Cold Air Kit

Dan the man said

When installing a cold air kit, I understand that it's best to mount the air filter outside of the engine compartment, but with the air duct still being in the engine compartment wouldn't it be a good idea to insulate this as it's exposed to the heat of the engine compartment? Seems to me that even though the filter would be picking up cooler air that it would be almost as hot as if the filter was still under the hood.

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I installed this on my '68 Barracuda. It sources the cooler air from the high pressure zone at the cowl. I had too much stuff in the way to route it to the grill area, so I used the cowl to access cooler air. It did feel like it increased performance, but my previous air filter set-up was probably a restriction in and of itself.

If you've ever opened one or both of the fresh air vents and felt the blast air into the footwell area in these cars while doing freeway speeds, you can understand why engineers have used the cowl as a source for outside the engine compartment for cooler air.

The middle of the hood is a low pressure source to grab cooler air at speed. I remember reading somewhere that a hood scoop would have to be around 2 feet tall to position the opening into higher pressure air. The airflow that is displaced by the front of the car flows up above most hood scoops and then crashes down on the cowl before being forced upwards again by the windshield.

Regardless, the air is often significantly cooler from a low hood scoop than engine compartment air.