Jojohoy

I'm certin I'm not the first to do this simple yet very effective upgrade, but I felt with hot weather coming on, this could prove useful to a few of us out there. Even if you don't have working A/C, this upgrade enhances you chances of staying cooler. There are many different types of sound proofing materials out there and most are really expensive. I use the stuff from HomeDepot that is intended for furnace ducting but works great here too.

Yes, I know I didn't cover every inch of the floor, used scrapes for that area. The roof is where I was trying to concentrate my efforts for better heat reduction. This stuff is foil backed and it will cut the finger coz the edges are sharp. If you really want to go whole hog, use foil tape to seal the seams and you wiall hve done all you can do.

I did my entire floor and roof on my 1998 XJ for less than $65.00. The reduction in road noise and typical resontating rattles drop dramatically. I like the effect it has on keeping the humans inside cool in the heat of the summer. A/C works so much better with the roof insulated.

I hope this helps somebody out there.

Thx!

investinwaffles

I did my floors with Frost King, and doors with Noico sound deadening. Honestly, the floor made the biggest difference in noise, and an added benefit of a huge decrease in cabin temps.
​​​​​​
Need to do the roof when I re-do my headliner.
The one thing about Frost King is the adhesive sucks compared to real sound deadening. I wouldn't use it in vertical surfaces but the roof gets sandwiched with the headliner so it'll work just fine

steed76

Interesting! I live in south Carolina and the heat gets unbearable here. This is the first year having my xj here, and my headliner needs done anyhow. I wonder how theasy adhesive would hold up to 100+ summer temps? Please keep this updated, as I could have the carpet and headliner out in 2 hours. Anyone else have anything to add?

Ralph77

What did you think off the Noico? What thickness did you use? 50 mil or 80 mil? I am thinking of cheaping out and buying that instead of Dynamat. While I don't really care about the noise because of upcoming projects I have to open things up. Have to chase down a leak in my rear hatch so I have to remove the plastic trim and see where it is. I have to remove my door panels to install Infinity Tweeters I picked up. I am putting in an overhead console so the headliner needs to come out. Putting in removable headrest leather seats, power on the driver's side, so some of the carpet has to get pulled up to run the wiring.

My current thinking at the moment is use the Noico, achieve 25% coverage, in those areas. Inside the outer and inside the inner door panels, inside the outer and inside the inner hatch panels, the roof, and floor. Thinking of POR 15'ing my front floor pans first. Was thinking of going with the 50 mil but it is currently unavailable through Amazon. Might be when I am ready to do the job. Then I was going to use a closed cell foam. Thinking this for the roof:


Using self adhesive stuff there because I would never have to remove it to get at anything. Now for the floor, under the carpet, doors and hatch, under the plastic trim and door panels, I was thinking of using this:

https://www.zoro.com/e-james-sponge-...5p/i/G4337426/

Under the carpet it would just be laid in there. Behind the door and hatch panels I was thinking I would secure it with some Velcro. Thinking being if I ever have to go in there I could just pull it off, do what I need to do, and reattach it. Of course cut the appropriate holes and slits for wiring, door lock rods, etc.

Anybody see anything wrong with this plan of attack?

investinwaffles

Same, I bought it and just kept it in the garage till I had the door panels off. Next time I have to fix the rear hatch lever (seems to get stuck once a year or so) I am going to do the rear hatch with some.

You honestly dont need 100% coverage to make a big difference in NVH (noise/vibration). For heat, you will definitely want full coverage though.

I used about 70% of their 36sq ft to do the front two doors at about 75% coverage, and the rear cubby area where I installed a subwoofer at 100% coverage basically. I still have 2 sheets left, and will probably put 1 in the hatch and split the last sheet between the two back doors, or buy some more because its really not that expensive.

Dynamat, and Damplifier are super expensive, not worth it on a cheaper vehicle. Noico is cheaper than FatMat and does just as good of a job, considering how noisy the XJ is inherently. You will only gain a very marginal improvement over the cheapest sound deadening, with significant increases in price.
Really, all that matters is the adhesive being good enough for vertical surfaces like in the door. I used brake cleaner and isopropyl to clean as best as I could and made sure to press down on every inch that I could. Seems to be holding fine, but have not gotten into the hot weather yet.

The Frost King did really well under the carpets too. I feel like under carpet or headliner, the adhesive becomes less important and I think FrostKing has better heat rejection properties. My floor would seriously get to 130+*F above the carpet by the trans tunnel. I did 2 layers there, and where the exhaust runs for good measure. I pushed it up as far as I could on the firewall in the cab as well. Made a huge difference, too bad I didn't have any when I did my heater core or I could have done the entire firewall properly

RegularGuy

I wonder exactly what the "HGDS Deluxe Insulation Group" actually is... was it just a Phase II XJ thing or was it always an option?

I ask because my current XJ has it listed, and i wasn't sure what it was. now the other day i realized it has extra weather stripping on the leading edges of the doors.

maybe thats another idea to cut down on some of the wind noise?

It also hadnt occurred to me that insulating the floor would cut back on heat. I assume due to the engine heat and exhaust?

tech

Has anybody tried using 1/4" cork for noise and temp. I used cork many years ago in other cars I'v built and it works great , it did not have the foil backed and I think it would work better for noise and old ice coolers were made with cork to insulate . so has anybody tried it in the roof of a XJ ?

tech

I would like to know what other people used ? I would hate to add a hundred pounds of insulation .

investinwaffles

I dont think cork would work particularly well unless it was pretty thick, maybe just against radiant heat but frost-king is probably better because of the foil layer and how it is very closed cell foam.

I would go with Frost King, its not that heavy. Probably 20-30 lbs for the roof alone

EDIT:
Also, I had to take the rear drivers side door panel off to change out a window after a thief broke into my car a few weeks ago. I did about 5% coverage on the outer skin and it made a considerable difference. Not as big of a difference as 75% that I did on the front two doors, but honestly if you are just looking for a little dampening, 10% coverage on the doors would be the way to go.
When I tap my fingers on an undampened panel, it makes a ringing noise almost. With the 5% coverage, no more ringing harmonics, and has a thud when closing the door instead of a clang.

Very happy with the Noico 80mil stuff

_StationWagon_

"Thud ...
Clang ..."

All this tech talk is way over my head! Can you please stop with the tech terminology and write so we lay people can understand?

investinwaffles

Hah, here is a good test.

Drum your fingertips on the door panel. You should be able to hear the door resonate, especially the outer skins (they are thin sheetmetal).

Now, hold your other hand on the same panel and repeat, giving a simulation of what a "dampened" panel sounds like. Should eliminate all of the resonance

LiamLikeNeeson

What if you just took a few layers of foil and taped it to the side of the cork board that would be against the roof? Reflective (there's a reason why the instructions of frozen burritos calls for them to be wrapped in foil when in the oven) because of the foil, the cork would be nice and thick, and honesty, cork would be a pretty cool headliner material. I also saw someone write a thread on using straight up housing insulation (asbestos free) in between the headliner and roof and it was pretty good at reducing wind noise. Or a heat resistant blanket, like those thick ones, in between the headliner and roof? I don't have a headliner since it broke on removal so I might try the cork board if I don't find a headliner board in good condition (although I'll take a look around when I'm at the junkyard looking for a replacements trans).

_StationWagon_

ummm ... I understood perfectly. I wasn't being serious ...