Sound deadening 40 series Questions (1 Viewer)

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first post! so I'm hoping I'm posting this in the right area as I didn't see anything else relating to this on other threads.
Wondering if you guys have any experience with sound deadening the floors of your 40s.

I was originally thinking killmat, but now I'm wondering about boat engine insolation so I don't have to stick anything to the tub, downside.... is it's a lot thicker, but I'm thinking it would provide better deadening? and I'm able to take it out whenever I don't want it. both options would go under mats so not a worry there.
thanks!
 
Would kill matt on the bottom of a floor mat actually help? Or does it need to be on the metal to effectively work. If there is a small effect, might be worth it to try and knock down whatever dB possible. I do not expect these to be super quiet, but not having to always wear headphones on super long trips would be nice.
 
Would kill matt on the bottom of a floor mat actually help? Or does it need to be on the metal to effectively work. If there is a small effect, might be worth it to try and knock down whatever dB possible. I do not expect these to be super quiet, but not having to always wear headphones on super long trips would be nice.
the kill mat would have to be applied to the metal to work witch is a downside as I couldn't remove it whenever I wanted to. not too big of an issue, I guess I would just prefer whichever option would give me better sound deadening.
 
I would really love something to lower a bit the dB that is not glued to the steel so I can remove it if wet or not needed. I saw CCOT is selling something but not sure if it works.

Actually my truck came from the 70's with a rubber mat topper cut to the shape made of doormat material. It's a bit weird but it brings a bit of insulation (I'd say more heat insulation than sound) if you can accept to lose the factory floor look.
 
I would choose the boat insulation. It will insulate as well as anything in a 40. They are loud and almost impossible to make much quieter but that will work as well as anything and isn’t permanent. You need to be able to dry it and clean it out.
 
Trying to sound deaden a FJ40 is like trying to insulate a beer can. Unless you undercoat the entire underside and use sound deadening mats on the floor, fill the doors with something and coat the inside back fender wells you are just peeing in the wind. Oh I forgot the snare drum top... I suggest you put the money in your fix it fund for oil leaks and stuff that goes south. Heck, above about 40 mph I just turn the music off and listen to the gear whine and enjoy the rocks being thrown up against the underside of the back fenders. Below that speed I've got a pretty decent sound system and can talk to the wife. Just remember the saying about lipstick on a pig!
 
stuff i have in mine is 1/2" thick rubber mat material cut to fit under the floor mat in the foot wells. over the tranny hump i used closed cell foam because it is easier to shape. cut and duct tape together as needed. covered up with the factory floor mat anyways. more rubber mat on the rear floor area. would benefit from something on the firewall I think. its still pretty loud at highway speed but not uncomfortably so. but do need to speak up somewhat to have a conversation.
 
I would choose the boat insulation. It will insulate as well as anything in a 40. They are loud and almost impossible to make much quieter but that will work as well as anything and isn’t permanent. You need to be able to dry it and clean it out.
That’s kinda the direction I’m headed I think the thinkness makes it a better sound deadener as well as i agree with Geezer Cruzzer it is a bit of lipstick on a pig and I love the gear wine but at some points I’d like a bit of sound deadening and it sort of is the last “issue to fix” on my build
 
All good suggestions above and many more if you search the site. I started small and then went extreme - carpets help, paste down sound deadening helps a bit more, taking out the trans tunnel and sound deadening (I did to the bottom on mine) & adding material to the firewall (inside) ~ all make minor improvements. This also helps with noise, smells (engine & exhaust) from entering the cab. Then of course you can try rebuilding the noisy transfer case & chase down all the rattling parts (I periodically work the complete truck with sockets and screw drivers). In the end, the noise & comfort level will be marginally better. But, without A/c the windows are always down and there is road noise to add to the equation. Oh, and straight six isn’t exactly quite. Good luck with the noise abatement project.
 
All good suggestions above and many more if you search the site. I started small and then went extreme - carpets help, paste down sound deadening helps a bit more, taking out the trans tunnel and sound deadening (I did to the bottom on mine) & adding material to the firewall (inside) ~ all make minor improvements. This also helps with noise, smells (engine & exhaust) from entering the cab. Then of course you can try rebuilding the noisy transfer case & chase down all the rattling parts (I periodically work the complete truck with sockets and screw drivers). In the end, the noise & comfort level will be marginally better. But, without A/c the windows are always down and there is road noise to add to the equation. Oh, and straight six isn’t exactly quite. Good luck with the noise abatement project.
4cyl diesel... not quite but sure sounds good!
 
TLCnoise.jpg


But really, mine's not as bad as it could be.
R2.8: quiet
NV4500+one piece TC: Not quiet
Carpet inside on the floor: quiet
20 year old mudders bad, new BFG KO2s way better
Trying to cruise faster than 65mph: I don't

Sound comes in through the firewall so I always have the windows open so it can get out before it gets loud
 
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The sound is going to get into the cab... the PO of mine had a good stereo system, with a sub woofer behind the seats. Overhead he had install egg crate foam on the inside of the roof. Maybe it was acting like a sponge and captured some of the noise and music. Also helped insulate the top from the sun.
 
3/4” Dynapad comes with and adhesive back and I just stuck it to some rubber mats. I didn’t want anything permanently stuck to the floors to facilitate rust.
My top and doors are off 90% of the time. My main concern was keeping the heat from my catalytic converter off my feet. Found and OEM heat shield helped also
 
Folly........buy a Lexus grocery getter if you want quiet.
 

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