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Best location for cool air in engine bay

Experiment done by Rick

I measured the temp at various potential cone filter locations. 3 measurements were made consecutively over 4 runs with the engine warm. I first let the temp reach equilibrium while idling (1), next I accelerated to 45 mph and made a measurement after 1/3 mile (2). Then I speed up and cruised at 55 for 1.5 miles and made the final measurement (3) - the temp had pretty much stabilized at that point. The results are as follows (degrees F). At the throttle body (151/118/90), under the battery tray (97/91/82) at the stock air box (165/100/82) and at the stock intake (75/64/62).

My conclusions are that there is significant outside air flow into the engine at speed, reducing the under the hood temp. There is more air flow at the stock air filter location than at the throttle body. The clear winner was under the battery tray. There are no high heat sources under or nearby and there are no obstructions to the outside air. The last measurement was made at the current air intake at the front of the engine compartment. Due to the draw of outside air from the vacuum from the engine, the temp there was significantly lower then at an other location. Therefore, in positioning a cone filter, one must consider the length and heat sources in the path to the source of fresh air. Remember, for every increase in charge temp of 20*F there is a approx 1 percent decrease in HP.


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