3" Cottons Downpipe- ext gate


Nov 15, 2011
I just got this and not sure if it's mild steel or stainless. The flanges/welds have surface rust but the pipe doesn't. Is there any way to tell?
Try the magnet test? Sticks = mild. no stick = stainless. What wastegate is it? If it's the 2-bolt flange for a 38 turbonetics/tial it will be mild. We had a limited production for the turbonetics v-band rg-45 in mild. Most of the downpipes for precision v-band pw46 were stainless.
I don't think any flanges on dps are stainless.
Not to confuse the situation, but thinking back we did make 1 or 2 stainless 2-bolt wastegate flange downpipes. If you have it, it's worth atleast twice as much:D
This is the DP.


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hello boys; There is SS that will atrack a magnet. It depends on the pull of the magnet. If it grabs with force it's mild steel but if the grab is slight it's SS.
The TA headers I got does that and when I got them coated the pull explanation was told.