IMCO Inlet Air Temperature Regulation

Fig.7 - IMCO Inlet Air Temperature Regulation:

This system is designed to maintain the temperature of air entering the carburetor at 100° F (75° F on some applications). This temperature allows for improved warm-up characteristics, minimized carburetor icing, and leaner carburetor calibrations. Fig. 7.

The main component parts of this system are: an exhaust manifold shroud, a vacuum operated duct & valve assembly, a duct tube, an air cleaner bi-metallic beat sensor, and on some applications, a fresh air intake (zip tube).

Intake air is routed past the exhaust manifold and preheated in this manner until a predetermined temperature is reached. At this point, the heat sensor controlled valve closes off the duct tube and allows the engine compartment air (or outside air on zip tube equipped vehicles) to enter the air cleaner. This process repeats itself while the engine is running at a constant speed, and maintains the temperature of intake air at about 100° F or 75° F.

During acceleration, decreased intake manifold vacuum allows the vacuum motor on the duct to relax, and full air flow from outside or engine compartment can reach the air cleaner. Some applications use an auxiliary air inlet valve to perform this function.