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Header wrap is supposed to reduce under hood temps, then explain this. I have my headers wrapped with the fiberglass wrap, wrapped correctly, and for the heck of it I got out the laser temp gun. I point the laser at the narrow section of unwrapped header pipe where it comes out of the head flange got roughly 280 degrees on all the pipes. Then I dropped down a couple inches onto the wrapped section and every pipe read 125-175 degrees hotter. What's the deal?
 

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From my understanding, it's suppose to contain the heat within the header. So the surface temperature will be higher, however, radiant heat is reduced.
 

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T/S 368E
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That's weird, because mine is as predicted, wrapped is cooler, much much cooler.
Every where the tubes are wrapped the diaper is fine, where it's not, the diaper melted!!


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Header wrap is supposed to keep the exh pipes hotter. This keeps the velocity of the exh gases higher for better scavenging...& more hp.
 

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Header wrap is supposed to keep the exh pipes hotter. This keeps the velocity of the exh gases higher for better scavenging...& more hp.
So if I understand you correctly you are saying wrapping the headers can make more power?
 

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So if I understand you correctly you are saying wrapping the headers can make more power?
Higher temperature = higher velocity.
 

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Not sure how heat guns have evolved in the last few years, but they used to have a calibration setting called "emissivity". If you point your heat gun on shiny silver surfaces, like the head of a bolt or chrome ceramic header coating, compared to a flat black surface, you will not get accurate readings unless the emissivity is calibrated for that specific surface.

Try testing the surface temp with a surface temp gauge...like from an EGT meter like you use for exhaust temp in your headers might work. Maybe tempil sticks
 

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Not sure how heat guns have evolved in the last few years, but they used to have a calibration setting called "emissivity". If you point your heat gun on shiny silver surfaces, like the head of a bolt or chrome ceramic header coating, compared to a flat black surface, you will not get accurate readings unless the emissivity is calibrated for that specific surface.

Try testing the surface temp with a surface temp gauge...like from an EGT meter like you use for exhaust temp in your headers might work. Maybe tempil sticks
Better idea to try...paint a small area of your header tube the same color and flatness as your wrap, then retest...
 
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