I've been working on quieting my car without paying a small fortune for it. A specific problem I've been working on is getting rid of road-roar; here in the northwest and in ski country where studded snow tires are allowed, the surface of many older roads is as coarse as frozen gravel, due to damage from the studs.

Whenever I drive on such a road, the noise from the tires on these coarse surfaces is loud enough to almost drown out the radio - like a pink noise generator with the gain up high. I call this noise road-roar.

I first bought the thickest carpet floor mats I could find - from Lloyd's Mats. I highly recommend these, and they soak up a lot of high-frequency sound, but they didn't do enough for the road-roar.

My second step was to dynamat the floor of the boot, using generic damping products from McMaster-Carr and Home Depot. This helped, but was clearly not the primary source where the noise was getting in. I next fit a couple of pieces of thick carpet in the area inside the taillights and boot cubbys, as a lot of exhaust noise gets in there, but it wasn't very effective on the road noise.

Next, a couple of layers of damping material under the rear seat, and that helped a bit too, with the sum of these things making the back seat area much quieter.

However, much of the road-roar was still getting in the car, apparently through the forward floor pan. It would appear that the floor pan in front of the seats is fairly flimsy, and not supported except at the edges, which permits a lot of resonance and sound transmission. I tried foaming the under-floor box-section beams, and this helped a little, but not as much as I had hoped.

I've been reluctant to pull the seats and carpets to dynamat the floor, as I have a bad back and don't want to pay someone to do it for me, so today I tried a different approach, which worked quite well.

The idea was simply to damp the floor pan in front of the seats, with something other than dynamat on the sheet metal. This requires some mass to keep things from vibrating and resonating. My approach was to place a couple of deadened steel plates on the factory floor-fuzz underneath my carpet mats. This damps the floor nicely, and keeps much sound from going up through the floor mats. The net is a reduction of maybe half of the road-roar - I can now proceed without turning up the stereo when I hit a section of these older noisy highways. Further, the foot-massage at traffic lights is now gone entirely, which demonstrates that low-frequency vibrations (like road-roar) are being quenched before they get inside.

To make these metal plates, I got a couple of pieces of 1/16" steel diamond-plate at the local Ace hardware, and cut them down to fit the floor on either side, roughly 16"x20" (the two sides are different shapes and sizes). I covered the flat side of the steel with a layer of generic dynamat to keep the plate from 'ringing', and sprayed the diamond side to keep the rust-demons away. I placed them on the floor, put the carpet mats on top of them, and Presto - much less road-roar now gets in, and I can hear the stereo reasonably well at 70.

The steel panels added about 18 lbs to the car, but worked better than anything else I've tried at killing the road noise, so I view this as a good tradeoff. Unlike dynamat on the floorpan, they are also instantly removable if I ever decide to do anything where weight matters, like a track day...

Still to come - dynamat inside the doors and boot lid...

 

they are pretty quiet on my MC

 

I tried those. Yes, they are quiet but I love my studded Nokian Hakka 2s in spite of their noise. I'll take traction over quiet anyday, thank you very much.

 

Oldrick, do you have a digital camera? Would like to see some pictures

 

Dang! Should have just bought a Lexus. Seems like quite a waste of time and money to me. I guess you'll never get a cycle. Talk about noise.

 

I'm running on 15x7 SSR Comps with 205x55 Michelin PE2. They shouldn't be particularly noisy tires.

I've had a couple of bikes and some loud cars. The issue for me is that noise becomes tiresome and makes conversation difficult. I also find that I can drive better if there is less of the constant road noise that masks the audible signals you get from the important parts.

Other than mechanical noises that let you know it's got an engine, I can't think of any reason why a high-end small car should be loud inside.

 

Whats the problem with wanting something that handles great and is dead quiet???

Anyway, it'll be great if you can post pictures OldRick, would like to see what size you cut your steel plates to.

 

Avon M500 tires are the quietest tires I’ve ever experienced and go a long way to reduce road noise. The road noise transformation is dramatic due to the tires alone.

When you deaden the door skins also treat the door trim panels. Those plastic pieces vibrate and the recessed dish area behind the armrest will act like a drumhead. Another resonating area is the panel in front of the gas tanks; it’s surprisingly thin.

OldRick, check out the first two pages of my gallery for a couple of places you haven’t addressed yet.

 

Good tips Huevo - Thanks.

As to size, check your car first, but mine was 20"x16-1/2" for the driver and an inch longer for the passenger.

I probably could have made the passenger side a bit wider than I did cause it's an irregular shape, but I didn't want to have to cut the shape. I should have made a cardboard template of the shape of the flat part of the floor.

The driver side plate fits up snug against the base of the gas pedal.

 

As to pix. there's nothing much to show - just a flat rectangle of metal - black on the diamond side (paint) and aluminum on the other side (sound damping sheet). I did cut each corner about 1/2" at a 45-degree angle, to reduce the chances of poking a hole in the fuzz-carpet if the plate were to slide around at all.

I placed them diamond-side down, so the diamonds could help resist sliding, and my floor mats have rubber undersides so they don't skid on the smooth side of the plates. So far no problem with floor mats out of place.

 

Great job Oldrick. I like the idea of having my MCS quite in silence. I'll take some advise.

 

Guys... it’s a mini cooper! Is not supposed to be quiet!!!!!!
Hello! It’s got a small chassi, sport tuned suspension, no sound isolating, and performance tires among other things!

If you want good handling and a quiet ride buy a 750iL or something like that!

Now if you absolutely need to have your mini make less noise... then I got a few tips....

- buy softer strut and springs
- buy high profile tires like a 195/65
- dynomat your car (take everything out of the inside and dynomat all of it)
- make sure you have a cooper not and 'S' kind of hard to keep and SC quiet)
- Take out you radio (no music)
- And last do not I repeat do not use you A/C (the A/C on the mini is as loud as it gets…)
I think that should do it…
oh, yes you now have a small minivan...

 

He said he is 70 if he wants his car quiet he can have it quiet, he has been around long enough to earn it

 

I fully soundproofed my Miata last summer using viscoelastic polymer paint from SecondSkin and 1/8 closed cell foam.

I painted 5-6 layers of that paint (about 3 mm thick) in the trunk, under the carpet and back shelf, over transmission tunnel. I painted outer door skins, then sealed all the outer skin openings and put 2mm on the inner skin. Than I cut the foam and put in under the carpet and in the doors.

After test drive I was surprised at the amount of rattles I couldn't hear before, like loose wires, trunk opening springs(torsion beams), heatshields etc. It took some time to locate and fix the now obvious rattles.


It took me 2 gallons of paint to do the whole car and when dried it is less than 15 lb. I don't think Dynamat is that light. Foam weights next to nothing.

The materials cost me around $250 and I spent over 100 hours taking the interior apart, painting and putting it back together.

Most of it is applicable to MINI. I would guess that the doors and hutch soundproofing will give the best results.

Leon

 

I understand his point of view, the problem is that the built of the mini does not offer a quiet ride... it is too small to be quiet.

 

cool

 

I have an MCS with viscoelastic sound deadening material strategically placed over a two-year period. It’s not over every square inch and yet it is highly effective at both reducing resonation and providing a barrier against outside noise. I never once put it somewhere and experienced no effect. It is simply untrue that the MINI cannot attain quieter status using “Dynamat” style material in a limited application. My supercharger has the pressure relief ports closed off, it’s overdriven, and my belt is a whiner, I’ve got lowering springs and fifty aspect ratio tires, but that doesn’t offer any obstacle against improving my driving experience via viscoelastic sound deadening material.

My MINI is much smaller than my former ¾ ton 61 GMC long bed pick-up and much smaller than my girlfriend’s 94 F150, but it is much quieter.

 

Can you link or show a picture of this material you're talking about? I'm very interested in trying them out

 

Pictures of the application can be seen in my gallery and the products (Brown Bread, Extreme, Ultimate) were purchased from B-Quiet/Stereo Types in Canada http://www.b-quiet.com/ and Dynamat was sourced locally.

Xtremepsionic, I like the idea of an enclosure within the rear speaker compartment and I am planning something less involved than the thorough arrangement you created.

 

k-huevo,

I checked out your gallery. You've done a fantastic job with your sound dampening material! I did a full Dynamat job on the interior of my Miata years ago which helped tremendously. One of the surprises on the Miata was discovering that a couple of 10" x 10" sheets of thin magnetic material placed on the underside of the trunk lid reduced the interior noise by 2 to 3 dB at 40 mph. Standing wave resonance, perhaps? I'd love to check out your MINI, maybe at the next Hill Country Rendezvous?

Actually, I found this thread by searching for "quietest tires". I currently have 205/45-16 Toyo T1-S tires on my MINI and it is the noisiest tire I've ever experienced. The Volks also fit on my Miata, so I was able to verify that the Toyos were much noisier than the 195/50-15 Yokohama ES100s on my Miata. Oddly enough, Factory Lotus Elise wheels with Yokohama A048 "track ready" tires also fit on the MINI. (see attachment) These were also much quieter than the Toyos.

I saw your recommendation of the Avon M-500 tires. What other tires have you compared them with? I reeeeeaaaally want to get rid of the current four wheel drive mud tire sound of the Toyos, and I'm probably going with the Yoko A048s unless the Avons or some other tire proves to be quieter.

Just as a side note to those that think the MINI doesn't need to be quieter, my Elise with no sound deadening, no carpeting, and with the optional "sport" suspension, is still quieter than my MINI on most road surfaces.

Thanks for your help!
John

 

The tread blocks on those A048s are huge so the Avons are defiantly going to be quieter. The ES100 tires I had before began to get noisy around the 8,000 mile mark but the Avon tires are still quiet after 10,000 plus.

DiD has a good idea about placing sound deadening behind the wheel housing cover on the outside of the cabin. I had the housing cover out looking at that area today thinking that it might take something a little more than viscoelastic material and your mention of the magnetic sheets sounds like an option although it would have to be malleable to fit the contours. I assume this stuff is like company logos and racing numbers.

 

damn, thats loud

 

Yes, the magnetic sheets were actually the logos from our local Miata club. I like DiD's idea about coating the back of the wheel housing. That's definitely where most of the noise is coming from. I've also wondered if some of the road noise is being transfered to the body from the rigid mounting at the top of the front struts. Maybe a layer of Dynamat between the strut top and the mount?

BTW, the more I look at your gallery, the more intrigued I am about your MINI. I need to find your posts on the engine work you're doing.

John