smoothed air box


Registered User
Sep 5, 2007
Reaction score
Reading a lot ov peeps have done this

whats the point ov it

any pics
The theory is a smoothed airbox will flow air better, theoretically it sounds good but on a forced induction (turbocharged) engine the air is being sucked in so hard by the turbo it going to get the air it needs anyway as long as it isnt too restrictive.

On an NA engine it would probably yield better results as the air needs to be sucked into the engine on each piston downward pre-firing stroke, this is why they use cams on an NA more than on turbocharged cars as the air is forced in by the turbo anyway so you dont need to work as hard to get it in, where cams keep the valves open longer or with more lift for more open area to allow the amount of air needed to be sucked in.

I am going to do mine though every little helps as they say and I bet that plastic weighs a few grams :drag:!
As it happens TDi 110bhp remapped, but i smoothes mine the other day going on what i heard i had spare time so spent a few hours doing it all... Did take a few hours as said to do it proper and very fiddly but seems to have make a difference!!! After removing all the plastic in the way i ran sandpaper over it didnt go to town just got it quite smooth didnt 1500 it just got fine sandpaper... But yer as said seems to have worked a bit for me...

BUT seriously its painstaking wouldn't wanna do it again lol !!!
I did as I had nothing better to do on a Sat afternoon LOL and I found it made a slight difference for me... Smoother pickup overall when it's a cold day....
Agree with fran, did mine the other week and car just felt smoother and picked up that ever so slightly better, for what it costs (nothing) and the time it takes (30mins tops) you might aswell do it.
i did it last weekend, took all of 30 mins using a small angle grinder and some sand paper.... drilled couple of sm,all drain holes etc....

it makes a tiny whoosh when i boot it but would put any gains down to the placebo effect...that said it doesnt mean there isnt a benefit there... i just cant really tell

Similar threads