Modify ABY airbox to ADU spec?

[Henka]

So, RS2 airboxes are not easy to find. After analyzing this whole problem, I've come to believe that the biggest gain is in the lower part. Sure, the top should make some difference, but that one is not as easy to modify.

Isn't it just a matter of cutting a bigger inlet hole, more centerd as it is on the ADU and then "just" find and fit an airhorn/inlet pipe to fit the hole. Oh, and also, modify the shield behind the light assy.

As fo an airhorn - do you think I could use a subwoofer taperd port? I mean the kind that usually is found on subwooferboxes (open woofers). Don't know what it's called though.

As fo the top part... Is the difference enough to motivate reconstruction of the top? I mean, how much diff will it make??

[Greg_S]

The difficult part is getting the trumpet the right size and length inside the box since this is quite critical fromwhat i understand

[Rusty]

I brought some modular subwoofer ports a couple of years ago for about £30 each. They're bell-mouthed so would be perfect for the job. They come in three sections with the centre being 3" diameter and you cut it to length. Gives all the equations for working out tuning frequencies for the length of the port. I assume that the length is important as the longer the port, the more more resistance to flow but the shorter the port the more turbulence in the air stream enterring the air box. I also assume that the MAF prefers a more linear flow to ensure that it measures more accurately the amount of air going through it, therefore, excessive turbulence is not good. I could, of course, be making an **** of myself though!

[Tommy200rs]

Henka,

check theese in a shop near you :-)

http://www.biltema.se/products/product.asp?iItemId=78643

http://www.biltema.se/products/product.asp?iItemId=78649

110mm 155-285 mm Produkt 31-470
110mm 150 mm 31-475

[Audi Parts Guru]

Henka,

Just buy an RS2 airbox, It's much easier as there are quite a few differences between ABY and ADU airboxes

[Henka]

Pja...

Henka,

Just buy an RS2 airbox, It's much easier as there are quite a few differences between ABY and ADU airboxes

Easier? Well, yes if new, no if used. As much fun? nope. Quite a few differences? Yes, on the upper part mainly. Main item? Snorkel/funnel/airhorn. Easy to copy since my buddy has a RS2? Yes. More fun to try and make one myself? Yup.

And about the frequency and length of airhorn. Well, I'm not that sure that it really matters all that much. It's probably tuned to cut out certain frequencys, to keep down intake noise. Yes, it will add to flow but since it's a turbo and it's coupled to a lon rubber pipe on the otherside of the MAF...well I don't know. Guess I'll have to calculate the frequenzy it's tuned for and the check out the RS2 box and compare that. That way, I'll be able to tune my lower section in the same fashion. Wonder if it's the same as with intake runners - longer gives more bottom.

[Audi Parts Guru]

I just bought a used one for £50, fitted it in about an hour

[HPmuirt]

I just bought a used one for £50, fitted it in about an hour

Where the hell did you find it and does it have a twin brother ?

I have been looking for one for ****** months

Cheers n

Si

[Audi Parts Guru]

Where the hell did you find it and does it have a twin brother ?

I have been looking for one for ****** months

Cheers n

Si

I bought it of a guy who posted on here just after the S2 forum started, think it was about 2 years ago. Put my K&N filter in and off I went