I am in the process of creating the quietest Mini cooper possible, due to a hearing disability (opposite of deafness). I have gotten tire noise to the point where it is no problem, but engine/exhaust noise are still louder than I find comfortable. Is there a way to make the exhaust much quieter than stock? I want to get the car as quiet as possible before adding sound damping and barriers...I would be knocked out to have a Lexus quiet Mini

 

You could try adding a resonator into the exhaust system. Or another one. I think it already has one, but it is possible to run more if it is too loud.

 

Ear plugs, couple of bucks for a bag of ten pair.

 

I'd love to hear how you got rid of the tire noise.

I've got the aft half of my S quite quiet, using Dynamat-type stuff and carpet scraps, but the road noise coming in around the doors seems to be hard to get rid of.

 

I am also very interested in how you "solved" the tire noise issue. And an extra resonator in the exhaust system could indeed help.

 

OK, You've got an interesting goal not many MINI owners even consider let alone concieve.

I think you have a base cooper. What year?

What tires do you have- make model and size?

What sort of quiet are you looking for?
Quiet from inside? Quiet from outside? Both?

Quiet like a Prius? Or just as quiet as a 4 cylinder Camry (probably similar to Lexus)? Each goal is different.

What are you doing for in dash radio or stereo? Are you using it much and what sort of stations or music do you play and how loud?

Got any sunroof? Cabrio?

What are you roads like? Smooth or not.

What is your weather like? Any snow or hot/colder weather?

How fast do you drive most of the time? Speed limit or faster?

How much on normal streets, or highways?

How much do you drive per year? Any long trips?

What is your budget for changes?

How many people ride with you most of the time? This determines load and may affect your suspension noise.

Certainly sound deadening will help a lot, put it in the doors, floor, kick and rear quarter panels, in the boot etc. Anywhere you can rip out the interior.

Undercoating-
Consider lizardskin SD- apply to under the car and to interior and floor areas for sound dampening and temperature reduction.
http://www.customrodder.com/tech/050..._undercoating/
http://209.85.173.104/search?q=cache...ient=firefox-a


Noise canceling technology-
http://www.halfbakery.com/idea/Noise...reo#1145322773

Noise Canceling speaker-
http://www.jellyfish.com/products/of...s/5014/4326665

The biggest help you'll get is from using tires that are as soft, pliant and quiet as possible- There are a lot of options so that is the most important place to start.

Stock mufflers are not generally going to add that much noise and you can suppress them further but it might affect backpressure and mpg or performance. Adding a resonator that is not too restrictive is possible as is a silencing tip.

Suspension needs to be softer so a good set of street coilovers is a possible option if your roads are very rough and bumpy. You can set dampening and rebound to your liking.

Don't add anything that would stiffen the chassis since that would transmit more road noise and shock to you.

Windows up, AC on, Sunroof closed or non existent. I wonder about sound deadening treatment for windows?

Window and door seams-
Extra rubber or foam (stick on) gaskets may help to seal potential points of noise entry from outside. As a car ages these rubber gaskets harden and crack or break and can be replaced or reinforced.

Realize that many of the sound deadening materials are heavy and add to the total weight of your car. Careful not to block up any drainage holes if you spray with undercoating materials.

 

You have a 2005 Base Cooper-

Some good tires to start with for comparison are:

Michelin Primacy MXV4 (Grand Touring All Season tire)
620 treadwear
Tirerack.com test-
http://www.tirerack.com/tires/tests/...ay.jsp?ttid=86
Ride comfort 8.05
Noise comfort 7.72

If you have stock 15x5.5" rims then-
185/65-15 $99 each H speed rated 20 lbs
195/60-15 $101 each H speed rated 22 lbs

If you have stock 16x6.5" rims then-
205/55-16 $123 each H speed rated 23 lbs

Bridgestone Turanza Serenity (Grand Touring All Season tire)
740 treadwear
Tirerack.com test-
http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=86
Ride comfort 7.89
Noise comfort 7.43
Consumer rating:
Ride comfort 9.3
Noise comfort 9.1

If you have stock 16x6.5" rims then-
205/55-16 $117 each H speed rated 25 lbs


Goodyear Assurance Comfortred (Passenger All Season tire)
700 treadwear
Tirerack.com tests-
http://www.tirerack.com/tires/tests/...ay.jsp?ttid=74
Ride comfort 7.59
Noise comfort 7.37
Consumer rating:
Ride comfort 8.8
Noise comfort 8.8

If you have stock 15x5.5" rims then-
185/65-15 $78 each T speed rated 18 lbs
195/60-15 $82 each T speed rated 19 lbs

If you have stock 16x6.5" rims then-
205/55-16 $104 each H speed rated 22 lbs

More narrow gives less rolling resistance and taller sidewall gives more comfortable ride and hopefully smoother over bumps- this helps the suspension.

If I had to choose from these two tires I like the Michelin Primacy MXV4 for being quiet even if it does cost more. Talk to Alex@tirerack.com for more info or suggestions.

You can modify by stages but start with tires first.
I'd leave the exhaust alone for now and stay away from being hard on the throttle. Do you have manual or automatic transmission?

Another option is a tailpipe exhaust tip silencer- various companies make them, check the tip of your exhaust and measure the opening- you'll need to match this. One idea is- Apexi Active tail Silencer:
http://www.autocarparts.com/part/1591/2/
You can also take the part to an exhaust shop and have them weld a tailpipe on your stock exhaust that will accept the silencer of your choice.
The Apexi ATS has a valve in it that adjusts and doesn't rob performance hopefully.

 

As to muffling the muffler, you can go a long way with Dynamat, some carpet scraps, and some rubber sheet.

I've done the following - the Borla muffler on my S is much less noticeable inside the car:

- a sheet of soft 3/8" rubber under the floor of the boot, on top of the stock under-carpet mat. Sourced from www.mcmaster.com or locally.

- a lot of road and muffler noise comes in via the thin plastic tail-lights and into the car. I used Dynamat where I could reach sheet metal inside boot and the rear stashes, and filled the remaining volume in the stashes with carpet scraps cut to fit.

- Use Dynamat and carpet scraps on the inside of the sheet metal of the boot hatch, as noise gets in through there too.

- Carpet the entire car and the backs of the rear seats. The thickest sound-absorbing carpet mats are available from http://www.lloydmats.com/heavyweight_features2.htm I also cut 3/8" under-mat rubber mats for the front floor.

As to tires, I'm using what are very quiet tires on smooth new pavement, but are remarkably noisy on Oregon's studded-tire-chewed highways. Only cure I've come up with is putting lots of sound absorbent stuff around the car.

 

I think you have a base cooper. What year?

2005 cooper, Not an "S"

What tires do you have- make model and size?

Falken 912 195/55-16

What sort of quiet are you looking for?
Quiet from inside? Quiet from outside? Both?

Quiet inside the cabin

Quiet like a Prius? Or just as quiet as a 4 cylinder Camry (probably similar to Lexus)? Each goal is different.

4 cyl Camry would be fine, High end Lexus would be even better (let me dream)

What are you doing for in dash radio or stereo? Are you using it much and what sort of stations or music do you play and how loud?

Stock base stereo, i always have it on, no louder than a typical conversation.

Got any sunroof? Cabrio?

Sunroof

What are you roads like? Smooth or not.

Roads are decent, but some can be a little surly.

What is your weather like? Any snow or hot/colder weather?

Souther PA...midatlantic...a little bit of everything.

How fast do you drive most of the time? Speed limit or faster?

Speed limit or +5

How much on normal streets, or highways?

Even split, I will take a longer route to ride on nicer roads.

How much do you drive per year? Any long trips?

10,000 I am limited by my disability to 2-3 hours max, even an hour can be hard...quieter car would make a big impact on this.

What is your budget for changes?

Starting with $1000

How many people ride with you most of the time? This determines load and may affect your suspension noise.

one passenger...maybe a large dog.



Noise canceling technology-
http://www.halfbakery.com/idea/Noise...reo#1145322773

Noise Canceling speaker-
http://www.jellyfish.com/products/of...s/5014/4326665

Does noise canceling reduce sound pressure, or fool the brain? I can't fool the disability, sound pressure is the enemy. I am guessing it is a simple phase reversal with summing of mono signals?

The biggest help you'll get is from using tires that are as soft, pliant and quiet as possible- There are a lot of options so that is the most important place to start.

The Falkens have really helped after removing the GY runflats.

Stock mufflers are not generally going to add that much noise and you can suppress them further but it might affect backpressure and mpg or performance. Adding a resonator that is not too restrictive is possible as is a silencing tip.

I would love to hear more details about this, I am very mechanically inclined, but not much of a grease monkey...yet!

Suspension needs to be softer so a good set of street coilovers is a possible option if your roads are very rough and bumpy. You can set dampening and rebound to your liking.

Again, would love to hear more about this, brands or links?...

Don't add anything that would stiffen the chassis since that would transmit more road noise and shock to you.

No problem, i am not going after any after market performance enhancers

Windows up, AC on, Sunroof closed or non existent. I wonder about sound deadening treatment for windows?

I have been a windows up AC guy for 10 years since the onset of hyperacusus/tinnitus, and yes, this is good advice!

I will be going to sound barriers and sound deadening after the engine/exhaust are quieted to the point that they can't go further, or take me much below 115hp, I don't want a quiet Yugo when I am done


Thanks for the ideas, would love to hear more details about resonators (where to go, approx $, brand...etc)

Ear plugs are not an option (that would be easy), when you block out all the environmental sounds (radio a little wind sound) then all you hear is your ears ringing like made...then the fixating starts!


When I get to the sound deadening there will be a pro recording and measurements (scientific and subjective) to report to the group. Paul from cascade audio liked the idea of the project and said he would help out...so it looks like cascade will be the audio deadening.barrier of choice.

 

At this point I would concentrate on sound damping. I had similar issues with my other car (Corvette) with both exhaust and tire/road noise. I completely covered the rear tub with Damplifier and it helped tremendously...

http://www.secondskinaudio.com/vibra...damplifier.php

 

OK, thanks for all the information. I have some idea of what you want to do.

OK on the tires for now.
Falken 912 in 195/55-16 is OK. Moderately good on being quiet.
Use tire pressure slightly on the lower side about 33 psi is OK front and rear.
Higher psi gives slightly firmer ride.

Later then you ever change tires you can consider those I mentioned-
205/55-16 is OK size. 195/55-16 is a good runflat size but very limited selection of tires for regular MINI use.

I would expect a bit of improvement if you did switch tires someday but given your budget there are other things to work on first.

You can check out the Apexi ATC silencer for the exhaust- contact vendors and measure your exhaust tailpipe to check for options on fitment. Ask the vendor if it would help with a stock exhaust or not.

Aftermarket exhausts are not going to be more quiet than stock.

Best bet is adding sound deadening, sound proofing, or sound absorbent materials-

Consult with-
http://www.asiproaudio.com/soundproofing_material.htm
Ask them what can be added to carpet/floor, headliner, A and B pillars, Doors, fender panels, rear hatch or windows to help reduce or absorb sound. Besides a layer for the floor you can add another layer of material or carpet pads, same multiple layer approach to any panels or doors.

Sound deadening materials-
While Dynamat and others are less expensive I have Cascade products myself and like them (used VB max), see
http://www.cascadeaudio.com/car_noise_control/index.htm
Ask them for any help and advice, be creative.
Consider gasket material if needed to help with any gaps for air tight seal-
http://www.cascadeaudio.com/car_nois...eting_foam.htm
I wonder if AC Comp would be worth the expense for you-
http://www.cascadeaudio.com/air_craf...se_control.htm

After the sound deadening changes then later you can look at suspension.
First option would be Koni FSD shocks-
http://www.outmotoring.com/mini-coop...per_fsd_shocks
$660 plus labor. You keep your stock springs and just change shocks. Self adjusting to your driving.

Next would be coilovers like-
http://www.outmotoring.com/mini-coop...ooper_coilover
Koni Coilovers about $1300 plus labor, these are adjustable.
Or these- check with vendor on how smooth thay would be for street-
http://www.txwerks.com/servlet/Detail?no=116
$1895 a set plus labor.

 

Thanks for all the advice.

Is there reason enough to still look at adding a resonator to my stock non S 2005 cooper (5 sp), or just focus on the sound deadening and barrier which will mitigate road noise and engine noise both?

For the people that asked, the reason I did not use vernacular like "solved" or "got rid of" is because it is to the point where it is "not a problem" as I suggested, on decent roads the Falken 912 are barely perceptible, on crappy roads there is still tire noise, but I don't think the best of tires will quell noise from truly bad road surfaces. I am guessing a smaller diameter wheel with greater tire volume and a tire with the quietest ride would reduce road noise more, but I am thinking that putting my $$$ toward sound management is a better direction at the moment than increasing tire air volume and searching for holy grail tread patterns and rubber compound, I exhausted the search feature on the forum to find at a certain point people can't agree on the quietest tire. Edge racing recommended the Falken 912 as a very quiet tire, they are far quieter than the run flats were.

thanks again!

 

Well,
I just picked up my cooper from having Cascade audio treatment installed by a local car audio installer V-Max, VB-3 and VB-4 . I appear to have made no progress toward my goal of getting my Mini as quiet as a Lexus (I am now moving the goal posts). I will conduct some more measurements and listening later tonight when the roads clear, but at the moment i cannot hear a difference while driving and the Radio Shack meter is showing somewhere between no change and maybe 1db, this is using both a and c weighting. The doors do feel heavier and sound more solid when the door is pushed shut, but that was not my objective and i made that clear to cascade and the installer, strictly DB reduction.

I need to make some real progress, my girlfriend's 2008 Jetta is 20db quieter at idle (like, what I hear continuously when sitting in city traffic). I think the low bass drone is a result of the Mini Cooper (not an S) exhaust.

I really need some solid proven advice on reducing the noise at the source and not trying to stop noise with sound barriers. Can a resonator do the trick, if so, what diameter and length is best to reduce as much of the deep drone as possible?

What i have learned so far is the best way to get a quiet car, is to get a car that produces as little noise as possible in the first place...I am guessing sound reduction materials work more for cars that were poorly sound proof from the factory. I will report after I finish the "before and after" 31 band analyzer at 50mph test.

 

I have an MCS; I’ve had good results with sound deadening materials unlike your experience. Take a stroll through my gallery for some background. For exhaust noise barrier placement, the rear hatch door and backside of the trim, double shroud the backs of the tail lights, the center channel and fire wall benefit from dual applications of both viscoelastic and thermal barriers. It is surprising how much exhaust noise is generated in the fore section, and how much enters through the shifter box.








Place a blanket over the vent panels in the rear boot for an easy barrier application.

To suppress the noise source, replace the smallish OEM resonator with a Hushpower II or Magnaflow 5X14, and add a Vibrant 3.5X18 behind the center bracket.




The Vibrant's 3.5 inch OD allows ample clearance for the heat shield, but its 2.5 inch core doesn't provide much room for packing material. A more effective muffler for this location, and your application, would be a Magnaflow 4X18 with a 2 inch core. The dowside is a larger body OD requiring bending of the exhaust tubing to fit without contacting the heat shield.

 

If you truly have a medical issue with the noise, the MINI is the wrong car for you. A Lexus-quiet Lexus would be more realistic.

 

I truly have a medical disability, that is not a question I am posting at this forum. People who have a disability often try to take back as much as they can of what has been lost in life, the joy of driving a sporty car is something I enjoy and want to take back...so I persist with not simply laying down and assuming loss, like some would assume should be the best option. A lexus is simply not in my budget after medical bills from my disability, nor my interest in driving attitude.

We sent people to space, I think we can quiet a fairly common car...I really appreciate the constructive helpful responses I have gotten from the majority of this forum...Keep those noise reducing hints coming!

I think the exhaust is a good place to center my attention, my spectrum analysis showed that 20hz-220hz is where my cooper has the most sonic energy, above 500hz my cooper is much like other cars I have owned and not a real problem. I think managing sound before it hits the cabin is the best approach at the moment.

 

Thanks for your post and pics! There is some debate between Cascade and the installer as to the amount of material used, the placement of the VB-3 and VB-4 barriers and the difficulty/feasibility of the install that Cascade is suggesting. I feel like I am watching a game of ping pong that I accidentally bet $ on...

I am trying not to be too slow on the uptake about the exhaust, but I am just now learning the parts of the exhaust for this project. Can I go to a big chain muffler shop and get this stuff installed, or do I need a specialty shop?

I will try to post some pics of the Cascade install to show was was done, the shifter hump was treated with the VB-3, but again cascade wanted everything seam to seam with barrier only materials on the floor to firewall (no simple butyl deadeners), but the installer felt it was too difficult on a Mini Cooper to achieve this ideal.

 

It is a little thing, but make sure you drive with the back seat up. It makes a big enough difference that I drive with it down just to hear more sound. Good luck with your quest.

 

Note the most recent issue of Modern Mini has a section on sound deadening as part of their series of articles on improving the sound system.

Murph

 

Well I have found a solution to my problem, now I have super quiet road noise on all roads and very hushed exhaust, I also picked up 110hp!! The solution? I got a 2004 BMW530i ...Cooper is up for sale. Loved the Mini, but not compatible with my disablity, and The installer/Cascade audio products fell short (less than 1 db reduction was measured overall). It was worth the effort to learn. The lesson here is get a guarantee of decibel level reduction from sound deadening products/installers, or walk away with your $$$ in hand. Sound reduction is never subjective, it is measurable with a simple radio Sack decibel meter, again, no guarantee? just walk away...lesson for all who read this. The second installer, one that Cascade recommended, would not back up the sound barrier/deadening product and installation with a DB reduction guarantee (not even 1 lousy db!), Cascade audio would not give a guarantee either..game over!

In the future people who install sound deadening product should measure at idle and 50mph (same stretch of road for before and after), both DBa and DBc, then measure after installation and give results to the forum. Your doors will sound tighter, your stereo will rattle less...but stories about how the car "sounds quieter" are meaningless and lack veracity without the accurate db data to back up the hype...my readings?

before:
70dba 50mph
92dbc 50mph

84dbc idle

After:
70 dba 50mph
91 dbc 50mph

84 dbc idle

Thanks for all the suggestions along the way!

 

Sorry you had to give up the cooper, but no doubt you tried to make it work. Either way, your efforts have given me a good education in the art and science of sound deadening.

 

In theory, active noise cancellation SHOULD drop the energy level in a car in a measurable way, and not simply "fool the brain". Practically, it will alway "miss" being an exact opposite of the phase of the noise it is trying to cancel. The best analogy would be in a wave pool - if you had two wave generators at opposite ends of the pool making the exact same size waves 180 deg. out of phase, the pool would look calm. If you were in the water, you would not be influenced by either set of waves. Practically speaking, the sampler which detects the noise to be cancelled would always be reacting a little behind the real noise, and would probably turn the "pool" into little choppy waves, but not pure calm waters.