3M sound deadner vs dynamat etc.

[Michael F.]

anyone tried the 3M sound deadner instead of dynamat/hush mat for noise reduction in car, how about lizzard skin product??? thanks.

[Joe R.]

Re: 3M sound deadner vs dynamat etc.

Michael,

I use neither as there is an insulating material sold at Lowe's that I like and use. It's about 1/4" thick and has aluminum foil on both sides so there is no problem using 3M upholster spray adhesive. It comes in a large roll and you have to cut it to fit but that's no problem either. Used it on several cars and it keeps the heat on the outside of the floor tunnel and the sound there also.
Please try it and report back as others may want to consider using it. Saves a lot of money and works well. You'll find it in the insulating department at Lowe's.

JR

[Gary C.]

Re: 3M sound deadner vs dynamat etc.

Joe Ray,

That type of radiant barrier was tested for my 2008 Restorer Article. See results chart below.

The radiant barrier did better than some of the others. Didn't test DynaMat. After talking with their Tech Support to get any floorboard heat reduction, two different types of their layers had to be applied and that made it took thick to be unnoticeable under the carpet for judging.

Gary
....

Floorboard Insulation Field Test
Brand	Floor Board Interior Surface Temp	Material Surface Temp	Temp Drop Floor to Top Insulation	Temperature Reduction Percentage
Corvette Central Ceramic Heat Barrier Kit	172	130	-42	24%
Kool Mat	175	162	-13	7%
Kool Mat with foil on floor side	176	159	-17	10%
Energy Q Radiant Barrier	170	102	-68	40%
HushMat	174	100	-74	43%
Notes:
1 - Floorboard temp reading taken after car drive 4 hrs
2 - Insulation temp reading taken after car driven 4 hrs
3 - Temp measurements made with Raytek MT4 MiniTemp
4 - Outside temperature 96~100 degrees
Floorboard Insulation "Kitchen" Lab Test
Brand	Cookie Sheet Temp	Material Surface Temp	Temp Drop Floor to Top Insulation	Temperature Reduction Percentage
Corvette Central Ceramic Heat Barrier Kit	199	134	-65	33%
Kool Mat	196	170	-26	13%
Kool Mat with foil on floor side	194	168	-26	13%
Energy Q Radiant Barrier	194	90	-104	54%
HushMat	195	86	-109	56%

[Ed S.]

Re: 3M sound deadner vs dynamat etc.

Gary,
Thanks for posting your test results - very telling. A question for you (or perhaps others) from your comment about two layers of Dynamat would probably not pass judging, do I understand that some types of after market insulating materials would pass judging? For example, your HushMat results are really impressive, if used under carpet would it pass judging? I understood that judges would peek under carpet where it can be rolled back without removing and if there was evidence of non-stock products there would be a point deduction. Can you or someone explain the judging rules on the use of after market floorboard insulation.

[Joe R.]

Re: 3M sound deadner vs dynamat etc.

Ed,

I was under the impression that the judges are told not to touch the parts that they are judging but ask the owner to open, remove or demonstrate what the judges need for a visual inspection.
Maybe I'm wrong in that assumption but maybe that's the reason I don't have cars judged anymore.
Could the new head judge clarify this point?

JR

[Gene M.]

Re: 3M sound deadner vs dynamat etc.

The judging reference manual makes no provisions for removal, opening, etc except the pieces noted for removal in flight judging. Roy had made mention of specific items not to be opened or removed for judging in the Driveline a while back. I don't know if this has been added to the judging reference manual but is to be considered judging law. I too await Dave's call on lifting up carpets (back floor behind seats) in loose areas. This is a new one! Supposed to be a visual call no disassembly required.

[Mark E.]

Re: 3M sound deadner vs dynamat etc.

I just installed 1/2" Dynaliner on top of Dynamat (per manufacturer's instructions) on the floors and tunnel. The carpet still fits ok, but the carpet is a more cushioned because of the Dynaliner. Is that a problem for judging? Dynaliner also comes in 1/8" and 1/4" thickness, so that may make the carpet feel less cushioned.

Either way, it's definitely noticeable if the carpet cut out flaps for the seats are pulled back or the ashtray is removed.

The car isn't roadworthy yet, so no feedback about Dynamat's effectiveness.

[Mark E.]

Re: 3M sound deadner vs dynamat etc.

I've learned most mods have unintended consequences.

The extra thickness of the 1/2" Dynaliner means that the seat and seat belt bolts are now too short. So I purchased a set of:

- Used OEM "long" seat belt bolts on ebay; see photos. Apparently some GM cars used a longer version of this shoulder bolt. They even have the "LL" head marking.

- Reproduction 78-81 Corvette seat bolts, which are apparently the same as the 1970 bolts but about 1/2" longer.

When they arrive, I'll let you know if this works.