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      07-19-2020, 12:08 PM   #1
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AA Gen 2 Exhaust drone?

I just installed AA Gen 2 exhaust (muffler). I am having lots of drone in the cabin from 1200 to 2500 rpm.

My exhaust setup is: Stock cats (headers), AFE race pipes (replacing secondaries), stock resonator, AA gen 2 muffler.

Is this normal?

Edit: Drone was caused by exhaust leak on one of the clamps.

Last edited by W37V; 11-09-2020 at 09:13 AM..
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      07-19-2020, 12:59 PM   #2
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I had the same issue. I had to take mine off after a few weeks.
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      07-19-2020, 02:02 PM   #3
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Quote:
Originally Posted by Marc81 View Post
I had the same issue. I had to take mine off after a few weeks.
I can see why. The frequency is causing some interior rattles which were not there before. Music and AC noise reduced the drone, but it’s still a bit too much.
On the separate note, there is definitely few hp freed up with this exhaust.
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      07-19-2020, 02:12 PM   #4
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This is surprising to me. I have a similar set up (almost identical except I have AA catless headers) and don’t notice any annoying drone. I really don’t spend time in that rpm range though I’m usually around 2500-3000 rpms when I’m cruising maybe that’s why. I find that muffler very quiet cruising in the 3k to 4K range btw. (That’s my highway rpms range.)
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      07-19-2020, 03:16 PM   #5
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I've read that the muffler needs to exit outside the rear bumper , if not it will resonate under the car. I read this after I removed and sold mine.
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      07-19-2020, 03:20 PM   #6
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Quote:
Originally Posted by Marc81 View Post
I've read that the muffler needs to exit outside the rear bumper , if not it will resonate under the car. I read this after I removed and sold mine.
Mine does exit behind the car and I haven’t noticed the issue. Maybe it does matter?

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      07-19-2020, 03:38 PM   #7
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Quote:
Originally Posted by Biginboca View Post
This is surprising to me. I have a similar set up (almost identical except I have AA catless headers) and don’t notice any annoying drone. I really don’t spend time in that rpm range though I’m usually around 2500-3000 rpms when I’m cruising maybe that’s why. I find that muffler very quiet cruising in the 3k to 4K range btw. (That’s my highway rpms range.)
Oh even for seconds you are in that range, you would notice it.
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Originally Posted by Marc81 View Post
I've read that the muffler needs to exit outside the rear bumper , if not it will resonate under the car. I read this after I removed and sold mine.
I had my father drive the car while I listened. Muffler is very quiet even under load. It is 10x louder inside of the car than outside. Outside is nice deep sound. Not racy at all. Almost like BMW PE, but not quite (BMW PE is the best sounding exhaust for N52). However, on the inside of the car sound is different story. Sound causes everything to rattle and is extremely loud. Lots of drone. Almost unbearable.

I will jack up the car to see if any of my clamps are loose or if there is anything touching. I do have my tips outside of bumper, but maybe they are too far out.
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      07-19-2020, 03:39 PM   #8
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Quote:
Originally Posted by Biginboca View Post
Mine does exit behind the car and I haven’t noticed the issue. Maybe it does matter?

Yours are actually closer to the bumper than mine.
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      07-29-2020, 01:34 PM   #9
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So after few hundred miles, it seems like the exhaust is quitting down. I did not see any leaks or anything touching.

Since I have AFE race pipes, which do not use transmission support, I might switch to supersprint race pipes for just in case.
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      07-29-2020, 01:59 PM   #10
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I thought the AA2 was supposed to be a lot quieter with that secondary chamber.
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      07-29-2020, 05:49 PM   #11
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Quote:
Originally Posted by bluewater328 View Post
I thought the AA2 was supposed to be a lot quieter with that secondary chamber.
I don’t think it’s quieter it just doesn’t drone around 3k rpms. It’s basically a straight through with a resonance chamber to quiet the sound down at a certain frequency which for me seems to be in the ~3k rpms range
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      07-29-2020, 05:59 PM   #12
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Quote:
Originally Posted by Biginboca View Post
I don’t think it’s quieter it just doesn’t drone around 3k rpms. It’s basically a straight through with a resonance chamber to quiet the sound down at a certain frequency which for me seems to be in the ~3k rpms range
Wish there was a way to truly have a A/B test of a few exhausts. There are a lot of clips out there, but with different audio (mostly shitty phone audio). Need a couple of different setups with a single constant audio(/video) source. ie. Good reference mic setup that's used for all comparisons at the same location (or at least conditions). Side of the road in one wooded area would be different from side of the road in the city or flatlands, or inside/outside a garage, etc.


Would love to see how my Magnaflow compares to the AA R2 or BMW Performance.
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      11-09-2020, 09:12 AM   #13
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Quote:
Originally Posted by W37V View Post
I just installed AA Gen 2 exhaust (muffler). I am having lots of drone in the cabin from 1200 to 2500 rpm.

My exhaust setup is: Stock cats (headers), AFE race pipes (replacing secondaries), stock resonator, AA gen 2 muffler.

Is this normal?
Just to conclude this. I actually had an exhaust leak on one of the clamps. Once I took care of it, drone was gone.
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      11-09-2020, 11:29 AM   #14
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Quote:
Originally Posted by W37V View Post
Just to conclude this. I actually had an exhaust leak on one of the clamps. Once I took care of it, drone was gone.
Clamp right after the resonator?

So tightening it down cured it completely? or just sound is more tolerable in that range?
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      11-09-2020, 05:18 PM   #15
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Quote:
Originally Posted by bluewater328 View Post
Clamp right after the resonator?

So tightening it down cured it completely? or just sound is more tolerable in that range?
Correct, clamp behind the resonator. It quieted down the note inside of the cabin. Drone is much less - very tolerable. To be completely honest, I can’t say that the drone is 100% gone.
Also, since my exhaust is made of pieces and is missing transmission brackets (I have afe pipes), I wouldn’t be surprised is what is contributing to drone.

I’m tempted to get supersprint pipes as they retain use of the transmission brackets so I can test my theory.
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      11-10-2020, 07:22 AM   #16
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Quote:
Originally Posted by W37V View Post
Just to conclude this. I actually had an exhaust leak on one of the clamps. Once I took care of it, drone was gone.
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      11-10-2020, 08:02 AM   #17
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