Spike100

Note: This has been discussed before… numerous times… so you may want to disregard this if you have previously read the same stuff.

One thing I notice about the Z is the amount of outside and road noise the coupe model transmits to the car’s interior. If you drive a G35/37 coupe, it’s very quiet in comparison.

The Z coupe allows an excessive amount of noise into the car’s interior. I suppose that is because the rear wheels are inside the car’s interior in the Z’s coupe configuration. Of course some sound deadening would help this problem, but I suspect that many Z owners do not want the added weight.

Summer performance tires definitely add to the problem when a car has no or little sound deadening. I can say this because my winter wheel/tire setup (studless snow tires) is so quiet compared to my summer performance wheel/tire setup.

I did install sound deadening inside the doors, and that was necessary to avoid vibration from my Focal speakers which deliver a lot of bass. Without sound deadening, the doors vibrated and rattled. That went away with sound deadening, and it did make the car a lot more quiet (generally).

My question: Has anyone installed sound deadening in the rear cargo area (including over the wheel wells and under and around the rear section behind the driver’s and passenger seat), and gained a significant improvement in eliminating road noise (especially from the noise you get with summer performance tires coming through the rear wheel wells).

--Spike

PS: Please do not tell me to search. I’ve done this extensively, and the results are not conclusive. I see posts saying it's not worth doing all the way to saying it is mandatory.

gsxrsellout

iTrader: (1)

I did just sound deadening under the carped, the trim pieces and throughout the doors. I have a roadster model and I noticed a world of difference for reduced road noise. I don't have nearly as much road noise, wind noise, or other outside annoyances as I did before.

I would suspect that if you did it in the coupe the results would be even better than my roadster.

cheshirecat79

iTrader: (9)

I used Dynamat on the entire rear hatch upper and lower area. Stripped out all the material, spare tire, etc. Noticeable difference, I'm glad I did it. However, nothing I know of will solve tire noise once you start getting lower on tread. That's what we run into with wheel wells inside of the cabin.

Paul350Z

iTrader: (1)

I wrapped everything aft of the chair back with deadener and put two layers over both fore and aft wheel wells. Works pretty well and now I can't hear the tiniest pebbles knocking on the wheel wells.

TheOtherRob

iTrader: (14)

I finished up the top of my hatch, bottom around spare tire and behind the passenger seat in glove box floor and I noticed a small difference in exhaust noise, and more of a decrease in road noise. I haven't done the wheel wells from inside the car yet because its a pain to remove all that plastic crap. So Ill save doing those when I already have it apart for something. The increase in bass was awesome as well, sounds so much cleaner now and less outside vibration noises. I used dynamat extreme.

Dirty Dave

iTrader: (8)

Just finished up doing my whole car with edead80, closed cell foam and some open cell. It definately made a difference with road noise and rocks kicking up in the rear wheel wells. Once I get some time I would also like to try to further the wheel wells with some sound sludge I think its called. Pretty sure someone on here had good results with it, it can be sprayed or painted on the outside in the actual wheel well. Might be another option to also look into.

Spike100

Wow… some “big hitters” responding to the thread… Thanks guys!

It’s obvious from these replies that sound deadening in the coupe’s cargo space provides a benefit. I’m going to go ahead and do this. I think I will also do the “spray-on” sound deadening outside the car on the outer wall of the rear wheel wells (what Dirty Dave mentions).

The only downside I see is a little extra weight, but that’s not significant in my situation. The body shop I spoke with about the exterior spray-on soundproofing applied to the outside of the wheel well assures me that it won’t promote rust. In fact they claim it's a type of rust-proofing. I guess that I will find out firsthand.

Thanks again for advice and posting your experiences. I really appreciate the help.

--Spike

cheshirecat79

iTrader: (9)

Let us know your impressions after you get it completed. Good luck.

Spike100

Thanks for your reply and positive encouragement.

For sure… I will report back after doing this. My plan is installing sound deadening in the rear of my Z coupe, paying special attention to the wheel wells and the rear “floor.” I plan doing this sometime soon, AUG 2009.

I am also going with spray-on sound deadening inside the outer surface of rear wheel well.

I’m planning this in two stages (interior sound deadening first, followed by the spray-on) so that I can evaluate the advantages/benefits for both solutions. I’ll give a report on both efforts.

This won’t be “new news” since at least a few other members have already done this. My “news” will only be a fresh look at this solution (but. that’s not without merit by any means).

I’m going to use a professional installer for this so that the report is not affected by mistakes made by an amateur (that would be me).

--Spike

BTW: I would take this opportunity to thank you for your participation on my350z.com. I notice that you consistently provide useful help and advice for our members. I appreciate your good responses and your efforts.

And.. I don't want to short the other guys who replied on my thread (gsxrsellout, TheOtherRob, Paul350Z, and Dirty Dave).

Paul always gives the right and wise answer, and the other replies from other members are right on for my question. I received answers from the best guys here.

jZ08

I had Kingpin Audio do the fully monty on my Z when it had 500 miles on it. If you're ever down in the PDX give me a shout and I'll give you a ride. They've done this to a lot of Zs.

I had them do the firewall, floor boards, doors, rear area, and ceiling. The only thing I haven't done is the wheel wells; they report that it doesn't make any difference. It took them a day to do it.

I am extremely happy with the work they did. I hadn't worked with them before and handing over my Z with 500 miles on it and I was very apprehensive since I am picky. I would not hesitate to do it again or to recommend them to do it.

I just made a repeat visit to them and had them put in an HD Radio & iPod adapter. Flawless work again.

cheshirecat79

iTrader: (9)

I think you could tackle this yourself if you wanted to. There is quite a bit of information on the internet as far as how to apply the sound deadening material. Before you commit to hiring an installer, try doing some searches on youtube and google to see if you can find some info on application of the product. After all... money you save on labor can be used to buy more mods. Also, learning how to do something and then doing it yourself will give you the satisfaction of knowing you were able to pull it off.

I'm glad we were all able to help you out.

Diesel350

iTrader: (6)

IMO if you want to get rid of excessive noise just putting in sound deadener won't do the job. You need to add an effective barrier and absorber composite mat like Luxury Liner which would make a big difference in keeping out noise.

Spork

iTrader: (6)

I laid eDead v1 through the entire rear and middle area when I did my audio installs. I wasn't so much worried about heavy sound deadening as I was about getting rid of resonance and rattles. It worked wonders while reducing road noise by like 5%. Maybe it's just placebo effect and I never paid attention to road noise prior to laying it down.

Spike100

So... that would be adding a layer of dead-air space along with the sound deadening layer?

I get your point since that is what's done in multiple dwelling and industrial construction to provide decent sound-proofing between units.

--Spike

Dirty Dave

iTrader: (8)

Using edead80 then closed cell foam over that and open cell ( juke ) over that, I think I accomplished a similar solution. And was done at half the price. Luxury liner is very nice but very expensive.

Diesel350

iTrader: (6)

Yes adding a layer of open cell or closed cell foam on top of sound deadening would be the most effective in keeping out noise. Obviously if you are putting down a thick open cell foam you will only be able to put it down in the trunk and floor boards. A thin closed cell foam like Neoprene/Overkill/Ensolite would be most effective inside the doors on top of the sound deadening.

Diesel350

iTrader: (6)

The only problem I see with an open cell foam like Jute is that it has the possibility of absorbing water and getting moldy.

Luxury Liner Pro is definitely expensive but it is bonded to a water resistant closed cell foam to keep the water out. IMO I think it's worth it than to risk putting Jute in and then having to rip it out later.

Spike100

Thanks much Diesel… I’m going to follow your suggestions (they make a lot of sense, and I'm not cost-sensitive on this project since it won't be terribly expensive).

--Spike

adamtaylorpcb

iTrader: (7)

it can be, deadening your car should run you about 30-50% of your total audio upgrade budget to be done right



if it were me and money wasnt a thing i would do a layer of damplifier pro (2 layers in some places) followed by spectrum followed by luxury liner pro

jtabraham

iTrader: (46)

I did the my entire cargo area about a year ago. Pulled out all the panels, and coated everything with a thick coat of eDead v3 (used a gallon total). Over the eDead, I used 3/8" neoprene (doubled up in certain areas like on the wheel wells). With that much thickness, it was tough to get some of my panels back in.

Above the floor board and below my carpet, I used two layers of carpet pad. I could not find a single carpet store that had any jute in stock, so I used the multi-colored foam stuff that you get at home depot for area rugs.

Maybe it's just my imagination, but I think that helped more than anything else.