I found this gem of a DIY on my350z.com… lol, GHETT-O
DIY – Rear compartment sound proofing
Sorry if this has been posted before…searched and didn’t see anything on this.
While removing my spare tire to insure proper inflation I decided to sound proof the compartment where the spare resides.
I used cotton bath towels mostly (along with some old t-shirts) and completely covered and filled in under and over the spare tire compartment. I believe that this hollow space directly above the muffler acts like a drum in some respects and makes a much louder booming sound while driving that is necessary.
I think the more large towels you can cram in there the better the sound proofing. Also once its covered by the lid and carpet you cant see a thing but you will hear a difference. Especially on rougher pavement. A side bonus to all this toweling is that if you ever need to actually change out a flat you have towels to kneel on and clean your hands afterward.
1. Remove spare and re-inflate to proper PSI.
2. Cover floor of compartment with towels.
3. Re-install spare and insure lock down fastener tight.
4. Cover spare and fill in excess space with further towels. The more the better!!! PACK IN TIGHTLY as possible.
5. Install spare tire compartment lid and carpets.I think Black towels would even look good if you could find some.
Time: 10 mins
Cost: Free if you use old t-shirts and ragsGood LuckΒ
I’m not making this up: Thread Link