128i Magnaflow catback drone.

[munkie]

I had a MF catback installed yesterday morning. I'm happy with the system overall in terms of power and sound, but I'm surprised at how droney it sounds around 2k RPM. Also when in a higher gear on the highway and accelerating. Especially since most people commented on how quiet the system is and no drone.

I'm wondering if maybe something was installed incorrectly or if there are any adjustments I can make. I had it installed by a shop, the guy welded everything instead of clamping.

I've driven close to 100 miles, not sure if it will be any better once it breaks in? The sound right now doesn't seem worth the drone.

At this point I'm leaning towards putting the stock resonator back in and either going muffler less or getting something custom done by a nice shop. Even if I have similar drone with no muffler, at least it has that more "raw/rasp" sound.

Any thoughts from people who have it installed?

[Blau]

I've got the Berk axle back. Its a fancy muffler delete. I can tell you that it's droney AF around 2k.

Just down shift and give it the beans and it goes away.

[Yvrbmw]

Are you running a header as well?

I have an AA header and MF exhaust and I don’t find it drones at all. Volume is as expected, between stock exhaust and no exhaust. Definitely louder than my son’s 135 with stock exhaust too.

[munkie]

Originally Posted by Yvrbmw

Are you running a header as well?

I have an AA header and MF exhaust and I don’t find it drones at all. Volume is as expected, between stock exhaust and no exhaust. Definitely louder than my son’s 135 with stock exhaust too.

No headers, but I do have the euro intake and a silicone hose. I drove it again and Im getting used to it, but I do wish it was a bit more raw sounding (not louder).

Thanks for the replies fellas.

[patrickslit]

Just installed the same exhaust (MF 16525) and got my secondary cats removed. It is a bit drony at 2000-2500 rpms -- did yours get better?

[munkie]

Originally Posted by patrickslit

Just installed the same exhaust (MF 16525) and got my secondary cats removed. It is a bit drony at 2000-2500 rpms -- did yours get better?

I don't put a lot of miles on the car, but it does seem to be a little better than before. It used to bother me in all driving, now I only notice it when Im cruising in a certain gear and in that range.

Maybe I just got used to it, but it doesn't seem as jarring now.

In all honestly I picked up a really nice 135i N55 exhaust for $90 and I might put that in instead, I think having the "flap" is what helps with the low end drone. Trying to decide if I put the stock resonator back in or go with a straight pipe there.

I will say the car feels pretty quick with the MF exhaust, Im not sure if it's the weight savings or the fact that I have a software tune, but in general and especially on the highway it feels great.

GL!

[2tonik]

If you just have a drone, a quarter wave resonator pipe can be very effective at reducing sound pressure levels at a specific frequency range. For overall sound level reduction, Car Chemistry Inserts baffles can be mounted inside existing exhaust tubing. I did both to my AA header equipped 128i (the rest of the exhaust system is stock) and it brought sound levels down by about half (10dB reduction) - which is a massive improvement and very close to stock levels. I record sound for a living and have hypersensitivity and tinnitus, but thankfully my acuity is still good. But the hypersensitivity means I can't tolerate even slightly loud sound pressure levels.

Save your hearing! You can't get it back once it's lost.

BTW, What is loud to person varies with congenital hearing acuity plus how much hearing damage the individual has accrued over their lifetime. If you've been to a music concert with an arena PA system just once in your life you already have hearing loss. An individual with significant hearing loss is not going to be as bothered by droning at specific frequencies and/or overall high sound pressure levels - these are likely the folks who report that such and such exhaust builds are not too loud to them. If the car is too loud with a particular exhaust configuration, you need to quiet the car down in order not to damage your hearing.