I heard wrapping headers plainly in that heat tape/wrap will rust out headers.If you ceramic coat the headers and then wrap them,will the heat be lowered even more than just the ceramic coating alone or is it now defeating the purpose?--yes i know ceramic coating is for heat dissapation also but will you get twice the heat reduction if you use both the coating and the wrap?
Coating headers on the exterior will reduce heat, but is mostly for rust reduction - and when headers rust on the inside, they can lose efficiency and horsepower. Ceramic coating really belongs on the inside to maintain flow, not the outside, and is a race modification that's not really understood. In this case, the value of headers can be completely negated in less than 20,000 miles just from interior rust creating as much backpressure as a stock manifold. Header wrap is used by some in racing to minutely increase horsepower - on the street, it doesn't deliver enough to justify the expense. Dyno estimates run less than 10 hp on a highly tuned motor, street motors would show 1/3 the improvement. Wrapping them to reduce underhood heat and hot soaking other components can be simplified by just adding a heat shield to the starter, or adding reflective insulation to the firewall or floorboards - which will also reduce interior noise and give better results. Header wrap will increase rusting of all headers - but if they are ceramic coated on the outside, it won't show as much. All in all, header wrap is a very specific race item that is a negative for the street, as are most race car modifications.
The ceramic coating prevents the heat from being transmitted from the inside out through the header. The heat wrap prevents the heat coming out of the header from effecting other things in the engine compartment, ie plug wires, etc. You wont get twice the heat protection because the ceramic is much more effective then the wrap. The reason the headers rust out is because water gets between the headers and the wrap, turns to steam, and has nowhere to go. Anything, even stainless, will rust if you leave it in water long enough. Id say if you want to wrap something, wrap the plug wires and leave the headers as they are.
