| mobybrz |
09-04-2013 11:45 PM |
Quote:
Originally Posted by mrk1
(Post 1184451)
swain tech white lightning is a great and very durable coating.
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Swain is the only company I would use to coat anything (actually there is one other but they are European). Swain was local and helped our FSAE team out when I was in college and are great. Great customer service, great GREAT products. We did a test at one point, where we coated the primaries in swain, the collector and secondaries in Jet-Hot and then the muffler was left alone. The swain primaries were only 75C above the muffler after a bunch of autocross testing. The Swain section was 150C cooler than the Jet-Hot despite being upstream (external surface temperatures). :party0030: I have no data to support it, but I would suspect the coatings are more effective, how much I don't know.
Quote:
I've heard heat-wrapping headers on cars is a bad idea... Apparently shortens the life of the pipes.
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From a theoretical standpoint, both wrapping and external coating will increase the temperature of the metal in the headers which will potentially decrease the lifespan. Both of those methods are employed to keep heat in the header and out of the engine bay.
The heat still exists though and either goes out of the tail pipe or stays in the metal. Effectively, you change the equilibrium temperature distribution which leads to hotter metal and less escaping heat. The reality is though that I don't think any NA header outside of F1 or LMP is operating anywhere near the point where the stress on a properly designed header (room for thermal growth, properly supported, square and flat) where the temperature difference matters.
http://www.ssina.com/images/hotchart.jpg
The heat-wrap has a possibility of being worse if it does retain moisture. Even stainless isn't impermeable to corrosion, especially from Chlorine/Salts. Further, the increased temperature of the metal under the heat wrap would increase the rate of corrosion. The reason it came into use in racing before coatings was a combination of availability of the coatings and the ability of the wrap to be removed for maintenance and inspection. On a race car; the service intervals, stresses, and inspection routines are such that that matters.
There is also no reason you couldn't do both, it would probably just have minimal added efficacy.
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