Well, I've searched and searched and haven't found any viable solutions to lowering the interior droning of the exhaust. I have a Stebro exhaust with is very similar to the Magnaflow, possibly not quite as loud, but very close. It has developed a drone that was not there when new. It's not horrible, but seems to hover around 75-80MPH, which is where I do as much of my interstate driving as possible. I want to reduce this noise before my next big road trip (if possible).

I leave my back seats upright and the boot cover in place, which does reduce the sound a little. I do not have a sunroof, so cracking the sunroof open is not an option, I don't want to have to crack the windows open while on the highway. I've heard that dynomat does not really help.
Any suggestions?

 

heard good reports on the dynamat product when I was worried about how loud my magnaflow might be, but it requires lots of tedious work removing seats and essesntially striping the car down to bare metal. Anyway, I gave up and learned to love the drone.. you really can get used to it. (if all else fails, earplugs that shooters use might help).

 

I've seen the earplug comments before and that is why I did not go with the Magnaflow. The Stebro is not THAT bad, but the droning does interfere a little with the tunes that are so necessary on a long trip.
The luggage might dampen a little noise. Anybody tried putting thick blankets in the back or anything else that proved successful at reducing the noise?

 

Hey Vince,

I went the dynamat route. It can be very costly if you have a shop do it. I would suggestion buying a big roll of fatmat (fatmat.com) It's pretty much exactly the same as dynamat but at 1/2 the cost. I got a 100sq/ft roll for $79 on ebay, it's about $99 on thier site. I didn't even use half of it, I'd get the 36sq/ft roll for about $49. It makes for a somewhat fun/mindless weekend activity. Your car won't be lexus when your done, but it does help. As for the labor, pretty basic the rear seat comes off easy, doesn't actually require any tools (do a search for rear seat removal, or PM me), once you pull out the seat, you just remove the carpet floor in the boot (pull it out) then go to town with the fatmat, all you do is take a big piece of paper, trace the area you want to cover, the cut that out and then use it as a guide for cutting the fat mat, it has an aluminiumish backing and then the sticky material on the other side.(actually a ashpalt like material (the smell goes away after about a day). Just lay the piece down in place and the use the roller they provide you to make it smooth. I got pretty carried away (it's easy when you have 100sq/ft of it. I ended up actually having a local shop do some of it (before i knew how easy it was) and it cost me $200 for them to put one peice of it in the back, and then one in each door (talk about a waste of money). It's well worth the effort/time, and like I said, with visions of a quieter mini in mind it is a very fun project. Like I said, if you want I can take some pics of my boot work, as for the doors, well even though it only involves a few screws to take off the panels, you'll have to use your imagination.

Blake

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2003 DS/W MCS -sport-premium-leather-r90's-pdc-v1-uuc ****-madness intake-magnaflow-ecu-pulley-and a whole lot of luvin!

 

There are several options/ideas-
First if you don't like the noise then don't add a header- it might/will make it louder!!
Second- look at the way the exhaust hangs or is installed and adjust it a little to make it resonate a bit less or move the tail pipes just a bit out further from the end of the MINI even a tiny bit will help. Make sure that all joins are airtight-no leaks- it leaks NOISE.
Seal up everything from the inside- no noise leaks- look everywhere for tight seals. Sound proof means air proof. Too bad you cannot get an odorless smoke bomb and put it into a bottle or can and set it off in your car to look for air leaks- talk to someone about this. You are looking for where noise can enter the car.
Third- sound deadening is important. Materials that are superior will help more than the average stuff that is cheaper. Anything will help like fatmat. I used Cascade Audio VB-max Adhesive backing-easily adjusted ($20 a sheet 12"x30&quotin my front doors for the stereo benefits. Dynamat extreme is also good. These materials are of high quality and are more costly.
Fourth and if all else fails-enjoy the louder exhaust and learn how to throttle to control the sound.
Fifth is you cannot stand the noise- get a good powerful sound system and enjoy the music.
Sixth if you can't afford the audio upgrade or don't like music- get the UUC exhaust. Call randyBMC
Enjoy.

 

IMHO, the droning that you're experiencing is probably the same type of droning that you'd experience with any aftermarket exhaust. the reason you are hearing it is partially because your exhaust system is "louder". But, more specifically because the piping that is directly underneath the passenger compartment no longer has as much sound insulation as the OEM system. This is usually accomplished through pipes that have shielding themselves. For example, go look at a large pickup truck with 3" stock OEM piping. not only does the stock muffler have more shielding and restriction but many of the stock OEM exhaust systems also have some sort of sound shielding on the pipes from the cat to the resonator(s), to the muffler(s). Personally, if you like the sound of your current exhaust setup when you stomp on the gas. I'd recommend trying to either replace or add your resonator and/or add another resonator/glasspack in it's place. Especially in the areas directily under the passenger compartment. The exhaust system should still be loud and deep. but, it should cut down on the droning you hear inside the passenger compartment. Just keep in mind that it will add some restriction to the overall system. But, if your exhaust piping is already bigger than stock it should be negligible... good luck!

 

I suppose it comes down to either doing something to eliminate the droning (attacking its source), or doing something to inhibit its path to the ears...

There a few good threads on MINI2, this one being the most recent:

http://www.mini2.com/forum/showthread.php?t=40868

 

Thanks for the idea Blake, I should try this, starting with lining the boot area, and maybe even underneath the battery, then if need be I'll put the stuff under the seats.

jimbo858 - The stock exhaust has no more shielding than this system. The Stebro (like the Magnoflow) does have a resonator underneath the passenger comparment and some sound may be coming from it, but the vast majority of the sound I'm hearing is coming from the rear, not from underneath the car (which is why the sound level decreases quite a bit with the rear seats up). Thanks for the idea, but I'll keep the system intact.

TonyB, thanks for the link.

 

Hey Vince,

Go for the boot first, I also did the area where the battery sits. The doors are a nice touch, when you close the doors they have a nice solid feel to them, after I/they did one of them I compared it to the untouched door and one of the doors felt like a door on a honda and the other felt like a german car. The reason why I didn't venture to the front seats is that you are getting yourself into a huge project it you want to start to remove the front seats, and everything else that goes with it. But I know alot of car audio guys that love that kind of stuff, for me removing the door panels was as far as I wanted to go. As for cheap materials vs. the expensive stuff, well, considering the fact that the car audio shop put dynamat in my car (as I watched) and then I put in the fat mat, I can tell you that it's the same stuff. I'm sure that people will try to tell you that dynamat is superior, blah, blah, blah, but hell, a "bulk pack" from dynamat will cost you $250 and comes with (9) sheets of 18"x32" material, where as the fatmat has a pack with (9) 18"x32" material for $49. Do the math. Even if there is a difference between the two, it not 5 TIMES better, I'll put money on that. I have both, and I can tell you the sound dampening I did with about $50 worth of fatmat was above an beyond more effective that what the shop did with over $200 worth of dynamat. Just my opinion.

Blake

 

Undercoating is another sound deadening idea that might be worth considering.
Maybe $150 to $180 to do the bottom side of a MINI. Trucks do it all the time.

 

Try this link:
http://forums1.roadfly.org/mini/foru...389&page=2

It's my write-up on a sound-deadnening/absorbing polymer material. You paint this stuff on metal surface, and it absorbs the vibration and quite your car considerably. I was annoyed by the loud noise with my helix exhaust, but I'm pretty happy with it, now that I used this quiet coat stuff to insulate my mini.

I recommend this to audiophiles as well, since it improves the sound quality and bass volume of the car stereo greatly.

Good luck,

kazu.

 

the BMP Exhaust has a muffler under basically the shifter, that did quiet my car down inside. When i leave my seats up you can't tell there is a different exhaust on there. Until you nail it. But cruising at freeway speeds, it is nice and quiet