Originally posted by DemonSVT:
I'd rather have coated steel then uncoated 304 SS. Every day of the week! Period.
Uncoated SS is horrible for heat retention and bleeds heat badly to the surrounding area. The more exhaust heat lost the worse the performance and the more heat introduced to the engine, oil pan, and under hood the worse every thing else is.

You can't wrap cheap SS because it will crack. I suppose you could send it in for Jet-hot coating. Then that seriously cuts into it's price advantage everyone harps about.


This is a classic example of you get what you pay for. If you want to save a little money and buy this blatant knock off design then at least get them coated. You'd be very foolish not to.



Sorry but there are a few misconceptions here.

304L stainless is normally just fine for high heat apps.
Stainless does NOT conduct heat as well as mild steel, therefore it will not remove as much heat from the exhaust.
The life of the mild steel or the stainless will be greatly reduced with header wrap and you will never know until the mild steel pipe has holes forming in it or the stainless suddenly cracks open.
This is one reason why the stock manifolds w/precats have bolt on reflective heat shields rather then wrapping, yet the stock y-pipe uses a wrap and metal covering. The exhaust cools significantly by the time it gets down to the y-pipe and wrapping is not an issue.
I wouldn't wrap my headers anyway but would design or copy the heat shielding if it was important.

Mild steel advantages are that it is cheaper, ductile and therefore less likely to crack.
Mild steel disadvantage is the higher thermal conductivity (in this case) and its inability to resist degradation from the high heat of the exhaust due to the diffusivity of the carbon and other alloying elements. This heat affects any metal but it is slower and requires even higher temperatures in the desirable stainless steels. This is exactly why 304L or better is good for the higher temp "hot" pipes and 304 is good for the cooler sections. I don't know if the weaponR headers are 304 or 304L but I'd really like to find out.

Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black