Black or silver............a clean nitrous tune WILL discolor them at the first bend and make them dingy right there. It's GONNA happen, don't care who coats them, or what color they are
Monte... whats the EGT on a good tune
You can't tune a gas motor by EGT numbers. It's just a number. I only use them to see if all the holes are lit. I have cars that run anywhere from 1200-1600 and everywhere in between.
As to coating holding up on a nitrous car, depends on who coats them. Before we went to stainless headers, Nitro-plate did ours and they held up VERY well. The bends would get dingy in one pass, but overall it held up well. Kind of like a piston coating on a nitrous car. There isn't one made I can't burn off, except for hard anodizing.......LOL!!!
