[Mark540]

Cooler air is worth about 1 hp per every 10 degrees drop as a rule of thumb on the average NA motor, as zoomy says about 1% hp increase at 60 mph from ram air, but only if you put the inlet in a high pressure area. The major increase in any cold are intake is in the design, which allows more air in the engine(less restrictive) my 99 vette pic'd up about 12 rwhp with a cold air intake, which is common on the vettes based on the very restrictive factory intake design and element. Since it was on a dyno there was no ram air effect. As stated before this is a big topic on almost all FI car forums.

Mark