Not always true. Another benefit of a cold air intake is the reduction of air restriction. When the cylinder pulls in air, that takes work. The less restriction in the air intake, the less work your engine has to do. In addition, you get "more efficient combustion" because the cold, dense air will aid in the burning of the air/fuel mixture. Of course, if you delve into your extra power, you'll probably lose miles per gallon. It's all up to how you drive.ps- If you actually read into it, I would love to check out your sources.
