Sound damping and insulation on the hood
Posted: Wed Jul 31, 2013 10:07 pm
I finally got around to doing this. It's not as dramatic a change as the front and rear fenders (the worst offenders), but it's very noticeable. Pretty much killed all of the accessory drive noise (a/c compressor, etc.) and a lot of front end road noise, and mutes the engine a little bit. Definitely quieter overall.
Several ways to do this, but this time I wanted to copy something I'd seen before and use the stock plastic clips to hold a better hood liner in place. I used products from Second Skin, some aluminum tape and ten replacement hood clips from Nissan.
Started with damping using Damplifier from Second Skin:

I needed to leave the holes for the clips unobstructed and I didn't want to add more weight than I needed to, so I kind of quilted it in like this. Except for doors where I want them to be super-deadened for sound quality, I generally add just enough to damp away resonance in the panel. It doesn't take that much, particularly if you put it on the center of mass of the unbound panel area...which is usually just the center. Since this ends up getting covered I don't care that it looks all over the place either.
Next I used some left over scraps of "Motor Mat" to fill in the depressions between the ribs:

Second Skin doesn't sell this product anymore but Dynamat still makes one called Hoodliner I think. Before I've stuck a sheet of this across the hood and called it a day. It's a really good open celled foam with an aluminum barrier that absorbs high frequency sound well.
Last I used a sheet of Heat Wave Pro, which is something like fire retardant carpet jute with aluminum barriers on both sides:


I started by using the stock hood liner as a pattern for both the rough outline as well as the holes. I did final trimming in place and used aluminum tape to seal the edges to prevent water intrusion.
Looks a little better in person, and it works a little better than I expected. Particularly for that annoying A/C compressor noise I don't hear much of anymore
Several ways to do this, but this time I wanted to copy something I'd seen before and use the stock plastic clips to hold a better hood liner in place. I used products from Second Skin, some aluminum tape and ten replacement hood clips from Nissan.
Started with damping using Damplifier from Second Skin:

I needed to leave the holes for the clips unobstructed and I didn't want to add more weight than I needed to, so I kind of quilted it in like this. Except for doors where I want them to be super-deadened for sound quality, I generally add just enough to damp away resonance in the panel. It doesn't take that much, particularly if you put it on the center of mass of the unbound panel area...which is usually just the center. Since this ends up getting covered I don't care that it looks all over the place either.
Next I used some left over scraps of "Motor Mat" to fill in the depressions between the ribs:

Second Skin doesn't sell this product anymore but Dynamat still makes one called Hoodliner I think. Before I've stuck a sheet of this across the hood and called it a day. It's a really good open celled foam with an aluminum barrier that absorbs high frequency sound well.
Last I used a sheet of Heat Wave Pro, which is something like fire retardant carpet jute with aluminum barriers on both sides:


I started by using the stock hood liner as a pattern for both the rough outline as well as the holes. I did final trimming in place and used aluminum tape to seal the edges to prevent water intrusion.
Looks a little better in person, and it works a little better than I expected. Particularly for that annoying A/C compressor noise I don't hear much of anymore
