How many of you have added insulation to your car?

[Xist]

I thought that I had read discussions here. Do I want sound or heat insulation.

Yes?

I have seen a number of posts in different places about how much quieter [sound] insulation can make a car and how much they enjoy it. When I took my Accord to different body shops one suggested dropping the headliner and pushing out the dents.

Presumably with a mallet. I think that I prefer the headliner when I use my fist, but I still would not recommend that.

[types with one hand in an ice bucket]

I watched a video and it looked like I could drop the head liner in about five minutes and it looks pretty simple to install sound deadener on the ceiling. Here is the stuff that Shouty recommends: https://www.amazon.com/gp/product/B0...49e96b9b988901

Thirty-six square feet for $66 and I can finally cut down on all of that road noise at 55 MPH!

So, have any of you insulated cars? Do you prefer thermal insulation?

[oil pan 4]

Thermal mostly to the air conditioner lines.
Then added some sound deadening insulation to my diesel suburban a long time ago. Even then I used the sound deadening padding from a junk yard suburban. Cost was negligible.

[Frank Lee]

Just engine blankets.

[nemo]

Just turn up the radio, save $66. I would think the big source of heat would be the windows.

[Xist]

AC lines make sense, although I do not remember hearing about anyone doing that before. Was there any way to quantify the difference it made? Was your Suburban measurably quieter afterward?

That 3m window film would help, but I am much less concerned in this part of Arizona.

Of course, from what I have read, sound and thermal insulation are drastically different; insulation designed for one purpose does little to help the other.

[oil pan 4]

It didn't help the suburban much.
But covering the A/C lines with insulation always helps especially at low speeds, stop and go traffic, when stopped, ect.

[Vman455]

Originally Posted by nemo

I would think the big source of heat would be the windows.

This^^^. One reason many cars now come with a sound-absorbent layer in the windshield laminate, and many luxury cars with laminate side windows.

Xist, panel dampers like you linked to do one thing--lower the resonant frequency of panels to which they are attached (by turning some of the energy of vibration into heat). It doesn't take much of it to dampen a sheet metal panel like a door.

If you hang around car audio forums, you'll find lots of people using mass-loaded vinyl, a heavy material that absorbs sound energy. I've never seen any scientifically-rigorous test on the effectiveness of this for noise reduction in cars.

Of course, MLV is very heavy and expensive, so OEMs don't use it to sound insulate their cars. If you look at notoriously quiet cars like the Lexus LS and other luxury cars, you can start to pick out trends, like:

-Triple door seals. Most cars have an inner and outer door seal; lots of luxury cars and SUVs have a third seal close to the door edges.


2018 Toyota Prius door edge seal


2019 Jaguar XJL door edge seal


2019 Lexus LS500 lower door seal


2019 Lincoln Continental lower door seal


2019 Ford Edge rear door seal

-Noise-reducing wheels. The current Lexus LS has a resonating chamber in three of its available wheel designs to reduce noise.



-Sound-absorbent pads in the cabin. The Gen 4 Prius uses an unbroken layer of urethane foam under the carpet for noise reduction.



-Covers for access holes on inner door panels.

-Strategic placement of sound-absorbent materials.


2012 Lexus LS600h

If you're really serious about reducing noise, I recommend the second chapter of Theory and Applications of Aerodynamics for Ground Vehicles, "Noise and Vehicle Soiling" (T. Yomi Obidi, 2014), pp. 35-50.

[aerohead]

Accoustically insulated a friends Ford pickup around 1969.What a difference!
I thermally insulated my 1970 VW Transporter in 1976.Those air-cooled engine-based heating systems are so pitiful,I did everything I could to keep heat inside the beast.I was able to survive New Mexico snow-skiing trips and the Rocky Mountains all the way up and down,from Colorado to Banff,and Waterton International Peace Park,Alberta Province,Canada.