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      09-24-2012, 03:12 PM   #1
Wrngway
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Drives: '11 328i Sedan A6
Join Date: Jul 2011
Location: D.C. Metro

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Another Active Autowerke E90 N52/N51 Review

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.

Last edited by Wrngway; 02-02-2018 at 10:29 PM.