A vehicle's exhaust system is designed to quickly move exhaust gases (created through the combustion process) from the engine to the tail pipe. Combustion gases can exceed 1000 degrees Fahrenheit and contribute more to engine heat buildup than heat produced through friction of the engine's moving parts. Use of an exhaust wrap insulates the exhaust system. Exhaust wraps typically are installed on the exhaust manifold or headers, and can also be used to wrap temperature sensitive materials (such as plastic coated electrical lines) to protect them from heat exposure.
Engine compartment temperature is raised as a result of the hot exhaust components. Wrapping the exhaust components reduces the overall temperature of the air in the engine compartment.
Wrapped exhaust manifolds reduce heat transfer to the intake manifolds. The engine operates more efficiently when the intake air is cooler. When the engine's intake manifolds are subjected to the heat produced by the exhaust system, the intake manifold transfers the heat to the intake air, reducing engine efficiency.
Electrical components exposed to the high temperatures of hot metal can melt and short. Wrapping electrical components in exhaust wrap insulates the electrical lines from heat and reduces the possibility of failure.
Air intake systems draw the external air through an air filter, through an intake tube and into the throttle body. The air filter box and intake tube are heated by the air temperature in the engine compartment. Reducing the air temperature in the intake compartment results in cooler air being injected into the engine, which increases the engine's efficiency (and overall horsepower produced).
High temperature exhaust gases have lower density than low temperature exhaust gases. By insulating the exhaust system, the higher temperatures are maintained, which in turn lower the density of the exhaust gas. Lower density exhaust gases travel through the exhaust system faster.
Small changes in operating temperatures can extend the life of the engine and engine components. Insulated exhaust systems reduce the amount of heat transferred back to the engine.
Hot engine compartments can heat the hood to temperatures, which may damage or alter custom paint jobs. For vehicles with high performance engines (including turbo systems), reduction of engine compartment temperatures can help prevent hood and hood paint deterioration.
