Heat Noise Insulation

[Gary]

Looking for feedback on heat and noise insulation.  What are your favorites.  Doing a C1 corvette restomod, and thinking about Lizardskin ceramic heat insulation underneath and Hushmat on the inside.  Then I see it comes in 1/8 1/4 and 1/2 inch thickness.  I was thinking maybe 1/2 inch on the floor and firewall and 1/8 inch in the doors. Anyone have any experience with it or any of the other brands.

[anlauto]

I'm listening in on this one too....looking for a recipe for the Challenger resto-mod I got going... 

[Dakota]

On my Challenger, I used up some Dynamat I had purchased about 8 years earlier for another car project but hadn't installed.  I believe it was roughly 3/16" to 1/4" thick. It's advertised more for sound deadening than heat, but it seemed to work well for both.  That said, I probably would've used the Lizard Skin products if I didn't already have the Dynamat as I think the technology is better with Lizard Skin. 

[GoodysGotaCuda]

I wrote this on my facebook page a while back.

Start Here.
Noise frequencies are something that I am not an expert on, but I will do my best. I'll refer to two buckets, high frequency sound and low frequency sound. From there, I'll bucket it again, your high frequency sounds will be your tire noise and aero noise. Your low frequency sounds are more powertrain-born, engine, driveshaft, panel resonance, etc. Sometimes you can try to separate these by paying attention to wind direction when you hear the sound, or putting the car in neutral/idle at highway speed, etc.
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Seal the holes in the ship first.
The first and easiest method to cut down sound transmission is closing up –all- existing holes in a cabin. The smallest hole in a firewall can transmit an enormous amount of sound to your ear. This sounds simple, but you'd be amazed at what small details are left at the end of the build that are never properly addressed.
A grommet, a small bead of sealant, foam tape, etc. are all effective ways to seal off components at the firewall. Your brake master cylinder, steering column, speedo cable, clutch linkage, throttle linkage, heater lines, a/c lines, etc. all need to be adequately sealed off as they pass through the firewall. Don't skimp!
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Targeting high frequency sounds
This is where your open cell foam and closed cell foam come into play. I prefer open cell foam wherever it makes sense to hide it to help trap those high frequency wavelengths. The foam lets the sound bounce around within it to help keep it from propagating. As with anything, trying to dampen it nearest to the source is better. My front and rear wheel wells are foam lined to help combat tire noise. Above the headliner is also open cell foam adhered to the roof.
Also take some time to go around your exterior and look for aero noise contributors. Painters tape can be very helpful here, you may find loose trim, air gaps in the trim, mirror holes, wipers, etc. contributing more than you expected. Aesthetically you may not want to change something, but identifying some sources is helpful to know what you have to live with, and what you can fix.
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Targeting low frequency sounds
Successfully isolating the engine and driveline from the body is extremely important. People like to stick poly mounts on all things and go down the road, the amount of NVH they transmit is remarkable. If possible, start with rubber mounts and tighten things up as –necessary-, not the other way around. Also be absolutely sure your engine components aren't touching others, such as the headers to chassis or steering box, hard fuel lines going from the engine to chassis, solid mounted fuel pumps, etc. I left some on the table by using rod end front suspension joints [Hotchkis], that was a conscious sacrifice in NVH in trade for reduced suspension compliance.
Second is dealing with panel resonance. Large flat areas can be prone to drumming as the chassis excites it, this is where strategically using a butyl mat [Dynamat] can be beneficial. I am not a fan of covering an entire car in Dynamat. Not only is it remarkably heavy, but it only addresses panel dampening and it is not very thick. In all, I probably have 5-8sqft of Dynamat placed in various locations around my firewall, floors and doors. It's a good tool, but I won't peanut butter spread it all over a car.
Third, is using a sound dampening material, this is your jute padding, Lizard Skin, mass loaded vinyl, etc. Low frequency sounds need to be dampened with mass and the thicker it is, the better it is. I have basic jute padding under my carpet and have plans to add mass loaded vinyl on top of it in the future when the seats come back out for some reason. Mass loaded vinyl is the weapon of choice by those with competitive sound systems trying to keep low frequency [bass] inside the cabin. Unfortunately, it is quite heavy, but you need to decide which is more important to you, weight or all-out performance. If nothing else, at least it's weight is low on the car and central to its center of gravity.
Lastly is exhaust drone. You can make noise without the drone. Off the shelf resonators can provide some relief to an exhaust system, but it's effectiveness is very subject to placebo effects. "I put one on, so it must be better".
I chose to attack exhaust drone with Helmholtz resonators. There are various designs out there, this is also why those OEM mufflers are just so massive. The air chambers within them cancel out certain problem frequencies so that they go unheard without restricting flow. The J-tubes shown on my exhaust are around 2ft long and target the 1,400-2,000rpm cruising range and they made a substantial improvement on my drone. The cutouts you see only open during low vacuum conditions, the resonator J-tubes are closed at cruise, which is how the Helmholtz resonator works.
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In the end, this is not a cool subject that people see when they check out your car, but it matters to you. It provides that extra separation of a built car to a well-built car. I have room for improvement, but at a 70mph cruise it is phenomenal for a old car. It's comfortable to carry a conversation, listen to the radio at reasonable volumes, but yet it still rips when the vacuum cutouts open up

[GoodysGotaCuda]

thermal management. With being in the middle of Summer I figured I would share a little of what is behind the scenes and what makes this car extremely comfortable to drive in both hot and cold temps.

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First is sprayed insulation.

The sole source of thermal insulation from halfway up the firewall to the furthest edge of the trunk is LizardSkin
ceramic coating. You can [and should] top coat this, but it has been an excellent performing product for me. In addition to the bottom of the car, the entire underside of the roof is as well. This is also a huge source of solar loading when the car bakes in the sun. It's extremely lightweight and I believe is a significant contributor to maintaining comfortable temps.

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Second, and perhaps the most noticeable improvement is ceramic tint on all of the glass.

For around $500 I was able to have a 72% tint installed [as clear as possible] which provides a 99% reduction in UV rays and [most importantly] an 87% drop in Infrared Heat Transfer. An added bonus is the glare reduction that also comes with it, most noticeable through the windshield.

The car is noticeably cooler when sitting outside in the sun versus my 2016 WRX. It is also much more comfortable when driving where the sun is beating down on your arms or chest. The feeling of heat coming through the glass no longer exists.

An added bonus is the 99% UV reduction, consider what that will do to help your plastics, dash and seats last longer.

It's a light enough tint that you wouldn't know it was tinted unless I told you.

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Third is the most basic, mitigating air leakage.

Mitigating air leakage not only mitigates sound transmission immensely, but also serves as a thermal barrier.

The doors and window regulator access holes are covered in a sealed thin plastic barrier, which is underneath an aluminum backed closed cell foam insulation pad. I want the conditioned air staying in the cabin, not leaking out.

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Fourth is the obvious improvement of aftermarket air conditioning.

Being a non-a/c car I used the Vintage Air retrofit kit for under the dash along with the stock Hemi compressor. I have also tweaked the evap temp probe to thinking it's warmer than it actually is to increase compressor cycle times, resulting in lower evaporator temperatures. See Less