Here are a variety of reasons to coat an exhust manifold header.
Corrosion Protection: The manifold will live longer as well as look nicer. Whether it is for performance or show, coating as exhust manifold is valuable to you.
Thermal Barrier: The coating is a thermal barrier, thus keeping heat within the manifold or header.
Benefits: Firt by keeping heat within the manifold, you are goung to accelerate the exhust velocity, which reduces back pressure and reduces fuel contaminiation due to reversion. This is a performance benefit.
Reduce Drag: The first is benefit is that fact that you reduce drag. For a gear to turn in a heavier fluid takes more power. The lighter the fluid, the less power is lost simply to turn gears in this fluid.
Greater Cooling Capability: The second benefit is the fact that a lighter fluid has grwater capability to cool the part from the heat that is generated by friction. A lighter weight fluid will carry that heat easier and transfer it to the case more readily than a heavier gear lube.
Coating an Intake Manifold
Peformance: In this instance, You are dealing with heat that is generated by the engine. You will also aquire heat from the hot oil that may be tossed up under the underside of the intake manifold. This means we want to apply a thermal barrier (BC2, CBX, MCX) to the bottom of the intake manifold, the flange area where it would bolt to the head, and also the flange area where the carburator would bolt to the intake manifold. This will reduce the amount of heat that enters the manifold itself, keeping the manifold cooler.
One of the best apllications for coatings is in combustion chamber areas. Coating the combustion chamber of a cylinder head can increase performance significantly. In additon, more compression can be run, as the proper coating can provide resistance to detonation.
Some more benefits can include; Keeping heat in the thermal barrier, Moving heat over the surface to reduce hot spots, reflect heat onto 'cooler' or shrouded areas of the chamber, The coating retains less residual heat from combustion that other thermal barriers, thus transferring less heat to the incomikng fuel charge.