Heatshield Products Heatshield Armor exhaust insulation is one of the most effective, efficient thermal barrier materials on the market. Its specially formulated BioCool material reduces the amount of heat an exhaust pipe radiates up to 70 percent. That heat is kept in the pipe/exhaust system, helping to improve exhaust system performance through increased exhaust gas temperatures (EGT) and exhaust gas velocities. But we’re often asked why it’s necessary to leave a gap when installing Heatshield Armor on exhaust pipes and not fully wrap/insulate the exhaust pipe?

Installing Exhaust Insulation Does the Following:

• Reduces radiated exhaust heat and heat exposure under-vehicle components are subjected to

• Improves exhaust gas scavenging from engine cylinders for improved engine performance through increased exhaust gas temperatures and velocities

• Helps lower vehicle interior temperatures by reducing floorpan exposure to radiated exhaust heat

Because it is so efficient at keeping more heat in the exhaust system, if you were to fully insulate and exhaust pipe with Heatshield Armor, it would contain so much extra heat most exhaust pipes would surpass the thermal limit of their steel alloy. This causes the pipe to start degrading and rusting, eventually ending in failure with the pipe basically dissolving into a powder of rust particles. This is why you often see cheap exhaust headers and exhaust pipes start rusting and coming apart after a short time because the steel alloy they’re made from doesn’t have a high enough heat rating to withstand the extra heat exhaust insulation contains in the pipe.

ABOVE: Because of Heatshield Armor exhaust insulation’s efficiency cutting up to 70% of radiated heat from exhaust pipes, it’s important to leave a gap between the ends of the insulation during installation so the exhaust pipe has just enough uninsulated area to “breathe” and dissipate a small amount of heat so the pipe doesn’t exceed the maximum sustained temperature rating of the pipe’s steel alloy.

Not fully wrapping an exhaust pipe or header in Heatshield Armor exhaust insulation, leaving a gap between the ends of material allows the pipe to “breathe” and dissipate a small amount of heat. While the insulation still significantly reduces the radiated heat coming from the exhaust pipe, the small amount the gap lets out helps to keep the exhaust pipe from getting too hot and surpassing its maximum sustained temperature rating.

ABOVE: Like an exhaust pipe, a muffler can’t be fully wrapped in exhaust insulation to prevent overheating and damage. Besides the steel alloy the muffler is made from, the acoustic packing material used inside a muffler can’t be heated past its maximum sustained temperature either. Heatshield Products Muffler Armor kit is designed to insulate the muffler just enough to reduce radiated heat but not cause the muffler and internals to surpass their maximum heat rating.

When it comes to mufflers and catalytic converters, our Muffler Armor kit that uses Heatshield Armor insulation the same rule applies to why the entire muffler or converter isn’t fully wrapped. Besides the steel alloy the muffler is made from, there is the other part involving the acoustic filler material used in most mufflers, and that material’s maximum heat rating.

ABOVE: Catalytic converters are a major under-vehicle radiated heat source. They too can be partially insulated/heat shielded to reduce radiated heat, but a portion must be left uninsulated so the converter doesn’t overheat and melt its internals to cause converter failure. The important thing to keep in mind when installing Heatshield Armor exhaust insulation and the required gap, is placing the material so the heat release gap is directed downward or away from the components or area you want to reduce heat exposure to.