Back when I posted the Five Dollar Five Minute Fuel Cutoff the whole "5 and 5" thing was supposed to be a series. Well, I'm finally getting around to episodes 2 and 3. Today, we are doing sound deadening.
The best option for sound-deadening is to lay a Mass-Loaded-vinyl barrier, and then add some dynamat-style sound absorbing rubber to panels in the doors, and possibly fill large cavities with spray-foam. But stripping the interior takes hours, and if you can get a fourth the improvement in a hundreth the time, that's a good start.
A significant portion of the noise in the car comes from the exhaust, so we're going to focus on the rear of the car. The first problem is that the spare-tire-well acts as a drum, so we need to add some sound deadening in there. Basically, in all the space not used by the tire, you want to add some sort of cloth. I used liquid-nails to attach under-carpet-padding to the entire floor, and built up layers in the remaining airspace. You can use foam (cheap and light) or whatever you have around the house. Carpet scraps and old blankets also work well.
![]()
Ugly picture showing my trunk. The orange crayonbox controls my modified taillights, and isn't part of this project.
The second part is a bit more interesting. We now want to cut down on the sound from the rear tires and related components, which we do by isolating the trunk from the cabin. The existing barrier - the parcel shelf - is doing a poor job, but we can improve it pretty easily with two simple supplies:
![]()
Supplies. I didn't count the cost of the spraypaint because everyone has a can lying around, right?
You'll need two cans of expanding foam (which go on sale a few times a year for about $2 apiece, hence the $5 in the title), some spray paint, and a knife or a saw to do a bit of sculpting. You want to spray a layer of foam across the bottom of your parcel tray. After, of course, removing it from the car, I started by filling in all the channels, then adding a few diagonals, and filling in the open triangles like I was coloring back in grade-school.
After letting the foam dry, test-fit the parcel shelf. You'll probably have to trim the foam around the sides so that it will seat properly. I also trimmed the foam on the rear lip so that I couldn't see it peaking out at me. A saw or a heated knife work best for this part. Finally, rattlecan the entire thing black to so it blends in. It should come out looking like this:
![]()
Ta-da!
And that's it! Now you can talk to passengers while doing 70 mph without shouting!
The best option for sound-deadening is to lay a Mass-Loaded-vinyl barrier, and then add some dynamat-style sound absorbing rubber to panels in the doors, and possibly fill large cavities with spray-foam. But stripping the interior takes hours, and if you can get a fourth the improvement in a hundreth the time, that's a good start.
A significant portion of the noise in the car comes from the exhaust, so we're going to focus on the rear of the car. The first problem is that the spare-tire-well acts as a drum, so we need to add some sound deadening in there. Basically, in all the space not used by the tire, you want to add some sort of cloth. I used liquid-nails to attach under-carpet-padding to the entire floor, and built up layers in the remaining airspace. You can use foam (cheap and light) or whatever you have around the house. Carpet scraps and old blankets also work well.
Ugly picture showing my trunk. The orange crayonbox controls my modified taillights, and isn't part of this project.
The second part is a bit more interesting. We now want to cut down on the sound from the rear tires and related components, which we do by isolating the trunk from the cabin. The existing barrier - the parcel shelf - is doing a poor job, but we can improve it pretty easily with two simple supplies:
Supplies. I didn't count the cost of the spraypaint because everyone has a can lying around, right?
You'll need two cans of expanding foam (which go on sale a few times a year for about $2 apiece, hence the $5 in the title), some spray paint, and a knife or a saw to do a bit of sculpting. You want to spray a layer of foam across the bottom of your parcel tray. After, of course, removing it from the car, I started by filling in all the channels, then adding a few diagonals, and filling in the open triangles like I was coloring back in grade-school.
After letting the foam dry, test-fit the parcel shelf. You'll probably have to trim the foam around the sides so that it will seat properly. I also trimmed the foam on the rear lip so that I couldn't see it peaking out at me. A saw or a heated knife work best for this part. Finally, rattlecan the entire thing black to so it blends in. It should come out looking like this:
Ta-da!
And that's it! Now you can talk to passengers while doing 70 mph without shouting!