open when the car is under certain conditions (i.e. full throttle), or Sport+ mode. This keeps it quiet when you want, and loud when you want, in theory. BMW has been adding valves into their mufflers for a long time. In fact, I believe the last BMW that came without valves in its exhaust was the E9X M3.
Stereo sounds
They also do something else – add in fake sounds through the car’s stereo. These sounds play at a different frequency than the normal radio, so they are always on, even if the radio is off. Pressing the M Sound Control button will turn this system off, even in Sport+. A lot of reviewers have knocked BMW for this, but I really can’t tell what’s real and what’s fake. I think the system is excellent.
As for aesthetics, the dumpy baby diaper look of the rear muffler is just sort of there, and has been on many generations of M3.
A final note on the stock system – it’s really light. I can bicep curl it. The E9X’s rear section alone was much heavier.
There’s nothing to knock against BMW here; they are selling a mass market car that must appeal to everyone. But even on its loudest setting, the stock G80 M3 exhaust isn’t very loud.
What makes a good aftermarket exhaust?
Now that we know why the car is so quiet, we can start to look at other aftermarket systems and weed some out.
Most aftermarket solutions replace both the rear muffler section and what’s called the mid-pipe, which usually takes out the two resonators. If you look at the stock unit, you’ll see what looks like a ‘true-dual” layout, something a V-8 might have because it has two cylinder banks.
BMW did it here because of packaging around the available M xDrive system and its front differential. Even my base and RWD Competition models receive this set up.
This is where the biggest difference comes from. Some systems, like the AWE, add a simple bend for an “X” configuration to the mid-pipe. Others, like Supersprint, create an H-pipe, or “single”, layout. Some owners have said that the single pipe provides better sound, so I asked AWE why they decided on an X layout. They informed me that in testing, the X pipe allows for a smoother, more refined tone, and I’m not going to argue that point because its true. It’s worth noting that the AWE midpipe only fits with the rear AWE unit, and no other makers.
The second component is the rear muffler. Almost every one offered is much smaller than the stock unit, and they are all valved to maintain the dual nature of the car. All but one, the AWE Track system I picked. No muffler there at all.
If I’m going to be driving around all the time with the valves open anyway (which I do), why do I need them at all?
The M Performance Exhaust, and paying for names
BMW started to recognize the opportunity the aftermarket provided with the E9X, and now have their own line of “M Performance” parts. I’m not sure why an $80,000 M3 doesn’t include such parts from the factory, but I digress.
The M Performance Exhaust
The MPE for the G8X platform features a unique center triangle shape cutout that no other system has. It looks cool, and matches the weirdness of the front, but also solves a problem no one asked to solve. M cars already have an exotic look with four quad tailpipes, dating back to the E46 days. This should be a law.
It also requires a unique rear valance and tips. All in, you’re looking at around $7,000 (that’s at cost, with no mid-pipe or install added yet), for a system that you’ll probably be disappointed with because it’s so quiet. That’s a lot to pay for a name.
Some systems, like Akrapovic, are made from titanium for additional weight reduction and are beautifully made. But again, we’re talking a lot of money for what amounts to metal pipes. I won’t tell you what music to like, nor what exhaust to select, but I find the Valvetronic to be the worst. It’s cheaply made and sounds raspy.
Why I chose the AWE G80 M3 exhaust
While AWE makes a valved rear section, I wanted more sound, so I chose the track set up and mid-pipe, which replaces the entire stock exhaust all the way up to the cats.
- It’s 22 pounds lighter than the stock unit (and 14 pounds lighter than Akra’s).
- Adds a minimal amount of power (3 hp, 5 lb-ft).
- Can have it with chrome or black tips.
- Adds a dummy valve to prevent a check-engine light, leaving the computer to think the muffler valves are still there.
- It’s well made, and goes together easily.
Make no mistake, these are basically straight pipes. But there’s still some control over the sound. The M3’s computer is responsible for adding that burble, and it only does it in Sport +. Selecting a lesser throttle response softens the tone a bit. And the M Sound Control is unaffected. Turning it off still produces noticeable volume reduction.
A note about the cats
If you want to remove the cats and make your car smell like farts, that’s cool. The AWE exhaust relies on the shop to cut the cats off the stock unit and bolt them up to the mid pipe. But you can work around that and remove them, while still having the pre-cats installed closer to the turbos. I saw no O2 sensors anywhere in the exhaust system that lives under the car.
I’m not your daddy or the police, but removing the cats is not the best thing for the environment, and only adds raspy volume to an exhaust. Do so at your own risk.
Working with Tyspeed for the AWE install
While not a difficult install, the job requires enough cutting and measuring under the M3 that I felt it wise to consult a professional. So I went to Tyspeed, located in Jackson, New Jersey.
Tyler, the owner and master BMW mechanic, was kind enough to make room in the shop for me for the day and allowed me to document the process, which you can watch below.
If Larry is the master of detailing, Tyler is the master of all things BMW-related. He knew the trouble spots, carefully measured and was in general a pleasure to be around, as was his entire crew. They were even kind enough to bring the stock unit back to my home later that evening.
I have my choices living in the tri-state area, but hands down, I’d only bring my cars here.
How to install the AWE Track Exhaust for the M3
I’ll let Tyler explain, but if you’re looking to do this yourself, know that there are a few items to look out for.
- The center chassis brace requires some finesse, but will fit perfectly.
- AWE provides a variety of bolt sizes with the system, as oppose to using just one or two. Keep your sockets handy.
- The valve motors have nowhere to mount to, so we had to zip tie them to the subframe. They feature beautiful machine brackets, but something more permanent than zip ties would be better.
- Wipe down the exhaust after install with brake cleaner to prevent finger prints being burned into the pipes.
- Measure!
Yea but how’s it sound?!
Like this:
After a few weeks of breaking in the exhaust, I couldn’t be happier. It doesn’t drone, it’s loud in all the right spots on the tach, and it provides an enormous POP from the 1-2 shift. The lesson here: don’t be afraid to delete the muffler on this car. I feel like I got my old friend S65 back, minus the higher revs.
Now about that wheel gap…
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