Hi,

I've just got hold of a pipercross panel filter and when i've searched, people mention de-finning the airbox.

Now i'm sure when i open the airbox this will become obvious, but does anyone have any pics of what their's looks like just so i know before getting the dremel out!!!

Cheers

Here's a picture of one with the fins removed, but you can see where they were

Don't bother with a Dremel, get a chisel or something similar, and score along the join between the fin and the box. Then get some pliers and bend the fins, and they'll snap off very easily. You can clean up the remainder with a chisel or with the Dremel.

what are the benefits?

what are the benefits?

i presume the air can flow more easily.

what were the fins there for in the first place? they must serve some purpose?

Edited 26 January, 201016 yr by Jonners_GTI

i presume the air can flow more easily.

what were the fins there for in the first place? they must serve some purpose?

For strength I'd presume. To stop the airbox from collapsing when exposed to a vacuum, or just to make it more sturdy.

Or they may serve some aerodynamic, acoustic or basic filtration purpose........

Who knows! We need to ask the VAG engineer that designed it!

I don't know for sure but one or more of:-

1) Making the plastic flow better in the injection moulding machine.

2) Additional strength.

3) Helping to silence the intake.

4) Physical support for the underside of the stock filter.

Could it be to make the air coming into the box more turbulent, thus creating a vortex type induction.

Sounds impressive but probably no truth in it at all.

Since the filter box is far from being an ideal shape, chances are the fins act as baffles to equalise the suction across the entire top surface of the filter. Otherwise, there would be preferential flow along the path of least resistance, so filtration would be less efficient. You'd still get as much air into the engine, but as there would be a higher dP across the filter in the preferential flow zone, you'd be drawing in more particulate. Probably not a big deal taking the fins off in the UK, but during rush-hour in Beijing or a sandstorm in Riyadh, it could be a serious issue...