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  #21  
Old 01-11-2011, 09:33 AM
bobadame bobadame is offline
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Here's a discussion on a Dynamat alternative.

http://www.nowroc.org/Techtips/Dynamat.htm
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  #22  
Old 01-11-2011, 04:18 PM
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heinke heinke is offline
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Default Insulation

Peter,
Thanks for bringing up insulation safety concerns.

The material I have is RMax Thermosheath-3. Turns out its made from polyisocyanurate foam (covered with aluminum foil) and is not urethane. I'm not a chemist so I don't really know what polyisocyanurate really is. I pulled the MSDS (http://www.rmaxinc.com/downloads/MSD...masheath-3.pdf) and under Health Hazards section it says, "No know acute or chronic hazards. Dusts generated from product are nuisance dusts. This product is not considered to be a carcinogen." Under Reactivity Data section it says, "Material is stable. Hazardous polymerization cannot occur." It also says, "Conditions to Avoid: Sources of flame and ignition."

The product data sheet (http://www.rmaxinc.com/downloads/Dat...rmasheath3.pdf) says it has service temperatures up to 250 degrees Fahrenheit and water absorption at <1% by volume. It also says it's non-hazardous waste that can be disposed of in a landfill.

From what information the manufacturer provides, it really sounds like fairly benign stuff. The main question I'm now asking myself is whether it would ever be exposed to greater than 250 degrees when behind .040 aluminum sheet?

Does anyone else have information or experience that would say if polyisocyanurate foam is unsafe to use in the application where I have it?
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  #23  
Old 01-11-2011, 05:23 PM
Landyplan Landyplan is offline
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Sorry for the slight hyjack,

Does anyone know of any UK alternatives to the mega expensive Dynamat?

Cheers
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  #24  
Old 01-11-2011, 09:15 PM
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Joel: Your aluminum firewall panels are going to far exceed 250 degrees. I did some seat time in this aluminum Buick v8 powered Sprite. The floor and firewall were aluminum. The engine had a "bundle of snake" exhaust system with the collectors above the bellhousing and the exhaust pipes running down the top of the tunnel and through the trunk. We had to add more insulation to the tunnel but the other panels had no insulation. The floor of the footwell was so hot that it turned the heel of my driving shoe into charcoal. Way beyond just melting the sole of the shoe. It was extremely painful to drive the car. I was almost relieved when the engine expired. Perhaps fiberglass ductboard might be a better solution. Stainless steel would also be a really good heat barrier.
Your engine is going to make a lot more heat than that little 3.5 liter Buick.
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  #25  
Old 01-12-2011, 12:31 AM
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heinke heinke is offline
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Default Insulation questions

Cary,
Thanks for the input.

All: Ok, so it sounds like the insulation I have will not be adequate for the firewall and tunnel areas. The question then is what heat rating will I need for these areas?

Here's what I have that will be producing the heat. The engine is 5.7 liters, supercharged and should produce somewhere between 550 to 575 horsepower. The headers are 304 stainless and have an air gap of about 3 inches to the firewall panels (at the closest point). The exhaust system is 2.5 inch diameter 304 stainless with stainless mufflers inside the tunnel (next to drivers & passengers thighs) with about 1 inch air gap to aluminum sheet inside the tunnel. Both these areas have 1.5 inches for insulation between the aluminum sheets.

Does anyone have an idea for how much heat will get to the insulation?

I did a quick scan of the McMaster-Carr (http://www.mcmaster.com/#flexible-ce...lation/=ajw2l7) online catalog and there are several options with different heat ratings.
  • Flexible Ceramic Insulation
    • calcium magnesium silica ceramic fiber at 1832 degrees
    • alumina silica ceramic fiber at 2000 degrees
  • Rigid Ceramic Insulation
    • Made of alumina-silica at 2300 degrees
Generally, the price goes up with the heat rating. So I'd like to get something adequate but not necessarily beyond what's needed.

Does anyone have first hand experience with how much heat this combination will produce and any of these types of silica-ceramic insulations?
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  #26  
Old 01-12-2011, 02:33 AM
Overkill Overkill is offline
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Default Insulation

Joel,

I've used the exhaust tubing wraps available from Summit and many others. It keeps the heat in the headers - to a degree.

No idea what this next stuff is called, but I see it at the Pleasanton Swap meets frequently and have used it a couple times. It's a white foam product, about 1/4" thick and has a silver backing. Guys demo has a propane torch burning on the stuff all day,and the other side of the metal is only slightly warm. Rolls of various lengths. One I've bought before is $100. Buddy has a new roll in his rafters (I had to replace the one I used) can look at it and see if there is any name on it if you'd like. The seller is a swap meet regular and may be at Turlock swap at the end of the month. Use spray adhesive to apply it. Last place I used it was on my AC plenum on the teardrop - and it worked great there. Used that expensive aluminum tape (available at Home Depot) on the corners. It's the same stuff you should use on that foam board you have.

The foam board you have is flame resistant, but like it says, only up to a certain temp. The aluminum side is meant to be a radiant barrier, reflecting radiant energy back. We used the same 1" product in the teardrop, taped the seams and now have trouble with it getting too hot inside from simply body heat. Have had to keep the windows open, even when it's snowing outside... Installing ventilation system in addition to the AC to compensate. Also, be aware, the radiant barrier must be exposed to air in order to work. People will install it face up on their roof, with felt paper in direct contact with the foil side - per everything I've read, you've just killed the radiant barriers effectiveness.

When the foam board is used in a residential or commercial application the code requires it be covered with a flame proof barrier - drywall - 1/2 inch minimum in living areas, double layer of 5/8 in garage (2 hour barrier).

Under extreme workout on dyno, engine you described will cause the SS headers to glow red.

Lastly, look in Street Rodder and other mags. There are a couple companies that specialize in insulation that may be able to help you out.

As you know, aluminum conducts heat well. Also, on two occasions now, I have seen concrete hardi board, or asbestos board, nailed to the wall behind wood stoves. There was a gap between the board and the wall, as is recommended. However, the nails went through the fire proof board, through the spacers and into the studs. The wood stove heated the nails so much, that they caught the studs on fire. Made for an interesting wake up call in the middle of the night. Thank god for smoke detectors. Just something to think about when wondering where the heat will transfer to.

John

Last edited by Overkill; 01-12-2011 at 02:38 AM.
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  #27  
Old 01-12-2011, 07:10 AM
TheRodDoc TheRodDoc is offline
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The best method would be to cover all exhaust to the back of car with ceramic fiber blankets. They have to be custom made to fit each part of system. These consist of the blanket with a woven covering on the outside of them for protection and to hold them together. From heads to toward back of tail pipe.

Then spray a ceramic coating on all sheet metal on heat side of firewall and tunnel. No insulation where your putting it. Then a blanket insulation covering interior.

We have diesel engines in our streamliner that are producing so much horsepower that we have melted inconel exhaust headers, pistons and the whole tops of some of the valves. The painted body is less then a inch from the headers and turbos, 4 of them producing 100# boost for each engine. We use the highest temp ceramic blankets available around everything. They contain all the high heat and send it out the tail of exhaust pipe. The paint on the body never even discolors. It Works.
We also use special ridged 1/4" thick ceramic sheets for some areas. I think this is a refractory insulation made for melting furnaces.

Don't use anything that can burn. We have had some fires in the streamliner when we melted the headers and it is amazing how fast the fire burns up things. In just 3 or 4 seconds most any thing burnable was gone. Even a section of the body.
(the blankets won't stand direct exhaust blast) The blankets won't burn but will just fall apart when heat retaining ability is passed.
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Last edited by TheRodDoc; 01-12-2011 at 07:32 AM.
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  #28  
Old 01-12-2011, 10:54 PM
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heinke heinke is offline
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Default Exhaust wrap

Ok, now that the feedback has suggested covering the headers/exhaust pipes, I looked at some of the suggested sources. I found a wrap made from "pulverized lava rock": http://www.designengineering.com/cat...-lr-technology

The description says, "DEI titanium exhaust wrap with LR technology is constructed from pulverized lava rock, extruded into fibers, and then woven into a tight weave, giving it titanium-like strength and toughness... is capable of handling direct continuous heat up to 1,800 degrees F and radiant heat up to 2,800 degrees F. And because it's pliable, there's no need to wet the wrap when wrapping headers or pipes, as many do in order to make the wrapping process easier to manage and to get a tight wrap. Titanium wrap will not shrink, and because of its material structure, it is more resistant to temperature and vibration breakdown, abrasions, and chemical and hot oil spills than glass fiber wrap."

Does anyone have experience with this product? Does it work well?
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  #29  
Old 01-13-2011, 01:05 AM
TheRodDoc TheRodDoc is offline
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We tried it back for our first runs. Not good enough. None of the (wrap type) insulation worked well enough. It wont stand enough heat.
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  #30  
Old 01-13-2011, 10:33 AM
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Is it too late to make the outer footbox panels out of stainless? Stainless is a very poor conductor of heat and that would go a long way to keep the heat from spreading to other panels.
Perhaps even some stand-off heat shields connected to the pipes to cut down the radiant heat. Make them of stainless and clamp them to the pipes with hose clamps.
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