Engine Exhaust Coating Comparison

Posted by Alex Darmos on

By Joe DeMonte 
Senior Thermography Course Instructor 
Infrared Training Center (itc) 
ASNT/PdM TIR Lvl III

Historically speaking, reducing engine bay component temperatures has been critical in achieving success for many types of automotive racing. The cooler that some of these components are during operation of the vehicle, the more efficient the engine becomes. Colder air coming into the engine also equals more power when compared to the same volume of air at a higher temperature. Manufacturers and race teams alike try to reduce the heat gains to incoming air with several techniques. This paper will discuss a couple of those techniques and utilize a state of the art infrared camera to visualize and measure the effectiveness of changing the heat transfer capabilities of exhaust components.

Modern engines with fuel injection and electronic computer controls have become increasingly complex and more efficient with each engineering advancement. Smaller displacement engines can now offer excellent gas mileage along with unheard of power and performance. In this test, we decided to use the car that we currently race at IHRA and NHRA drag strips across the east. Our test car is a 98 Buick Regal GS with a supercharged 3.8 liter fuel injected front wheel drive engine. The engine came stock with heat reducing radiant barriers on the exhaust components. This was a sign to me that heat reduction is carefully considered by the manufacturer during design on new vehicles.

How can you take a good product and make it better for performance and racing? It can be a challenge given the level of care and thought put into today’s cars. To start, we decided that in order to take advantage of increased air flow and pressures caused by our aftermarket supercharger changes, we would need to open up the stock exhaust system to handle the exiting gases. Our exhaust is composed of 5 basic parts that provide safe transfer of the exhaust gases to the rear of the car. These components also provide a quieting effect and reduce the harmful emissions of the engine that would make their way to the atmosphere.