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Posted by: Philip W. Jul 23 2018, 10:57 AM

I have seen some options out there,
1. Stock
2. After market
a. AA pad
b. Rix914parts- modern material, light weight
c. dynamat
d. 914rubber pad.

3. -others??

Also in the cab, the rubber sound deadener( I assume this was only for sound or vibration, since it is rubber I doubt it did much for heat) - I pull this out it was stock and am trying to decide if I should put it back in again or do dynamat or something like this on the inside firewall before putting the backpad back in

Posted by: 914Sixer Jul 23 2018, 11:35 AM

Inside the cab rubber mat was just for noise that would have come through the large piece of metal. The later cars 73-up got the firewall protection that turn out to be a rust disaster. I am going with the light weight foil application in the engine bay and dynamat in the cab.

Posted by: dr914@autoatlanta.com Jul 23 2018, 11:42 AM

ours is dye cut is waterproof and made from dyna mat, which is so close to the original 74.5-76 look, that the concours judges would not know the difference. We also have the earlier style sold by Six

Posted by: Philip W. Jul 23 2018, 11:59 AM

so no rubber pad then in your scenario. I did not have rust in my firewall, or engine shelf or hell hole dispite it being an Ohio car initially that moved to California before coming to SC around 2000. My rust was under drivers seat due to leaking window and jack points and rear longs. The original engine compartment sound pad was still in place up to a couple years ago and was really in good condition. Its gone now so I feel like I should put something in its place. If the dynamat one that George has has the reflective backing I will probably go that direction .

Posted by: Mueller Jul 23 2018, 12:10 PM

Anyone try Lizard Skin?

https://www.summitracing.com/int/search/brand/lizardskin

Posted by: Mikey914 Jul 23 2018, 05:46 PM

Stock will hold water and is pretty heavy, however it is stock. We are making a new one with a water repellent material that is light weight and has a rubber skin that looks like the OEM and has sound deadening properties. I'll get some pics up tomorrow.
Mark

Posted by: Olympic 914 Jul 23 2018, 06:43 PM

Used the X mat from Eastwood. Kind of like dynamat.

Posted by: forrestkhaag Jul 23 2018, 07:33 PM

I like what I see but I am taking a different approach.
I am using a cut out firewall metal piece as a mold for a carbon fiber duplicate of the firewall. Then I will be applying dynamat or similar to the (removable) carbon back pad shell.

The reason for this approach is multi-fold: The backpad, when easily removed, allows us 6-people to access the fan, belt, pulley, crank sensor, etc thru the firewall hatch (a carbon fiber part offered as a kit by ....me...) and the second firewall, although light and movable, also provides sound deadening when in place. Further, and most important, it looks very cool. Once perfected in the shop, I owe the donor of the metal firewall template the second one-off from the mold / then maybe others if interested. Pictures to follow.

Posted by: bbrock Jul 23 2018, 07:58 PM

I'm leaning toward reusing my stock mat but spraying the back and edges with Flex-Seal to keep it from absorbing water. My hunch is that deteriorating seals are part of the rust equation with these mats, and just knowing it might be an issue makes it easy to keep an eye on and make adjustments before damage is done.

Posted by: Chris914n6 Jul 23 2018, 10:13 PM

For the engine bay you will want something made to absorb sound first, block heat second. Add a sound absorber to the bottom of the engine lid.

For the inside, start with the aluminum backed butyl rubber sound mat that will reduce sound transfer thru the sheet metal and block heat. You can put the stock rubber piece back in but it won't be as effective anymore. Add a sound absorber like the foam back pad or carpet. Also adding jute under the carpet will reduce sound reflections.

Lastly, significant engine noise bounces off the street to under the seats, so do extra back there.

PS. make sure the rear window is well sealed.

Posted by: mgp4591 Jul 23 2018, 10:35 PM

I've heard people having good results with Norco but I'm not sure if it's waterproof. I'm considering it for my interior...

Posted by: Mikey914 Jul 23 2018, 11:09 PM

Dynamat is perfect for the cockpit side of the firewall. I have it on my blue car. As for re using the old back pad, not a problem as long as you don't get it wet often, and if you do you can take it out and dry out. The flexseal would be a good idea on the top and sides for sure. The main problem I have with the old ones is that they are just really heavy (and tarp water too).

Posted by: saigon71 Jul 24 2018, 06:51 AM

I put a lot of miles on my teener, so I wanted the interior to be "relatively" quiet.

I went with Fat Mat on the interior side - slightly thicker than Dynamat and Xmat but same concept.

In the engine bay, I bought a 914Rubber replacement back pad years ago. Same thickness and fit as stock but won't hold water. Its holding up well and I am very happy with it.

I'd stay away from using the stock one. Even if you seal the edges, it will find a way to hold water.

Posted by: Racer Jul 24 2018, 07:38 AM

Personally, I have only removed padding.. never added any. Never could understand why. Motor just never seemed that loud to me.

Posted by: Philip W. Jul 25 2018, 08:36 AM

Anyone ever use the dynamat door kits? seems like while my doors are open and stripped this would be a good idea too,

and they have a 1/2" pad that is water proof that would be perfect for the engine compartment pad or heat in rear trunk under the carpet. Either the dynapad(for under carpet no adhesive) or dynaliner-

Posted by: Philip W. Jul 25 2018, 09:02 AM

George, is it what they call Dynapad or the Dynaliner on their website?(your firewall pad you are referring to)

Posted by: Mikey914 Jul 25 2018, 09:47 AM

Matt has the dynamat door liners and also did the area around the foot wells. The dyenamat will help to reflect the sound back from the speakers on the foil side. Or so I've been told.

Posted by: Philip W. Jul 25 2018, 09:58 AM

I am thinking about ordering that kit- the kit is for 4 door, so I thought about using it inside and behind the outer panel both. I don't think I am going to have time to knock this all out now, but I want to do the doors while they are open, that is why I also just got my door rebuild kit and door stay replacemnent from you !. Next will be the inside under carpet and backpad, but not really necessary to get the car running and on the road. We are in need of a trunk pad replacement and that is where I was looking at the dynapad non-stick option- it is specifically designed for trunk or floor where exhaust heat is transmitted. Maybe someone could use an original for a template and cut them, like you and George do for your firewall pad???

Posted by: Mikey914 Jul 25 2018, 11:25 AM

Easy to cut you a part, the only hesitation I would have is in the trunk especially towards the back they could trap water.

Posted by: Philip W. Jul 25 2018, 12:55 PM

not as much of a worry really, this car will not ever be left outside other than during a trip to okteenerfest. Garage storage only- but if in a pinch it has to be outside, I have 2 covers - besides that, I have all new 914rubber.com seals so should be air and water tight, right??

Posted by: partwerks Dec 21 2019, 09:08 PM

I'm looking into it, and if it can be painted.
The guy that is going to do my media blasting does the truck liners,
https://linex.com/us/line-x-of-grand-island-F1153
and is wanting to expand to doing the lizard skin.

I would at least like to do the firewall.

https://www.hotrodders.com/forum/alternative-lizard-skin-103610.html

Posted by: Krieger Dec 21 2019, 11:44 PM

I used an extra, stock interior sound pad. I then trimmed it to fit on the engine side and glued it in place with 3m spray.

Posted by: Garland Dec 22 2019, 12:44 AM

Dr. Phil,
Check out my build link http://www.914world.com/bbs2/index.php?showtopic=265772&st=120# I state all the details, I like both of these materials. I used the EZ-Cool only in the engine bay.

Posted by: DRPHIL914 Dec 22 2019, 12:33 PM

Looks like you are covered! Should be taking out the vibration sound transfer as well as reduced thermal transfer. I wonder what the comparison of dB at compatible speed and rpm would be for your before and after - with/without?