Actually the base material and wall thickness do have an added effect on the outcome in terms of temperature. The ceramic coating process does not “stop” heat transfer; it simply reduces it. The overall reduction in radiant heat is different on stainless versus mild steel when ceramic coating is applied, based on what the heat radiant was without the ceramic coating. Stainless steel naturally retains heat more than mild steel. Ceramic coating over stainless would give the benefit of spreading the heat load out and allowing better dissipation and reduction. When combined with internal/external ceramic coatings, you’re changing the effective outcome. Engine state-of-tune (stock or modified) also naturally plays a part in overall radiant heat emitted and effectiveness as such. Heat dissipation and the appearance of any discoloration would be the benefits over stainless steel alone. Definitely one of the best combinations utilizing stainless steel and ceramic coating.
The internal/external ceramic coating is the same from a primary function standpoint between the two (stainless and/or steel). The mil thickness would be very close to the same as well, although the surface roughness is greater with the steel satin finish. Polishing operations may compress the mill thickness very slightly. Polished will give better performance in terms of corrosion (salt spray resistance, etc.), but both perform about the same in terms of temperature reduction as compared to the base bare metal makeup. Cosmetically, the unpolished finish is a result of simply not doing the further media operations required of “polishing” the surfaces. There are performance benefits to polishing the surface, but then we start splitting hairs on that subject matter if we get away from the “polished finish just looks better” preference.
The mild steel offering is a high quality, lower cost alternative. Being mild steel, it requires some kind of coating to prevent corrosion. Sure, it could have been simply painted. But the goal was never to make a “cheap” pipe as compared to the stainless steel offering. It was to offer a lower price point option, while also addressing heat barrier options since mild steel tubing will have a lower life span from heat-cycling fatigue without a barrier applied. If you only coat the outside (as many companies do) radiant heat will be lowered slightly, but you will further shorten the lifespan of mild steel from the “inside out”. So the inside “surface” must have that issue addressed on a quality product. Yes, it’s more expensive to also coat the inside, but by our standards, that is not an option; it is mandatory. Obviously the mild steel tubing/head pipe is significantly easier to work with; all the way from cutting to bending/forming, sanding, welding, one set of bungs, etc. And of course material costs are lower. No big mystery there. Once again, passing those cost savings along to the customer who desires a more competitive price point (from the stainless/ceramic combo option).
So the bottom line is – lots of benefits from ceramic coatings being applied to whatever the base material is; cosmetic, performance, lower temps, corrosion protection, etc. The primary benefit is significantly lower radiant heat. And on a big air-cooled v-twin engine with head pipe tubes in close proximity to your lower extremities, that’s always going to be a good thing.
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Topic: Exhaust SS vs Mild steel (Read 18631 times)