Sound Deadening Write-up
 

I finally decided to tackle the sound deadening project I have been wanting to do for a while now. I have had this goal in mind of making my 4Runner as capable off-road as possible while still being comfortable for me and any passengers. I imagine the comfort and luxury of a Range Rover with the capability and reliability of a 3rd gen 4Runner. Of course there are many things that will keep a 3rd gen from being a true “luxury” vehicle but it is good to have a goal.

My measure for success with this project was first, to reduce as much of the mud tire noise as possible and second, be able to cruise at highway speeds and not have to either crank the stereo to hear it or yell at my passengers to have a conversation. For me, interior noise level is a huge factor in what makes a luxury vehicle.

I have never done anything like this before and have never worked with these materials before. If anyone is an expert, I am sure they will be able to see things that I did incorrectly. I used a combination of posts from other members here and various resources around the internet including Raam Audio’s How To Guide (How-To)

Before I get into the details I will start by expressing how much time and effort this took. I knew it would be a large undertaking but damn… I worked on this for a few weeks, mostly on the weekends. If you are down on patience this might not be the best project for you. I think I am right on the edge of being able to withstand the tediousness of this job.

After a decent amount of research I decided to use raamaudio products. Certainly not the cheapest option but (without any comparison) it seems like a great product. The peel and stick application was great. I ended up ordering both package #1 and #2. Probably overkill for someone who knows how to do this more efficiently. It seemed like I was struggling to use all the sound deadener and had to stretch the foam. I also decided to go all out and get a roll of MLV (mass loaded vinyl) as well off Amazon.

The order of application is:
1. BXT Sound deadener (this is your Dynamat, or similar). This stuff reduces the amount of resonance in panels but does not actually absorb sound. Its mainly for the lower frequency sounds. You don’t actually have to have 100% coverage here. 60% or so is sufficient.
2. Closed cell foam. This is goes over top the deadener and absorbs the higher frequency sounds. This is the majority of the sound absorption. Full coverage is ideal.
3. Mass loaded vinyl. This is an additional layer of sound absorption.

Out of the factory the 4Runner uses a combo of all three of these. I found small patches of sound deadener hear and there, lots of foam under the carpet, and some MLV in the front footwells and trunk area.

I started out with the driver door. In hindsight I might have started somewhere else. Getting the driver door correct is important as its closest to where you’re sitting. I decided early on that I wouldn’t not try to reuse the moisture barrier. The sound deadening material, when applied thoroughly, should take on this role

The metal behind the vapor barrier was pretty dirty so I cleaned the entire door with all-purpose cleaner followed with isopropyl alcohol

https://i.imgur.com/umP6Ab6l.jpg

The doors were by far the hardest because of all the details you need to work around. You need to watch out for the door lock rods, latches, etc. The first material I put down was the BXT on the inner door panel. You can’t see the patch thats right behind the speaker. Placing BXT and foam behind the speaker should enhance sound quality.

Ideally you would get 100% coverage inside the door with the foam. I saw some people essentially ball it up and stuff it into every corner they could. That may be effective but I went for a cleaner install and made sure I had full sheets applied everywhere I could. Regardless, make sure you allow the door to still operate and keep the drain holes open on the bottom.

https://i.imgur.com/b9oD22Hl.jpg

Once I had ~60% coverage with BXT and as close to 100% foam coverage as possible I started on the outside panel. I used the material to cover the large openings in the door. I carefully cut the plastic backing material so that behind each opening was not just a large flat sticky surface. The biggest downside to this method is serviceability. When (not if) a door component fails I will have to cut this away and reapply.

I kept anywhere from .5” to 1.0” clearance around each plastic clip that holds the door panel on. This was sufficient for most areas.

https://i.imgur.com/jBmoGFHl.jpg

Here is the door fully covered with BXT. I tried to get as many large pieces as possible but I couldn’t avoid small patches in a lot of the areas. It helped to use a Sharpie to mark out the cuts ahead of time.

You will notice i cut holes around all the bolts so that they would remain visible. Another mistake I made on the first door was not leaving enough room for the interior door handle. the back side sits very close to the metal so you need to leave a square cutout for the entire handle. I also had to go back and change how much room I left for the door latch rod.

https://i.imgur.com/XzO7DIll.jpg

Finally, here is the door with the final layer of foam. notice the cutout for the door handle. I dint have too much trouble fitting the panel back on. It is pretty forgiving. There were some foam blocks on the back side from the factory that I either had to remove or move to a different spot.

https://i.imgur.com/08bvx3ul.jpg

Here are some pictures from the other doors. The rears were the same process.

https://i.imgur.com/K2MyDwQl.jpg

This image shows how I used two big pieces of foam in the door that overlapped over the crash bar thats inside.

https://i.imgur.com/iub6WiXl.jpg

https://i.imgur.com/8SRpCwyl.jpg

I removed the rest of the interior and started on the rear cargo area.

https://i.imgur.com/AxKXxJ0l.jpg

Picture taking started to slow down as the days invested in the project increased…

Here is the cargo area with all three layers applied. This was the easiest and quickest area of the entire project. The cargo area and doors will have the greatest impact.

https://i.imgur.com/Ldb4wlXl.jpg

Since reducing tire noise was a big objective I focused on the rear wheel wells pretty heavily. You can see all three layers were applied. Again, I didn’t just stuff foam into the corners haphazardly but I tried to get 100% coverage within reason. The amount of space behind the panels is pretty forgiving here as well even with the larger storage bin on the later models. That being said, expect the panels to be at least somewhat more difficult to assemble.

https://i.imgur.com/Olp1uBAl.jpg

Here is the left rear wheel well. I tried to get material in-between this opening and the rear door as best as possible. The gas filler is in the way.

https://i.imgur.com/dfiAgazl.jpg

Another shot of the rear. I probably could have done more alone the B and C millers but It was getting very tedious at this point… I did add MLV on top of the wheel wells after this picture was taken.

https://i.imgur.com/b4ZD63il.jpg

This is the rear seatbelt area

https://i.imgur.com/R0uBhQ0l.jpg

I moved on to the rear floor next. I applied BXT and foam to most of the rear floor under the seats but did not put any MLV.

https://i.imgur.com/473an1Fl.jpg

As I mentioned, I feel like I had a lot of BXT to spare so I ended up with almost 100% coverage on the floor. Unnecessary maybe but I cant imagine its doing any harm. 100% on the foam as well.

https://i.imgur.com/ifkP2Ktl.jpg

Here are some shots of the front floor. I also focused on the trans tunnel. Be careful building too much material up in this area. It will make the center console difficult to reassemble. I has to remove most of the material from under the cup holders because it just wouldn’t go down far enough to clip in. I also tried to peel back the existing material on the firewall and place even more here. Just make sure you leave room for the pedals to function properly.

Driver side:

https://i.imgur.com/EEH8LdPl.jpg
Passenger side:

https://i.imgur.com/JQfBEHll.jpg

Lastly, I decided to place a little foam on the back side of some of the interior trim pieces. This is the outside driver/passenger foot well trim

https://i.imgur.com/91XaHJyl.jpg

B-Piller trim

https://i.imgur.com/k87V8lml.jpg

Lastly, I had a few squares of foam at the end so I put them under the shift boot.

All in this project was a pretty big pain. That being said I think it was worth the challenge. I think I eliminated most exterior noise coming into the cabin with the exception of wind noise and unfortunately a good amount of the tire noise. The wind noise is expected due to the inefficient shape of the truck. Cant change that or the fact that we have single pane windows. The tire noise is significantly reduced but mud tires really just make a shit ton of noise, especially as the wear increases. If I had highway tires or even All-Terrains I bet there would be hardly any noise. You can really tell the difference when listening to music or having a conversation. Just opening a window at a stop light makes you realize how much more sound is kept out. The truck also just feels even more solid than it already did. The deep thud of the doors closing to the reduced crashing over bumps (even with a lift and tires). I am putting this project into the “mostly successful” column. Thanks for reading.

Would you you think your efforts you poured into this were worthwhile?

It's a pitty you can't get rid of road noise. But loud tires are loud tires....I agree with you on that

My carpet is ripped out right now as I'm waiting for new carpet.....still up in air if I should do alittle bit of this or not.

Sent from my Pixel 2 XL using Tapatalk

I have done doors in many vehicles, only one did I ever tackle the whole thing. I will agree that it does make a difference but for the effort required to include cut up fingers and bruised finger tips from pressing haha....it takes a lot of dedication to get this done. Your work looks really good man. Has to be better than it was before.

Thanks for such detailed write-up. I will store it in memories, although I am not sure I will be able to find time/money to repeat that magnificent job you have done )

As a fellow sound deadening adventurer, I commend your effort. You went further that I did, I never removed the seats.

If you are still getting sound from the rear cargo area, apply a second layer of foam if you have any left. I did a total of 4 layers in the back: dyno mat, foam, dyno mat, foam. That's where the majority of my road noise was coming from.

Another tip I got from a fellow member is to replace your driver's side door seal. That's the rubberized foam barrier that goes around the frame. It also cuts back on road noise. After that the majority of your noise will be coming from the firewall and the windows themselves so there's not really anything else you can do.

If you're on the fence it might be worth it to just do the trunk floor. Probably the most band for your buck and its relatively easy to do.

I think it was worth it for me considering my goals with the truck but no doubt it was a pain

My hands were a wreck after this. So many cuts! I decided if I was going to do this I would just go all out.

Appreciate the compliments. It is no doubt better than before and I have had my wife and others confirm that.

No problem and thank you! Happy to try and answer any questions if you ever do go for it.

Thanks! I actually did replace both front seals with some that were used but in great shape. My originals were cracked along the bottom. That is a great point though.

I could see adding more layers in the rear especially since I have the TRD exhaust making extra noise. I would be concerned about the fit of the rear carpet. It was already getting pretty tall with the layers I've added so far.

I also did the entire truck including the doors. huge pain. I also did a lot of the internal plastic. rear door inside plastic cover made a big difference.

mine was 100% dynamat

if you still have some left and want a nice little bump, do the cup holders. it's amazing how much more solid dynamat can make thin plastic feel like it's 2x thicker.

agree you can't get rid of the wind noise because the windows are single pane. I also did the roof because I had the headliner down as well. it did help a bit.

I guess the reward is shutting the door with that solid feeling. in the end I'm glad I did it but not sure I would do it again.

Impressive work.

I'm also impressed with what toyota did with insulation stockwise, at least on the 01-02 limiteds except the front cup holders (get warm). I've rented several newer vehicles some of which were incredibly noisy and transmitted lots of road noise and of course they all have highway tires on.

For those who do want to insulate further, I've used this on quads, underhoods and here and there under rear seats to insulate from exhaust heat. It's peal and stick,measure, cut and stick, easy peasy.

Heat Shield Insulation Sound Deadener For Auto Vehicle Hood Trunk 90"x39"x3/8" | eBay

Luck and enjoy the Runner. :cowboy:

raKnizek,

Thanks for the efforts and write up w/pic's, great job!
I imagine when closing the drivers door it must feel better as I am
still amazed at how lite these doors are. I am running a set of Discover A/T
tires by Cooper, aggressive in winter and not to bad for noise, at least until
you hit concrete pavement on the highways.

Again, thanks for all your efforts on the write up!

LMS

Is it worth the effort to do the roof in your opinion?

did mine as well. minus the roof. what a pain, however I am happy with the result. again it feels more solid. it was more worth it for me because I got to really clean the carpet and seats really well. all the panels in the back were coated with dust. Vehicle feels and smells.. newer haha 285 k I'll take what I can get

Saving. This is my next project after I get my runner mechanically sound.