The first thing that really stands out when looking at the stock air filter, is the almost shocking thickness. Measuring a whopping 3 inches thick and made from a pleated paper filtering topped off with a thin (about 1/4" inch) layer of gauze, it's no wonder optimal airflow just isn't there with the OE filter.
In contrast, the AFE intake filter itself is of course conical in shape, allowing for a bigger surface area. It also isn't nearly so thick, approximately 1/4 to 3/8 of an inch, and the pleats are more open than on the original VW filter. AFE offers multiple filter material choices, both oiled and dry. We went with their Pro Guard 7 oiled filter. Here's what the filter looks like.
And here's what the filter would look like installed.
With high filtration rates (high 98% for the 5 layer oiled cotton Pro 5 R filter, 99.2% for the 2 layer synthetic oil-free Pro Dry S, and 99.7% for the Pro Guard 7), and up to a 56% increase in airflow, it stands to reason that AFE cold air intakes will deliver power and fuel economy gains. In our next post, we'll take another trip back to Ely Nevada. With this 2.0L VW TDI intake installed we hope to see some kind of fuel economy gain.
Just one quick note; the addition of the AFE intake made a noticeable difference in reducing turbo lag off the line. The car just drives better, both at lower speeds, and on the freeway. Throttle response is improved, and the car is already more fun to drive!
For all your VW TDI performance needs, shop Parleys Diesel Performance.