Catalysts retain lots of heat, so that may be the reason the header gets so hot.
When the coating flakes off like that, in those places there is no heat shielding.

 

Are we sure the coating has completely flaked off there? If it was completely gone, wouldn't it appear more like the bare stainless steel you see on the collector in that photo? Mine don't look exactly like Aualexa2's but in a few places show some discoloration. I don't feel much thickness change where the discoloration has occurred. The coating is around .010 to .015" thick nominally so if it were gone completely, that would be easy to feel with bare hand.

 

Yes, I'm referring to aualexa2's picture, which is bare stainless and not just discolored.
At the upper left of the frame the crack between the coating and the metal can be seen more clearly.

 

Yeah, I saw that flake, but the darker gray surface underneath doesn't have the texture of the bare stainless steel tubing so wondering if that indicates only a surface layer of the coating has come off. Or does the bare stainless tubing have its appearance and surface texture altered by application of the ceramic Swain coating?

 

They abrasive blast the metal before coating, that may be why it looks like that, and between the runners it looks like the coating has burned off instead of flaking.
The area could be scratched with a screwdriver to see if it looks like a bare metal scratch or not.

 

Here's a link to stevencr's FS ad for his headers. I have no relation to him, but checked out his post when he responded to this thread. He has the same flaking (mine look like bigger flakes have come off) and Swain told him the coating is still effective.

https://rennlist.com/forums/parts-ma...l#&gid=1&pid=4

 

I guess it could be said that overall the coating is still effective, but a flaked area would be all the way through and therefore ineffective.
As a test, the coating can be scratched with a screwdriver and it will look like a crayon mark across it's rough surface, where scratched metal will instead be a sharp line.

 

Before I start scratching stuff, I'll wait and see what swain says. I know they told Stevencr that his coating was fine, but I figure I'll ask them myself. I've sent them two messages through their contact page, and I'm waiting to hear back. Will update when I get in touch with them.

 

In my initial message through Swain's website, I asked them if there was an email address I could send a picture to. Below is the response I received. I've sent the photo to the email address the message came from, but no further response.

"We have one coating for exhaust parts which is primarily an external coating called White Lightning. It is an ugly coating which mars easily in normal shipping and handling, can be difficult to keep clean and can change color and appearance when in use. There are times some folks will see spike like growths on the surface of the coating and even times when the outermost layer can fracture. When the look of the coating is important our coating is not a good choice. When maximum heat insulation is important it is a great choice. If you are trying to manage heat and the look of the coating is not critical our coating is a great choice. It certainly is possible the outermost layer could fracture and peel."