Heat Management

[mustanghammer]

If you have a subscription to Motortrend+ you might want to check out this episode of Engine Masters: https://www.motortrend.com/plus/deta.../5209849/30774

To summarize they tested various heat barrier materials on a piece of 22 gauge sheet metal place next to a header that was producing 960F heat for 30 seconds. Not all of the materials worked very well and a couple of them were worse than the bare sheet metal baseline test. The conclusion was that insulation that was multiple layers and or incorporated some air pockets worked the best. The fancy gold stuff was not good at all.which is a bummer because it is soooooo pretty.

They also tested three types of header wrap. All of them cut header heat about 150F with no difference in the type or wrap used. In the past they have tested header wrap to see if it adds power, which is a claim that header wrap manufactures have made since this stuff was introduced. Their testing showed absolutely no HP increase from the use of header wrap.

My conclusion from their testing is that if you use the right insulating material you are better off insulating the stuff you want to keep cool. So the air box, intake pipe, sides of the differential, etc. Wrapping the header/exhaust is going to knock down a portion of the heat but not all of it. So maybe header wrap in combination with insulation applied strategically around the exhaust should net the best results.

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[NightmareMoon]

well you don't want to keep the heat inside the diff either, so insulating the diff itself is probably is a bad idea. It needs to radiate.

 

[mustanghammer]

I insulate the rear axle and brake lines on my RX7 that are near the exhaust. The rest of the housing isn't insulated. The idea is to shield it near the heat source.

 

[Optimum Performance]

Dropping the header heat radiating into the engine compartment and everything around it will limit ambient temperatures which is my issue with these videos. They steer the data and testing based on assumptions and that results in faulty test procedures. Wrapping headers on an engine in a dyno cell will do nothing, in a cramped engine compartment it will do much more.

 

[WD Pro]

Was there any mention of ceramic coatings ? (not the aesthetic / bodywork type lol).

WD

 

[Optimum Performance]

Was there any mention of ceramic coatings ? (not the aesthetic / bodywork type lol).

WD

Back in the '90's we used Airborne coatings for headers, turbine housings etc. It was obvious how much heat was contained from the coatings. Just the old trick of placing your hand near an uncoated header vs a coated header you could get to 1-2" before feeling extreme heat. Lighter colors tend to be better than dark colors.

 

[mustanghammer]

Dropping the header heat radiating into the engine compartment and everything around it will limit ambient temperatures which is my issue with these videos. They steer the data and testing based on assumptions and that results in faulty test procedures. Wrapping headers on an engine in a dyno cell will do nothing, in a cramped engine compartment it will do much more.

The value of the test was to determine the temperature drop on the back side of the material that is exposed to the heat source. Such as the passenger side of the firewall or floor. They even said as much at the beginning of the episode. For the header wrap portion of the test, they were trying to see if the different types of wrap made a difference. They all worked to the same extent.

As you said, you would really need to test header wrap in a real car. But not all cars have the same amount of space in the engine compartment and or the same amount of air flow in the engine compartment. So results would be limited.

Personally, I don't like header wrap and wont use it. I have seen it prematurely degrade exhaust components and it is no fun to work around - itchy fiber glass crap.

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