smoothing the airbox

90jb11

Registered User
hi whats this smoothing the airbox all about what does it do and is there a tutorial about it?
thanks
 

Westy

Registered User
If you have a look though my progress thread (link in my sig) you'll see my pics and the logs I did. You basically remove all the ridges from inside the box and sand it as smooth as you can. This means that there won't be as much resistance in the box for the air to pass over. I got an extra 3bhp and 7lbft from doing it on my S3.
 

Westy

Registered User
i just have a 1.8 no turbo will it be as effective?

I dont think it will but it will be interesting to see what gains you get, if any. It also made my throttle response a bit quicker.
 

90jb11

Registered User
cheers mate think i will give it a go is it a quick and easy job or can it be a *****?
 

Westy

Registered User
cheers mate think i will give it a go is it a quick and easy job or can it be a *****?

It takes a while to do.

The easiest way I found was to use an extremely sharp stanley knife to score the bottom of each plastic fin then use a pair of pliers to snap the fin off. This will leave you will some tiny little lips to sand down. If you have a dremmel and a sanding pad it's a lot quicker to do.
 

Dane

Had an 8L S3, a B5 RS4 now I have a B8 S4
It's not a particularly quick job but it's easy for sure/ What he said
 

90jb11

Registered User
thanks alot mate will do that at weekend and i have a debur air tool at work that will take the pips of so that should be easy
 

Westy

Registered User
thanks alot mate will do that at weekend and i have a debur air tool at work that will take the pips of so that should be easy

Go easy on the sanding in the middle of the bottom part of the box as it's quite thin by the moulded circle bit (you'll see what I mean) and it's quite easy to go through the box.
 

kwistof

South East Events Moderator
I'm also looking to do this on my S3 in prep for the Vortex cone from the GB.
How easy is it to take the airbox out? Is it just a few screws to undo?
 

Westy

Registered User
I'm also looking to do this on my S3 in prep for the Vortex cone from the GB.
How easy is it to take the airbox out? Is it just a few screws to undo?

I think you mean Jetex. There will be no point smoothing the airbox for the cone as you will need to hack the airbox up to get the cone to fit.
 

kwistof

South East Events Moderator
Yep, I definetly meant Jetex! lol. Dunno where vortex came from :s

I may find a donor airbox to practice with before hand then.
 

Westy

Registered User
If you have a look in Tuffty's build thread you'll see how he cut the box to fit the cone in. It's a fair bit of hassle but if you want it to look OE under the bonnet then it's a good thing to do.
 
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