AkechiMotors

Reading threads about weight reduction, it's clear that the stock sound insulation is really, really heavy. My car's not a racer, but I'd like to lose excessive weight where I can. I can't drive it without some sort of insulation - it's just to loud. So I was looking into a sprayed insulation like Lizardskin. Has anyone used this or something similar (there are a couple brands)? If so: 1) does it work; 2) is it considerably lighter than the stock insulation? Searching other threads, it looks like the stock insulation weighs anywhere from 50 to 65 pounds, so if a sprayed insulation is around 1/3 of that, it would be doing (plus, if it works as advertised, it should be superior to a mat-type product).

FrenchToast

Have you tried removing the original insulation? Not easy. And remember the factory insulation is applied in ideal conditions. So if you do apply something else, I would recommend doing it in a booth where moisture is controlled.

Can't comment on if it weighs less.

AkechiMotors

Yeah, I would probably do the prep work myself, then take it to a bodyshop to have the insulation sprayed.

odonnell

Curious about spray on as well. I did a budget job on mine with mat material, not sure how much you are looking to spend but I used a few rolls of this stuff from Home Desperate:

http://www.homedepot.com/p/Frost-Kin...V516/100028603

It's very light, especially relative to the factory sound deadening. It's slightly less quiet, but not by much. It stick onto (clean and grease free) metal pretty well so it's something you can DIY without having a body shop do it. It's not going to give the same results as spray-on insulation or Dynamat, but I think for the price and easy weight saving it's great for someone who's not looking for an all-out solution.

SloMo228

I used a spray-on type soundproofing on my 944, although I rolled/brushed it on because I didn't want to deal with overspray and protecting the interior and all that. It certainly is much lighter than the factory stuff, and you can vary the thickness where you need more insulation.

As to sound reduction, I didn't get as much as I hoped, but I deliberately applied a very thin coat to test. I bought two gallons with the intent of applying only one at first to see if it was "good enough." It isn't, really, but I didn't apply the minimum recommended thickness either. Two gallons will be plenty to apply a thicker coat over the wheel wells and cargo area, which ought to bring noise levels down to an acceptable level. Two gallons weighs about 22 pounds or so, so it's still a net weight reduction over the stock stuff.

944crazy

I came across this being done in one of the local boy's build threads. Seems like quite a novel idea, and does away with the need for carpet too, so a lot of weight savings to be had. Looks great in a dark interior in my opinion.

Not sure if he is on rennlist and can chime in here.

http://porscheforum.com.au/topic/645...44-ls1/?page=3

AkechiMotors

Cool - what brand did you use? Would you say that your application provided less sound reduction, or just comparable to stock?

AkechiMotors

That's a great thread - it's good to see someone treating a 944 as it should be.

SloMo228

It was Spectrum from Second Skin. In the thickness I put on, it's definitely louder than stock, but quieter than bare metal. I applied approximately 1mm thickness all around and their recommended minimum is 2-3mm I believe. I will be going back to build up the thickness in the wheel wells, rear seat area, and cargo area, as that seems to be where the vast majority of the sound comes in.

Edit: My situation isn't a direct comparison to stock since I have solid rear torsion housing mounts which increase road noise a bit, and I have removed the rear seat, which increases road noise a lot!

AkechiMotors

I plan to remove the rear seat as well, though I want to build a shelf to take their place.

FrenchToast

The rear seat and deck aren't really insulated at all, so you could probably quiet the car down quite a bit by applying anything there.

BTW, FWIW, I wouldn't touch the stuff on the exterior of the car (underside), if you plan to keep it on the street. That stuff, IMO, is some of the best in the industry.

J1NX3D

I haven't heard it used in a while

http://www.924board.org/viewtopic.php?t=29920

SloMo228

Yeah, there is no insulation at all under the rear seat bottom, so removing it increases noise significantly since the seat foam itself is what provides the insulation. I will be doubling the thickness of my insulation coating in that area and around the rear wheel wells. The pockets behind the wheel wells are another big noise area too. The hollow space just amplifies the road noise.