Light wt. padding/dampening
 

This might be useful for those who (like me) are working at getting some sound dampening -- but with the least possible wt. penalty. BTW, viscoelastic meands that the material is designed to transform the pressure (sound) waves into thermal energy and dissipate the sound that way -- instead of the older means of dampening which was to shift the resonant frequency of the car's body (or components) -- the "drum" that we sit inside of -- to a lower, inaudible freq. by adding wt. to the panels (such as the original lead Dynamats).

I have not tested any of the numerous materials out there, but this co. weems to have its techinical s*** together. See:
http://www.quietcoat.com/html/technology_overview.html

Here are some notes from an Email exchange I had with the
company's founder re the lightest wt. sound dampening material:

For your application, use 12.58 lbs/gallon wet, 11.67 lbs/gallon dry.

For maximum noise damping, and from experience, we suggest you focus on thee
following, approximately in this order of importance:

1. Gearbox if your car has one (the material is effective to 200 degrees F,
survives to 350 F)
2. Firewall
3. Wheel wells
4. Floor
5. Undercarriage
6. Hood
7. Trunk
8. Doors

You can do the forensics to figure out which areas are going to give you best benefit/cost. You don't need 100% coverage to benefit from the viscoelastic damping effect. If you have CAD and MatLab, you can figure out where the resonance points might be and hit those hard.

The material performs extremely well as a fire-flame retardant. See attached FAA/FAR test result. We scored perfect zeros - cannot get a better result.

The NK-118 product is an extensional layer (coating).
The NK-311 is a constrained layer (adhesive).

Proper application is 3 coats, 13.3 sq.ft. per coat. However, if your
application requires minimal weight, you can experiment in two dimensions:
reduced coverage, reduced coats. Viscoelastic damping properties will be
felt at 50% coverage, single coat.

Randy-
In my case, wind seems to be the primary noise problem. Are you looking for a way of reducing weight without a noise penalty, or is your car free from wind noise to the extent that this kind of sound proofing is appealing? I'm just curious as to what is possible.
-Scott

Noisekiller sound like the same stuff.
-Chris

Given the patenting involved, I am sure that Noise Killer is NOT the same. The problem I have with them is that they don't have the same technical backup on the product -- so the QuietCoat seems a safer bet, IMHO.

re wind -- I put the opening F vents on my '73 - so I will be less able to reduce wind noise. It's not horrendus right now. I am focused on the sound pad area on the engien firewall since I'm aobut to do an engine swap. Window sealing later. But each owner needs to listen carefully for wind vs. tire vs. grit/debris hitting the panels noise modes and do the worst one first.

"NoiseKiller is a patented spray-on sound and vibration control, or liquid sound deadening. It literally removes unwanted noise and vibrations by converting them into low grade heat."

They sound so similar I wonder if NoiseKiller is reselling QuiteCoat's stuff or using their patent (or vice versa)?
-Chris

Have 2 gallons of QuietCoat on order. I will probably get it by the weekend. So, I'm thinking of spraying this stuff in my wheelwells and the next area is the firewall. The guys at Quietcoat recommend the engine side vs. interior if you are only going to do one side. Engine drop? Ugh, never dropped a 911 engine before (have done a 912E before). I hope this does not turn into a "while I'm in there" type of project, ending with a 3.6 conversion and ... :)

Any thoughts on applying on firewall vs. interior side? Interior side means I have to rip out the carpets and spend even more money on new carpets, while the exterior application means I have to yank the engine and tranny and pressure wash the surface. I am leaning towards exterior application. Besides, it would be better to stop the sound before it reaches all that tinny sounding metal, right?

I need to buy a dB meter now.

I thought maybe if I can get the car super quiet, I will install a dual-out muffler. However, today I had to show a rental property and I ran inside one house to lock up while the 911 was idling. I could hear the car rumbling through the walls. I only have a single out stock muffler with no catalytic converter (EURO SC model). Hmmm, dual out might be a bad idea. :)

BTW, how did I ever think I could drive a Porsche without spending lots of money and time on her??? This is like a disease, except there is no cure. :)

Jürgen

OREGON AERO’S PAINLESS AND QUIETER HEADSET UPGRADE HELPS BRUCE BOHANNON BE HIS BEST. Competitive aerobatics champion Bruce Bohannon can’t afford distractions in flight. So he depends on his Oregon Aero headset upgrade to eliminate noise and pain when he's in the cockpit. Says Bruce: "The difference in comfort and sound levels since Oregon Aero worked its magic on my headset is nothing short of fantastic!" Oregon Aero offers upgrades for nearly all civilian and military headsets on the market today, and the upgrades are customized for each specific headset model. Check out all of Oregon Aero's products online athttp://www.avweb.com/sponsors/oregon

I can't help but laugh at the thought of wearing a headset while driving. "OK, babe, you can ride, but you're gonna have to wear this headset if you wanna talk to me."

I am thinking more along the lines of a more complex solution - something that consumes more money and hours than most reasonable people would consider. To hear the stereo at a 'fun' volume, I have to turn it up so much my ears start to hurt after a few minutes. So, to save my ears, I need to lower the noise floor.

Jürgen

LOL! Also, I couldn't help but notice one of the applications in the original pitch: "gearbox, IF you car has one". HUHHHH????