Sound deadening the Cruiser

[Luke111]

I think Fatmat is the best bang for a buck....100sq ft of the 50 mil for $99.00 or 50 sq ft of the 80 mil rattle trap fatmat for $73.00. Lots of pictures and details in my build thread of how I sound deadened my 80.
I don't know much about the science of sound and NVH but I do know my 80 is really quiet and I think full coverage is the only way to go. If you have the funds. Based on the prices posted... that 3m product is not cheap..... 3 inches x 50 Ft for $43.00..
Lou

 

[SUMOTOY]

Any info from 3M on installation guildlines on silencer strips?

Seems like $42 a roll is the going price?

40 or so is a good discount price IME, retail somewhere around 70 IIRC. WRT installation, there really aren't instructions, but when I was first introduced to it 12 years ago by a body shop guy, it's center of a given panel 'first', diminishing rate of return doing the 'whole' panel. The bigger the panel, the better the rate of return (read: rear quarters). My usual method is to do a strip down the center lengthwise of the panel, then take half the distance between that center strip and the lengthwise edge of the panel. IIRC, on the PS rear quarter, it's a tight clearance at the storage bin to quarter.

When I did the tailgate a few months ago, I removed the carpet and cut the strips up and put them between the stampings, so that the carpet would sit flat again. I'll pic it tomorrow. I also took a couple a strips and went blind in thru the 3 tailgate access panels to get inside the double wall. Just closing the tailgate with a solid 'thud' instead of the typical 80 'clank', I knew the tailgate was a good place to go.

I spoke to a family friend Chrysler NVH engineer years ago, and he was not a big fan of dynomat at all. Educated me well on Density vs Barrier vs Absorption goals and targets. When I spoke to him recently regarding the rear resonator bracket differences removed vs installed, it was he that suggested the rubber isolator there. He also said on a heavy truck like the 80, solid pieces of steel bolted/welded to frames and brackets (+welded to exhausts) can do a lot for Mass/Absorption of rogue frequency generators. Haven't tried that yet, but have seen many brake setups with steel resonators hanging on them.

Don't forget to address those splash shields on the inner fenders as well. Less auxiliary noise coming into the engine bay, means less noise in the cabin as well.

HTH

Scott J
94 FZJ80 Supercharged - selectively 3M'd

 

[Ebag333]

The 3M strips are a good way to go, very similar to the OEM setup. Good bang for the buck.


What they do lack is the aluminum backing. The aluminum does two things, one is that it helps stiffen the mat (reduces vibrations), the other is that it reflects some of the sound back. The mass absorption does the majority of the work, so the aluminum isn't crucial...but it does help.


The solid pieces of steel are interesting, I'd completely forgotten but Toyota actually does that OEM from the factory. There is one attached to the end of the exhaust (on the last mount outside the frame right before it dumps). I'd completely forgotten about that one until I removed it on the truck.

I'm currently driving a rental (Chevy Equinox) and noticed that they had done something interesting. The voids in the panels are filled with what looks like a type of foam or mesh (almost like the stuff you see in water filters for aquariums). Fairly open, but makes me wonder what difference it'd make in an 80. It's most noticeable in the front fenders, I haven't torn apart the vehicle to see if it's present elsewhere.

Don't think it'd work in the doors (except maybe a thin layer), but you could fill the front and rear quarter panels with it.

 

[Walking Eagle]

3M silencer strips are Mass density deadening, not really meant for 'total' coverage ala dynomat, it's designed to change the resonant frequency of a panel (like what the 80 has stock in the doors and PS rear quarter panel. A 50 foot strip box is plenty, if well placed about the 80, and will have better bang for buck than dynomat IME.

Manufactures use it to downguage material and prevent a tin'ie sound. Take a car door, reduce the sheetmetal thickness by 30% to save 50 cents, then put one piece of the 3M stuff dead center in the door for 10 cents and when you shut the door the door panel doesn't vibrate in an anoying way - tin-ie - high freq.

 

[SUMOTOY]

3M Tailgate

Well I managed to get the tailgate carpet off without breaking any clips this time. Here's a pic of how I did the 3m silencer treatment, the carpet sits flat this way. I also removed those 3 covers and put a couple foot long strips on the inside of the outer tailgate wall.

... What they do lack is the aluminum backing. The aluminum does two things, one is that it helps stiffen the mat (reduces vibrations), the other is that it reflects some of the sound back. The mass absorption does the majority of the work, so the aluminum isn't crucial...but it does help.

At the thickness of the backing used on the 'aluminum' backed insulation, you would probably be better applying aluminum foil. Technically, mylar adds the barrier and the strength as primary missions, aluminum backing is really there to absorb and disperse heat (vibration = energy = heat = aluminum is a great heat sink). The 3M wax backing can be removed and any material you want applied to it. For the best NVH, the butyl between two pieces of the same material gives the highest rate of return for noise reduction. Not really practical, but certainly something thicker than a few mils is better bang 4 buck than paying for the aluminum backing, if you are really after true NVH. I did this with my 4R turbo using galvanized ducting from Home Depot.

Manufactures use it to downguage material and prevent a tin'ie sound. Take a car door, reduce the sheetmetal thickness by 30% to save 50 cents, then put one piece of the 3M stuff dead center in the door for 10 cents and when you shut the door the door panel doesn't vibrate in an anoying way - tin-ie - high freq.

NVH is all about resonance 'tuning', certainly metal cost savings vs sound perception-value is one of the side benefits of sound deadening. But this 'cost' savings deadening was around when the material was 60% thicker than the 80 door panel. It's also why the 80 came with LTX tires instead of KM2's. And why Toyota spent a lot of money putting the puny stock exhaust resonator where and how they did. The bottom line is the 80 owner can realize noticeable difference from minor improvements in sound deadening without using the over-rated 100% dynomat.

If I didn't have such good compression on that 80 engine I picked up from you, maybe I wouldn't have this problem.

Cheers

Scott J
94 FZJ80 Supercharged

 

[Walking Eagle]

There are a couple different things your going after for 'sound deadening'

One is panel rattles - the 3M stuff is good for that - and has been discussed, there is no point in covering a whole panel with it. It really is amazing was a 3" strip of it will do for ya. 3M did a sales demo for us, and I got to keep some of it for personal use.

Then there is reflected sound. You have a sound inside the truck and it bounces around inside - that's not something the 3 product in made for. Well, it's not something that 3M product is made for, I'm sure they have one that is, they seem to make everything.

There is also transfered sound. Sound that is outside (tires, exhaust, road noise) that transfers through the door, floor ect. Carpet is actually great at deadening these sounds.

There is a bunch of information out there if you look for it, and I'd take a look at if before I started throwing money at dynamat, fat mat, or any other product. Hate to spend alot of money on something that is going to deaden the wrong type/source of noise.

Funny thing about noise in a car is whatever you quite down is only going to make the next loudest thing an anoyance. Quite the engine with muffler and isolation mounts and you start hearing body panels, quite them down with some 3 m and dynamatt, and the wind starts making too much noise. Quiet it all down enough and the loudest most anoyoing sound in the car is the key's jingling - and that's really anoying....

 

[Walking Eagle]

NVH is all about resonance 'tuning', certainly metal cost savings vs sound perception-value is one of the side benefits of sound deadening. But this 'cost' savings deadening was around when the material was 60% thicker than the 80 door panel. It's also why the 80 came with LTX tires instead of KM2's. And why Toyota spent a lot of money putting the puny stock exhaust resonator where and how they did. The bottom line is the 80 owner can realize noticeable difference from minor improvements in sound deadening without using the over-rated 100% dynomat.

If I didn't have such good compression on that 80 engine I picked up from you, maybe I wouldn't have this problem.

Cheers

Scott J
94 FZJ80 Supercharged

You say side bennifit - I say that's what 3M reps are selling it as now

They also have stuff for sound absorbsion

Thinsulateâ„¢ Acoustic Insulation

not sure if the siliencer strips is the same as the damping foil

http://multimedia.3m.com/mws/mediaw...5xfXo8s6EVuQEcuZgVs6EVs6E666666--&fn=2552.pdf

that's the stuff I was lucky enough to get for free.

you drop that motor into your truck? I take it everything was o.k.?

 

[gtfour43]

Quiet it all down enough and the loudest most anoyoing sound in the car is the key's jingling - and that's really anoying....

This really annoyed me in my LS430. I would hold the keys with one hand while driving

Damn quiet car though.

 

[SUMOTOY]

You say side bennifit - I say that's what 3M reps are selling it as now

They also have stuff for sound absorbsion

Thinsulateâ„¢ Acoustic Insulation

not sure if the siliencer strips is the same as the damping foil

http://multimedia.3m.com/mws/mediaw...5xfXo8s6EVuQEcuZgVs6EVs6E666666--&fn=2552.pdf

that's the stuff I was lucky enough to get for free.

Well if they sell it that way, I attest to the fact it works well... IIRC the Dampening foil like 2552 is a 'set' polymer with an applied 3m adhesive, the Silencer strips 08585 is a non-set butyl rubber (like a sheet of sticky silicone) that doesn't have a separate adhesive layer. The sheet is it's own adhesive and dampener. And allows one to put a thicker top layer on it, like a 'real' sheet of aluminum panel, or I found the galvanized sheets of HVAC ducting works well as a top layer.

you drop that motor into your truck? I take it everything was o.k.?

Yup thanks, that motor is awesome. I did 3.5 days solo swap from drive to drive. Grabbed the big dog engine hoist from the shop and did it in my driveway over a nice weather long weekend...

Gotta say, a lot of stress when going up and over the TJM... Started right up with the plugs that were in it (just changed them a couple weeks ago), did a couple oil changes and back to work. Now 15k later, still burns no oil and runs like a clock. Majorly bummed time/hassle wouldn't permit the splicing of the firewall-chopped low mileage wiring harness vs my crispy version...

SJ

 

[Luke111]

Deaden 80 sound test

This is the video I posted in my build thread,

I posted this on FB ... as some friends were asking question about my truck so its not very technical...basically for the novice... but it speaks volumes for the products and the results.
I think all these products are good and they all work in keeping cars quiet.
As stated earlier the Dynamat and second skin Spectrum were left over from my FJ55 project... but I did purchase 100 sq ft of Rattle Trap FatMat 80 mil when they had a special ... to good to pass up


YouTube - ‪Sound test 1996 Land Cruiser vs 2010 Lexus RX 350‬‏


Lou

 

[Walking Eagle]

This is the video I posted in my build thread,

Lou

"pretty thuddy sound" - love it.

 

[jeffro109]

just a habit of mine when doing sound deadener (when you want it done the best/most, etc) on doors is to take large pieces and cover the entire face of the door, basically replacing the plastic moisture battier with the rubber/alum sheets. Adding the same stuff inside the door to the outer panel prior to sealing up the door face and maybe putting a second layer over any large openings in the door face before putting the door back together make a really really quite door.

Leaving openings with only a piece of plastic lets any sound go right through to the interior of the car, covering the openings with something having mass and and least a little structure helps kill the noise. Another layer covering of the closed cell foam really helps too, but it can be hard to squeeze in there sometimes.

 

[Kernal]

Will 1/8 inch of closed cell foam fit on the back side of the removable door panels, and will the panel then still pop back into place easily? Is 1/8 inch enough to block any additional sound after using some dampening material on the steel door panels? Which closed cell foam works best?

 

[Ebag333]

I don't think with 1/8" foam it'll snap back on. I coated the back of the cardboard with Second Skin Spectrum, partially to water proof it and partially to add mass to absorb sound. It fits tight, and that's a lot thinner than 1/8" (maybe couple MM).

 

[jeffro109]

I doubt it would fit back on, you need a reasonable cavity to fit the foam in, or to be able to just put it under the carpet, etc.

Any dense, closed cell foam is better than nothing, some of the companies out there make specific sound deadening ones.

I have used the stuff from eDead (elemental designs) with good success, and am awaiting a large order of the deadening rubber sheets I ordered on sale, but no foam as its just not in the budget this time.

 

[Walking Eagle]

over compressing the foam is just like overcompressing insulation - it looses it's effectiveness. If you compress it as far as it can compress, you've just made a direct path for the noise to be conducted.

 

[Somebodyelse5]

Anyone have a lead on the 3M silencer strips? Doesn't look like it's available anymore