On stainless steel it's usually ok (unless it's some low grade stuff), but on mild steel life will be greatly diminished...IIRC, certain types of heat wrap can shorten life of exh pipe.
Yep. The heat wrap can/does trap moisture in the wrap and then when the pipes cool, the moisture condenses out onto the metal causing corrosion. It even gets to stainless steel (although obviously not a badly as with regular steel). The heat cycling of the exhaust just makes it worse.IIRC, certain types of heat wrap can shorten life of exh pipe.
I've heard this also, but how do you thermal coat just a portion of a particular part? Seeing as the coating is applied to both the inner and outer surfaces of the steel, how do you go about this for something like a cat?Yep. The heat wrap can/does trap moisture in the wrap and then when the pipes cool, the moisture condenses out onto the metal causing corrosion. It even gets to stainless steel (although obviously not a badly as with regular steel). The heat cycling of the exhaust just makes it worse.
The best thing to use is ceramic coating - if possible send the pipe out to be coated by someone like Jet-Hot, or such. That will provide the heat protection without the possibility of corroding.
You don't have to coat the inside and outside - it actually usually costs more to coat the inside. Coating the inside protects the metal from rusting away better (as well as helping to contain the heat) but isn't necessary. I don't know that you need to coat the cat, most cats have insulation of their own (double housing, heat shields, etc.) but it would seem that you could coat the outside without much problem if you desired. Most people use ceramic coatings for the headers, pipes, etc. - the same things that people tend to want to wrap.I've heard this also, but how do you thermal coat just a portion of a particular part? Seeing as the coating is applied to both the inner and outer surfaces of the steel, how do you go about this for something like a cat?
