hi all, right i got myself a pipercross filter today from awsome , which bit of the air box do i smooth, the top bit is it? if so do i have to remove all the re enforcemant ribs and will this weaken the filter box lid

It's the bottom of the air filter box you have to smooth out.All the fins etc...

dont bother mate it made no difference when i did mine

Alot of elbow grease, and work, for .... no difference.

It made an audible difference when I did it (and replaced the standard filter with a Green one). Couldn't tell you if it made any other difference though.

It definitely makes a difference on a remapped car. Myself and a friend with a Mk4 Golf 1.8T did lots of airflow logs comparing induction kits and the standard airbox in various states with different filters, cold air feeds etc.. The standard airbox smoothed, fitted with a green airfilter and a 80mm cold feed pipe gave significant increases in airflow both in peak figures and throughout the rev range.

It's ever so easy to do, as well. Score along the fins at the point where they join with the box with a chisel or something sharp, then use pliers to snap them off. Provided you got your scoring right, that leaves an almost imperceptible ridge, which a little more work with the chisel (carefully) and a bit of sanding if you're feeling energetic, will remove in a few minutes. The whole job takes 20 minutes or so.

It's ever so easy to do, as well. Score along the fins at the point where they join with the box with a chisel or something sharp, then use pliers to snap them off. Provided you got your scoring right, that leaves an almost imperceptible ridge, which a little more work with the chisel (carefully) and a bit of sanding if you're feeling energetic, will remove in a few minutes. The whole job takes 20 minutes or so.

Yep, I used a good stanley knife and pliers. It all comes out very quickly and the box is still strong enough to lean on when working under the bonnet.

i used a cutting attachment on a soldering iron to do mine as i couldnt find a sharp enough knife to score the fins but yea mine too about 20/30 mins to do

righto looks easy enough there's only a couple of fins and i have a dremmel might as well do it

cheers for the info dude's

I'm not a "dude" but you're welcome :P

I'm not a "dude" but you're welcome :P

Youngsters these days, eh pops?

I'm not a "dude" but you're welcome :P

Aww come on dude relax

It's the bottom of the air filter box you have to smooth out.All the fins etc...

Hang on i always thought it was the top of the filter box

Hang on i always thought it was the top of the filter box

It is...well actually all of it.

I only did the top i beteer get back out there lol

I only did the top i beteer get back out there lol

Looking at the design I reckon the top has the biggest effect.

Looking at the design I reckon the top has the biggest effect.

i think it was on your advice that i only did the top lol

right i'll do the lot this weekend then, anyone put in an extra cold air feed look's like there's some spare space to put a 2" tube in the bottom of the box top left corner only problem i can see with fitting is that it might foul the gear linkage ,has any one done this and were did you route the tube

cheers dude's , chap's and gentlemen

I replaced the existing feed with an 80mm duct routed to the lower passenger side bumper grille.