Fill or Not.... Sound Deadening Question(trunk lid)

[arizona 10+ year member]

Here is a picture of my trunk lid...

So should I fill all of those little holes with something? And if so...what should I use? Expanding foam? Or should I just leave them empty and lay the mat on over them?

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[James Bang 5,000+ posts]

be careful if you use expanding foam, don't put too much, you can warp the outer part of your trunk lid.

 

[gotparts90 10+ year member]

i filled mine with foam it helped. It is a messy process and it helps to tape over most of the hole then fill. Wait untill it sets up nice pull the tape and lay the mat

 

[arizona 10+ year member]

So would not filling them really make a difference?

 

[Fusion_FREAK 10+ year member]

Personally, I wouldn't fill them.

But, you can use 3M Polyurethane Window Mold. It's in a caulking tube, and is a rubber. I'd get the 60 grade rubber, because it's a little soft, and won't warp the trunk lid when it sets up.

 

[FoxPro5 5,000+ posts]

It's not worth it. If wet expanding foam gets on anything, you'll have to wait till it's dry to get it off. It has to be the stickiest stuff on Earth. On a vertical surface like that, it's going to be a mess. Not to mention the rather unpredictability of it's expansion and potential worping.

Put your sound deadener on the actual outer trunk sheet metal (those triangle shaped open spaces) then tap it a few times and see if it did the trick. If not, go back and cover the cross beams.

 

[arizona 10+ year member]

Alright. I didn't do it on the last trunk I did....but I was only using 2 12" Type R's off 1k lol. These two DD2515's off about 2k are just raping this little Subaru though. I really have to do the roof. That bish flexes so much its ridiculous.