Read the following article from popular mechanics. The magazine tests a very similar product. In theory it works, but because of all the complex valves in today's modern engines, it does not work. In fact, some tests proved it decreases gas mileage because it restricts air flow.

http://www.popularmechanics.com/auto...32.html?page=2

__________________
Michael

2008 BMW X5 3.0si
Space Gray/Black Nevada Leather/Bamboo Wood Trim
Premium | Cold Weather | Technology | Automatic Tailgate | Comfort Seats | iPod Adapter

Previous:
2004 BMW 330xi