Originally Posted by graniteguy
Cold air intakes are something I have always wondered about. On most dyno's the hood is up and a large fan is blowing air across the truck. To me, this would give an exaggerated gain with the intakes because of the fresh supply of cold air. A heatshield becomes irrelevant in that situation, but close the hood and it does. This method of calculating may bring the truth out on some advertised gains for these things because it IS real world.
Heres some results from Digimoto run over a 3 day period.
The outside air temps were 68 degrees, 71 degrees and on the 3rd day.. 70 degrees.
First day was a stock airbox modded and a K&N drop in air filter. Silencer was removed. IAT measured 2-3degrees over outside air temp.
Second day was a K&N. 2-3 degrees hotter..
Third day.. MAC .. 2-3 degrees hotter..
I ran said test due to someone complaining about MAC's making the air hotter because their metal.. the air moves so quickly through that 16inch tube theres no time to really effect the IAT readings nor the air temp.
To stay on topic, any mechanical drag on an engine will reduce its power output.. any pully, pump, belt.. By removing any mass from said chain, the engine will gaine something.. how much it gains.. it will vary.