Engine insulation for hybrids to improve fuel economy

[Phase]

https://www.secondskinaudio.com/heat-shield/


any opinion on whats the best product for engine insulation from this company?

[Talos Woten]

Originally Posted by Phase

https://www.secondskinaudio.com/heat-shield/


any opinion on whats the best product for engine insulation from this company?

The only ones you could use are the Radiant Shield and Firewall Ceramic. The others are only rated to 250F, which is too close to engine running temperature. I expect the Radiant Shield won't do much; you are looking for resistive insulation rather than reflective. That only leaves the Firewall Ceramic, which is rated to 400F.

Just FYI, I got a mat of mineral wool Cerablanket off Amazon rated to 2000F for a third of the price. If such things matter to you.

[Phase]

Originally Posted by Talos Woten

The only ones you could use are the Radiant Shield and Firewall Ceramic. The others are only rated to 250F, which is too close to engine running temperature. I expect the Radiant Shield won't do much; you are looking for resistive insulation rather than reflective. That only leaves the Firewall Ceramic, which is rated to 400F.

Just FYI, I got a mat of mineral wool Cerablanket off Amazon rated to 2000F for a third of the price. If such things matter to you.

it says the mega block sheet goes to 1000f?

[Talos Woten]

Originally Posted by Phase

it says the mega block sheet goes to 1000f?

If you look closer down the Mega Block page, it says the foil shield is only good until 450F. That's consistent with the working temperature of melamine foam:
https://melaminefoamtech.com/melamine-foam/

It says it requires 2" clearance to go to 1000F, which is completely misleading advertising. Personally, I avoid any product that tries to oversell itself. But it's your purchase decision.

Is there a reason why you are limiting yourself to this particular company? Employee discount, or a great blackmail situation with the manager?

[Phase]

Originally Posted by Talos Woten

If you look closer down the Mega Block page, it says the foil shield is only good until 450F. That's consistent with the working temperature of melamine foam:
https://melaminefoamtech.com/melamine-foam/

It says it requires 2" clearance to go to 1000F, which is completely misleading advertising. Personally, I avoid any product that tries to oversell itself. But it's your purchase decision.

Is there a reason why you are limiting yourself to this particular company? Employee discount, or a great blackmail situation with the manager?

just good experience with their jute thermal insulation i used for the interior of the cabin. they have high quality products and good customer support

though they did try and push me hard to get their sound deadener, but i went with kilmat from amazon instead. second skin and dynamat have some of the elite products, but are overpriced. i dont mind trying something cheaper that works and has great reviews, hence why i chose kilmat over dynamat lol

[freebeard]

duckduckgo.com/?q=basalt+fabric+engine+compartment+insulation&ia= web

https://www.heatshieldproducts.com › marine-heatshield › marine-heat-shield-insulation
Engine Room Insulation | Marine Heat Shields | Heatshield Products
For heavy-duty engine room insulation, it's hard to beat our Lava Shield Mat. This adhesive heat shield is made of basalt fiber and is naturally resistant to the weather, moisture, chemicals, and even acid. Perfect for the engine room on your craft! Keep the Operator Compartment Cool With Our Marine Thermaflect Cloth

www.bafanet.com › anwendungen › ?lang=en
BasaltFaserNetzwerk | Textilien from Basalt - Anwendungen
Applications of the basalt fiber" Basalt fabrics are everywhere, at the point where it literally sizzle - in industrial exhaust systems or in the engine compartment of vehicles , for example . Basalt fibers withstand temperatures up to 800 ° C .

That's 1472 F.

[Xist]

I remember members arguing about this.

I found this from 2009: Developed for winter commuting (but now I run 'em year around)
Frank Lee cut a sheet of cardboard and put it under his car hood and used 1" foil-faced foam in his truck.

Originally Posted by Daox

Hey Frank Lee. Any chance you could find your old pictures and host them on EM? I'm looking to add this thread to the 65+ mods list and pictures really are helpful.

#23 11-30-2017

Daox posted Super fast warm up mod - Engine insulation in 2011.

The fifth post is Frank Lee sharing his older thread.

The argument I remember is that cardboard and coroplast have negligible insulative properties.

I also remember people putting fiberglass welding blankets under their hoods, but I will need to finish that thread and possibly look elsewhere later.

[CigaR007]

I use a fibreglass fire blanket and it holds up well in my CR-Z. It reduces the warmup time and retains engine heat for longer periods. Works great in tandem with an engine block heater too.

[Talos Woten]

Originally Posted by Xist

The argument I remember is that cardboard and coroplast have negligible insulative properties.

Thanks for all the helpful links, Xist! I thought I couldn't have been the first person to think of using more insulation in the engine bay. It seems like such a straightforward idea.

As for the insulation, it's often misunderstood about how it works. The R-Value of dry, non-circulating air is ~ 3.5 per inch. All it takes is a sealed envelope to achieve that, and that's how the vast majority of insulation works. It's how fur keeps animals warm, sleeping bags are disproportionately effective, aerogels offer insane protection, etc.

When calculating the effective temperature drop, we need to account for the static air gap as well as the actual material itself. So while a 3/16" of cardboard is only R 0.05ish, if it traps an inch of air then its really 3.5 or so.

This is significant when calculating the flux of heat through the surface. Metals have very high heat transmission properties; it's why stuff like copper and aluminum are used at heat sinks. The heat flux is a function of the temperature delta between source and sink. So the smaller one makes that (say, through insulation) then the smaller the thermal flux becomes. Optimally, one wants exactly enough insulation so that we have the engine operating temperature on one side and ambient on the other, with no flux through the surface.

By the way, there are more subtleties to insulation. We've been talking about resistive insulation, which blocks conduction. But there's also reflective insulation, which blocks radiation. And trapping air is effectively blocking convection.

Hope this helps!

[Talos Woten]

Originally Posted by CigaR007

I use a fibreglass fire blanket and it holds up well in my CR-Z. It reduces the warmup time and retains engine heat for longer periods. Works great in tandem with an engine block heater too.

Yah, this is a very easy experiment to perform for doubters. Most people have access to their coolant temp, and insulating the hood is a low cost and time test. As I like to say, "the proof is in the pudding." Go out and actually verify whether things work or not.