[Wrngway]

I thought I'd post my thoughts on the Active Autowerke N52 exhaust after having spent a couple days with it now. My car has the SULEV N51 engine. The exhaust system is a little different than the ULEV N52 car. It effects install, but the system sounds and acts the same once on.

It shipped from AA to northern Virginia in just a couple days, so I guess I was one of the first to get my hands on it. Packaging was excellent. The exhaust was bubble wrapped within an inch of its life and the box was also filled with paper, so it wasn't going to move around. It arrived in perfect condition.

It really looks like a work of art. Well constructed with a beautiful chrome finish. The tips look amazing and are finished off with an AA logo. They're adjustable in and out with a 6mm allen wrench. Also attached is a small plate or badge if you will with a serial number and AA name and logo. Most people will never see it once installed, but it's a nice touch that just shows some thought and care went into it.





Directions were included, but they turned out to be specific to the N52. The adjustable hangers were in a second bag colored blue so you don't accidentally throw it away with the packaging.

My install was done by Green Motorsport in Springfield, VA. They're an AA vendor and did a very good job after being thrown a curve ball of having to deal unexpectedly with the N51 differences. In the N51, the section after the secondary cats runs the same route as the N52. That section in the N52 is made up of two primary parts...the resonator section and the rear muffler section. In the N51 it is all one piece. The OEM pipe after the resonator was a slightly larger diameter than the N52. This means that, to install it on an N51, the clamp section on the AA exhaust will need to be trimmed off and the exhaust welded on. Here are some pictures of the completed install.







Now as to how it sounds. My OEM exhaust was near silent. As soon as you start the car the difference is noticable. Idle is louder and mellow. I haven't listened outside the car while its in motion, so I can't comment on how that sounds yet.

When cruising, you can hear the growl in the background and most of the time it isn't intrusive at all. When accelerating, it's loudest between 2,000 & 2,500 rpm where it does get a bit boomy. It's hard to describe, but I'll try to throw up some videos. It quiets down again above 3,000 rpm. It has a nice sporty note to it. Cruising up to 55 mph it isn't too loud and is pretty refined. Light to moderate throttle putting the engine under load at high gear will bring out a louder tone. That'll typically be when going up a slight incline in 6th gear (automatic trans) at around 60-65 mph. Any additional noise goes away when you take your foot off the throttle. Shifting to 5th raises rpms above 3k and it quiets down immediately.

My thoughts overall....Excellent build quality and well thought out. Outside the rev range described above, the sound is sporty, mellow, and refined. Betwen 2-2.5k rpm it's noticeably louder when under load. It doesn't really bother me, and if you prefer your car "church sermon" quiet, you probably won't be buying this anyway. With my wife and her preference for Toyotas on the other hand, I may have to downshift occasionally on the highway.

Sound is subjective. I'm going to follow up with a post containing some videos where I try to capture these conditions and you all can make your own judgement.

[Wrngway]

So, here are some vids. Most of what I see on youtube are cars under full throttle acceleration. Most of us don't drive that way most of the time, so here's a bit of what you might experience on a day to day basis.

Some sound is under 140 Hz. Listening to this on your smart phone won't work. If you have a system with a subwoofer, that's best. I'd also recommend turning the volume up a bit louder than you'd normally have it to get a good idea of how it actually sounds.

First video includes idle and rev:

Here's a normal take off from a light onto a back road. Windows are down during first half. Up and in DS during second half. The tone is a little louder than what you'll hear. My cell phone mike makes things sound a bit tinny:

Here are a couple of videos cruising on the highway. Keep in mind the speedo reads 4mph fast. The second video starts with accelerating from the on ramp.

[upstatedoc]

thanks for taking the time to do this.

[SflBimmer8484]

[Eric in SD]

Nice review and write up. Photos and videos too, very cool! The AA exhaust looks like a good alternative to the PE.

Have you heard both the AA and PE exhausts in person? If you have, can you comment on how they differ in sound?

[Wrngway]

Originally Posted by Eric in SD

Have you heard both the AA and PE exhausts in person? If you have, can you comment on how they differ in sound?

Maybe someone will correct me if I'm wrong, but I believe the PE includes a midpipe too. So the PE replaces the pipes just past the secondary cats and replaces the resonator as well. The AA exhaust attaches just aft of the stock resonator. That's part of the reason the PE is more expensive.

I've only heard the PE in video sound clips, so it's hard to compare the two. It's probably, IMO, one of the best sounding exhausts out there from what I can tell. I just couldn't make a case for spending more for such a minor performance improvement.

I didn't mention performance in my review because I really can't tell the difference. Part of the problem there is that it just got so much cooler and dryer recently, so the car already feels like it's gotten a boost. I think BMW advertises 6 hp for the PE. Andrew has said they're looking to do a dyno in their shop. There may be some increase there. There is a weight reduction of around 19 lbs though, so that'll help!

[Phil325i]

Originally Posted by Wrngway

Maybe someone will correct me if I'm wrong, but I believe the PE includes a midpipe too. So the PE replaces the pipes just past the secondary cats and replaces the resonator as well. The AA exhaust attaches just aft of the stock resonator. That's part of the reason the PE is more expensive.

Not necessarily. It depends on the particular engine and the market. P/E for most US cars seem to get the full cat-back system, but in Europe muffler only (axle-back) is the order of the day for many engines, because of emissions sensors and associated wiring plumbed into the mid pipes...

P.S. Personal view, but after the P/E, this AA system sounds tame.

[Eric in SD]

Originally Posted by Wrngway

Maybe someone will correct me if I'm wrong, but I believe the PE includes a midpipe too. So the PE replaces the pipes just past the secondary cats and replaces the resonator as well. The AA exhaust attaches just aft of the stock resonator. That's part of the reason the PE is more expensive.

You are correct, for the 328i in the US, the PE replaces everything past the secondary cats, including the resonator. But I think the PE for the 128i only gets the muffler and retains the resonator. Euro applications are different too.

It would be interesting to get the opinion of someone who has heard both exhausts side by side, from outside and from inside. It is impossible to tell from a video what the "live" sound is truly like. The AA exhaust seems to be very good quality, and a better value, plus, like you said, has a more of a weight reduction as a bonus. It would come down to the sound for me to decide if the extra cost of the PE was worth it.

[maf330xi]

Originally Posted by upstatedoc

thanks for taking the time to do this.

+1

Sounds great!

[just4kickz]

can you do a cabin windows up/down run up to like 6k rpm? tbh i think its only marginally louder, but it might just be because its video. really curious as to how this sounds in real life.

[Wrngway]

Originally Posted by just4kickz

can you do a cabin windows up/down run up to like 6k rpm? tbh i think its only marginally louder, but it might just be because its video. really curious as to how this sounds in real life.

I'll see what I can do. The volume is really situational though. I've had some loud exhausts on previous cars and stock on the e90 328i is near silent. This is somwhere in between.

It's loudest when accelerating slowly through 2-2.5k rpm using low to moderate throttle. Above 3k you get a nice sporty growl. It's louder than stock, but not so loud it would really bother anyone. You'll also hear the exhaust better with the windows up as it isn't competing with wind and outside noise.

Accelerating using more than moderate up to WOT you go through 2k rpm quickly so you get a relatively even noise level up to redline. Again, I wouldn't call it loud, but you'll definitely know it's there.

If you go back and listen to the videos, make sure your volume is turned up somewhat. They're quieter than what you'll hear in person.

The more I drive it, the more I like it.

[SavvyByNature]

+1 to what Wrngway said. Also, if you have a Tune w/ the 3IM, it smooths things out A LOT!!! It doesn't have the hp/tq dips anymore that you could feel on acceleration.

[Sseedubbin]

very thorough review

[StealYourFace]

Nice- I really like that exhaust.

I would get rid of the res to really perk it up.