[N52UNED]

'07 328i automatic sedan
Before install: 3IM, BPC Stage 1 tune, K&N/charcoal delete, Turner silicone intake.



I had a used Active Autowerke Gen 2 muffler that I picked up from a local-ish e90 forum member, installed yesterday. Here's my take on it.


** Is it Loud inside the cabin? ... Yes
(louder than music at conversational levels, and can still easily be heard over it loud --- not cranked though) ...

... I've viewed any and all videos I could, any threads I could find, and all said the same thing ... it wasn't loud inside the car, and that you really couldn't hear it ... BS.

Yes, there's videos of folks driving and you really couldn't hear the muffler ... however capturing the muffler noise is quite difficult. I tried a number of times with my iPhone and not once did it come through at actual levels. It was pretty much like the videos had. Unfortunately the do not accurately capture the sound level in the car.

Up until about 2k there's no denying that can easily be heard ... even to the point of not being able to be ignored. At 3k it gets a lot quieter, and it blends in with the engine noise ... so at that point, it comes across as a sporty car accelerating.

Even at idle you can easily hear it. Unless you listen to music loud ... it's there.


** Does it sound good ... Yeah.

On start up, you hear this nice deep bassy rumble; which levels off as a sporty rumble (again easily heard in the cabin). At 3k it sounds pretty sweet. It blends in with the engine noise as it accelerates quite nicely. At lower RPM's (500-2k) to me, it has too deep a tone. It's almost like, it doesn't quite fit the performance of the car. It sounds like a 300+ hp car. Almost muscle car-esque.

(Frankly, I feel like a bit like a fraud since is sounds mean but it really isn't. Plus my car is all stock, so it's not like it looks fast either).


** Does it Drone? ... Yes

Between 1500 and 2k there's a rather noticeable drone (deep droning sound) ... and frankly a bit annoying. When you're at and above 3k it still drones but the ring of the muffler mixes with the engine noise, but if you are easily annoyed by droning, it'll easily stick out.

According to a guy on another forum ... he brought the drone to AA's owner's attention, and the owner said that all performance exhausts drone between 1,500 - 2k RPMs. I also noticed that their website no longer says "eliminates drone" and replaced with "reduces/eliminates" drone.


** Is there a Performance Gain? ... Feels like it

AA has it @ about 1hp for (Daily Driver) Low RPMs ...
5k RPM+ Range ... 8hp
Average of about 5hp

These number seem pretty reasonable and fairly accurate. Although in the lower (Daily Driver) range doesn't really give any hp gain ... it does feel like it accelerates a bit quicker. It's almost like you can feel the car breathe a bit better. I'm not totally discounting the Placebo effect. But driving the same roads I have for the past couple years, it does seem to get to my "normal" speeds quicker.

AA did publish that you get the same amount of added torque (dyno sheet) ... honestly I don't feel any difference in torque really.


** Is there a Drop in Performance ... Feels like it

I've found it to bog a bit. This happens at times when you're turning onto another street (second gear) and the RPMs are down, when you give it gas it bogs. I will state, since I've done the K&N and silicone tube; I had noticed the same issue, but not as pronounced as it is now.


All in all ...

I'm of the belief that it's not a good choice for a "city" daily driver (with auto trans). Unless you're accelerating hard, it's fairly loud in cabin. Then there's the drone up until a bit over 2k; so if you're not someone who keep the RPMs at around 3k ... it can be a bit annoying.

Perhaps having an automatic transmission exacerbates these downsides ... but even in Sport and Manual modes, they're still there just muted a bit.

I'd say for a track car / majorly highway / where there's high speed limits and few stops ... it's cool. But for an in-town daily driver, I'd pass on it ... if you do, make sure to keep the stock muffler just in case.

[FlaPatsFan]

I have a 2011 328i E91...I started out with just the AA Gen2 Axel back and custom resonator and secondary cat delete. Loved it...mine did not have much drone and sound was great.

You need to give it a few months to break in, and it will. Depends how much you drive. Mine is not a DD. Drone should go down a bit. Sound will deepen a bit more.

I have since added AA catless ceramic coated headers and it’s loud! Thinking about putting secondary cats back in. But it added a lot more power, especially pulling harder thru mid range RPMs.

[N52UNED]

Originally Posted by FlaPatsFan

I have a 2011 328i E91...I started out with just the AA Gen2 Axel back and custom resonator and secondary cat delete. Loved it...mine did not have much drone and sound was great.

You need to give it a few months to break in, and it will. Depends how much you drive. Mine is not a DD. Drone should go down a bit. Sound will deepen a bit more.

I have since added AA catless ceramic coated headers and it’s loud! Thinking about putting secondary cats back in. But it added a lot more power, especially pulling harder thru mid range RPMs.

Mine is used so it should already be "seasoned" ...
Is yours a standard or auto trans?

I'd imagine the custom resonator may have helped as well.

Mine's a in-town DD

[FlaPatsFan]

Originally Posted by N52UNED

Mine is used so it should already be "seasoned" ...
Is yours a standard or auto trans?

I'd imagine the custom resonator may have helped as well.

Mine's a in-town DD

Ahhh ok, you would think it’s broken in then.

Mine is automatic, but I use the auto stick a lot. It sounds great with my set up and other performance mods. Look into a custom resonator or midpipe that may help. Some others can prob chime in on that.

[Biginboca]

N52UNED are you sure you got a “Gen 2” AA muffler? Cause I have one and your experience doesn’t sound like mine. Does yours have the little secondary drone chamber?

What you have described sounds like what people with the gen 1 described.

[N52UNED]

Originally Posted by Biginboca

N52UNED are you sure you got a “Gen 2” AA muffler? Cause I have one and your experience doesn’t sound like mine. Does yours have the little secondary drone chamber?

What you have described sounds like what people with the gen 1 described.

I'm guessing having a 6spd vs an Auto trans is a bigger difference than one would figure. At cruising speeds are your RPMs above 2,500?


It's this one ...



Not this one ...

[N52UNED]

Originally Posted by FlaPatsFan

Ahhh ok, you would think it’s broken in then.

Mine is automatic, but I use the auto stick a lot. It sounds great with my set up and other performance mods. Look into a custom resonator or midpipe that may help. Some others can prob chime in on that.

who did you get your custom resonator through?

[FlaPatsFan]

Originally Posted by N52UNED

who did you get your custom resonator through?

I have a local indy/custom muffler shop I go to. The guy that runs the shop is super knowledgeable and does great work. He gave me different options for my resonator based on what I wanted for sound. See if anyone in your area can recommend a shop. And not Midas or chain shop. Preferably a custom or performance shop.

[Biginboca]

Originally Posted by N52UNED

I'm guessing having a 6spd vs an Auto trans is a bigger difference than one would figure. At cruising speeds are your RPMs above 2,500?


It's this one ...



Not this one ...

Yes mostly above 2500 more like around 3k, and more like 3500 on interstate

[atmosphericM]

OP: The stock center muffler probably does a pretty good job of muting the engine noise, I would leave it alone.

IMO, this all comes down to personal preferences. There are plenty (the majority actually, it seems) here that love a loud exhaust and enjoy a muffler delete. They'll say that a even muffler delete isn't very loud or droney. Then they are guys like the OP here that think a simple axle back is a little too loud and droney. Different strokes...

Objectively, any exhaust mod is going to be noticeable and "loud" depending on the ears it falls upon. It's been shown that the stock 328i rear muffler is super quiet, so replacing it with anything at all is going to result in a good bit more noise, inside and out.

Looking at that muffler's size and design, I'm betting you're around BMW PE sound levels.. and yeah, one can definitely hear it.

Hate to hear about your experience, OP, but I suppose that's just part of the exhaust game. I've always been one to really want to hear an exhaust in person before pulling the trigger.. especially when the part costs over a grand (if not 4 grand). At least this was a, relatively, inexpensive experiment.

[atmosphericM]

To any reader that want's just "barely" more noise than stock, I'd suggest the BMW PE muffler (keep the center muffler, though). That, or a modified 135i muffler (if it's possible to make it fit).

[N52UNED]

Originally Posted by Biginboca

Yes mostly above 2500 more like around 3k, and more like 3500 on interstate

Yeah ... above 2500 it's the okay, a bit of a drone but nothing to whine about. 3k + it just blends in. It's just below 2k ... especially when coming off a stop. If you don't hit the gas and bring up the RPMs it's loud enough to be annoying. Since I live in a city (not metropolitan) there's lots of stop lights. Which is exacerbated due to all the Sr citizens who live in coastal FL cities.

[N52UNED]

Originally Posted by FlaPatsFan

I have a local indy/custom muffler shop I go to. The guy that runs the shop is super knowledgeable and does great work. He gave me different options for my resonator based on what I wanted for sound. See if anyone in your area can recommend a shop. And not Midas or chain shop. Preferably a custom or performance shop.

Where are you in FL (I don't mind driving a reasonable distance) ... I really like the idea of a custom resonator. Plus I'd like to delete my secondaries, unfortunately no one local will do it.

[FlaPatsFan]

Originally Posted by N52UNED

Where are you in FL (I don't mind driving a reasonable distance) ... I really like the idea of a custom resonator. Plus I'd like to delete my secondaries, unfortunately no one local will do it.

I’m in Sarasota. Wbu? Send me a pm and we can coordinate it.

[E91Swagger]

Thanks for the review, OP
Both Big and Fla have secondary cat delete and you don't. Could this be the reason for the drone?
Yeah, don't like drone

[Biginboca]

FYI I paid extra attention today. Cruising at 2500 my exhaust seems very quiet in the car but if I get on the gas at 2500 it gets loud. Like in 6th gear at 2500 if I go WOT it sounds kind of like a drone as it climbs slowly through the revs.

I have a loud intake so it’s possible some of that noise I’m hearing is intake noise also. Overall I feel the AA Gen 2 is an aggressive sounding muffler on the throttle but at steady speeds I can’t imagine anyone would have a complaint with it. Pretty surprised at your disappointment with it.

[N52UNED]

Originally Posted by Biginboca

FYI I paid extra attention today. Cruising at 2500 my exhaust seems very quiet in the car but if I get on the gas at 2500 it gets loud. Like in 6th gear at 2500 if I go WOT it sounds kind of like a drone as it climbs slowly through the revs.

I have a loud intake so it's possible some of that noise I'm hearing is intake noise also. Overall I feel the AA Gen 2 is an aggressive sounding muffler on the throttle but at steady speeds I can't imagine anyone would have a complaint with it. Pretty surprised at your disappointment with it.

What you mentioned is pretty much my experience. At about 2700 it's relatively quiet with a slight drone, but blends into the intake/engine noise well enough. Yes, when you accelerate it gets louder.

I do agree it's aggressive sounding ... and when you're on the gas it does sound nice.

My issue is really the sub-2k RPMs, it's much louder than I imagined ... too much so. Honestly that's the only real disappointment I have ... although it's s big one for me being it's an in-city DD. Frankly it's really because posting after posting folks have said that they really couldn't hear it in the cabin. I understand "loudness" a personal since, and 6spd trans are likely to have less due to shift patterns vs an auto trans ... but I feel those postings are understated. That's why I felt the need to post this review.

Instead of swapping it back out ... I'm likely going to follow FlPatsFan's lead and get a custom resonator. I figured I'd have to pay for the swap ... might as well put that $$ into a resonator instead. Plus the car does seem to perform a bit better outside of the bogging, but I'll just have to adjust my acceleration to compensate and stave off the bog.

[N52UNED]

Originally Posted by FlaPatsFan

I'm in Sarasota. Wbu? Send me a pm and we can coordinate it.

Other side of the state ... Palm Coast but Sarasota isn't out of the question.

Y'all seem to have all the speed shops over there.

[Phyrexia]

So what I'm gathering from all this is that the AA muffler with the stock center muffler is louder than the PE center muffler delete pipe and the PE muffler. Wow.

I wonder if the higher ratio rear end in Biginboca's car affects constant load at highway speeds enough to change the steady state characteristics of the exhaust note.

[N52UNED]

Originally Posted by Phyrexia

I wonder if the higher ratio rear end in Biginboca's car affects constant load at highway speeds enough to change the steady state characteristics of the exhaust note.

Yeah I've though of that ... perhaps I dismissed the idea too quickly. But from input from 6spd drivers, there's definitely a db difference in the low RPM area.

I really don't have any issues at highway speeds as the exhaust blends in the the engine noise well enough. It's bascially 1st and 2nd gear (under 40 mph) that is annoyingly loud.

Granted I've gone from a super quiet exhaust to an aggressive exhaust, so the db difference is likely influencing my comparison a bit.

[atmosphericM]

Do what you will but I'll be very surprised if any "custom resonator" makes it any quieter than it is currently. Look at the inside of the OE center muffler, it's perforated and packed. I could be wrong... glad you'll be the guinea pig.

But what I'm really confused by is that you'd want to get rid of secondary cats, which will only make things louder, if you're already complaining about the noise levels?

I'm thinking that the torque converter is leading to more noise in those lower RPMs, but I'm clueless as to exactly how those automatic transmissions work. Either way, yeah, most MT guys are never below 2000 RPM. MT N52's are suuuper slow down there...

[ktm137]

This:

Originally Posted by atmosphericM

Either way, yeah, most MT guys are never below 2000 RPM. MT N52's are suuuper slow down there...

I have the Gen 2 muffler on my '06 330i 6MT.

It _does_ have a drone below 2500 RPM. In general, I don't live in that RPM, as it is below 70 mph in 6th.

If I'm in traffic that can be annoying when speed drops below 70. This is one reason I'm finally getting around to installing my 3.64 final drive from an auto 330i - get the revs up at lower highway speeds. Crazy, huh?

As mentioned, even up to 2500 RPM it isn't bad at constant throttle - but stepping on it is noisy.

I will say With the 6MT, I like the exhaust for hearing the engine when doing heal/toe downshifts. Oh, and in parking garages.

I've considered sound deadening from time to time, but from reading, it is not likely to make a huge difference. If others have better experience, I'm sure we'd love to hear that!

Hope this helps!

Kevin M.