ceramic coating versus stainless steel

[clutchdust]

I just read an article about header install on a c6. They installed stainless headers. Earlier this year I installed ceramic coated headers. I chose ceramic specifically for the thermal properties. The questions is, why doesn't anybody offer a coated stainless? I know the stainless is good for pretty much the life of the car but I don't think it has any thermal insulating properties. So unless it's all about looks, what advantage does SS have over a similarly built coated header? Will ceramic last as long as SS?
This just puzzles me.

 

[MYBAD79]

Any coating can get damaged over time, pain, powder-coat, ceramic, whatever.... That's why I chose stainless..... You can send the SS headers to for example JetHot - they'll coat SS headers..... Why nobody offers it?? Too expensive I assume.....

 

[69427]

Stainless steel only conducts heat at about a third to a fourth of the rate of mild steel. (Which makes it nice for headers and jet engine parts.) So essentially the thermal path of resistance (the insulation) through a stainless header is the full thickness of the header tube.
Ceramic coating that tries to stop/slow down the heat transfer through the mild steel tubes is damn thin (ie: the thermal path is short). So, unless you're able to know the ceramic thickness it's hard to do the math to compare ceramic coated mild steel headers to non-coated stainless steel headers. Ceramics do seem to be such good insulating material that a thin coat of it is as good (or better) than a "thick" layer of stainless.

The math is easy, but I haven't found any "clean" info on ceramic material thermal conductivity and typical thickness on headers to be able to generate some actual numbers to compare.

 

[CCPcoatings]

Ceramic Coating Stainless Steel Headers

I just read an article about header install on a c6. They installed stainless headers. Earlier this year I installed ceramic coated headers. I chose ceramic specifically for the thermal properties. The questions is, why doesn't anybody offer a coated stainless? I know the stainless is good for pretty much the life of the car but I don't think it has any thermal insulating properties. So unless it's all about looks, what advantage does SS have over a similarly built coated header? Will ceramic last as long as SS?
This just puzzles me.

There are several manufactures that offer ceramic coated headers as options. The primary reason you don't see them as a standard offering is due to the increased cost. You're already paying a significant premium for SS so most don't realize the advantage to ceramic coating them, nor do they want to pay the additional cost. More importantly, most people buying SS headers are doing so to prevent corrosion / rust through so SS fits the bill "initially". I say initially because most SS owners soon realize that their bright shiny headers actually oxidize, rust and discolor rather quickly. They won't rust through anytime soon like mild steel, but the discolored and oxidized appearance is what forces most to ceramic coat them at some point in the future (see below).

Technically speaking in many cases SS does offer some thermal advantages over mild steel as well as offering increased durability, corrosion resistance, etc, etc. Quantifying and or realizing any thermal advantages from SS gets much more difficult. The first problem is comparing a specific steel alloy to a specific SS alloy and the wall thickness and diameter of both. In many cases manufactures will reduce gauge thickness in a SS headers vs a comparable mild steel header. They do this because the SS is stronger, and can be made lighter with the thinner gauge material and still remain as strong or stronger. Thinning the tube will also reduce its thermal properties.

Outside of all the technical debate and possibilities of combinations, the biggest complaint I hear from people that have switched SS headers from mild steel headers is that they are HOT, subsequently increasing underhood and floor board temps. The reason for this is because the denser SS holds the temps in the substrate longer as opposed to the mild steel dissipating the heat more rapidly. So in most situations the best case scenario is to ceramic coat the SS headers if it's in your budget. The SS offers superior strength and corrosion resistance and ceramic coating the stainless steel headers offers improved thermal control while eliminating the oxidation issues.

409SS headers - SBC Truck


POLSHED 304SS Exhaust - Ferrari F-430

 

[Ralphy]

Then there's inconel.$$$

Ralphy