968Forums.com

the link died - here is the article from 9 Magazine, and the DIY for the airbox flow modification that dave greimann and i worked out



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As these cars continue to change hands, I am sure this will benefit some new owners.

Where has that article been hiding? never seen it. Printing and adding it to the binder.



Thanx

lol - sorry - i just today realized that it got buried - this was a while ago that we worked this out, so it sort of got forgotten

968 engineering no longer has the rings for the airbox mod.

Should I bother trying to get/make rings, or just cut the holes? Do the rings have function other than making the mod look more professional?

Nice to see the original article, it makes interesting reading.



I had problems finding trim rings in the uk, but eventually found some 2" bass tubes which did the job.

I expect there are plenty of options in the US and I'm sure that there are plenty on the site who can help.

i htink i need to merge a couple of threads here



yes, the trim rings make a difference - the right design (bell mouth or at least round) helps smooth airflow - the wrong design (square edges) creates turbulence - no rings creates turbulence



turbulence in this case does not mean it still won't be better - it just means a little less efficiency, and a less pleasant sound

OK..I'm a believer now...and mod soon to come..

I was reading this interesting mod. Seems like something even I can do.

Question is where can I get those trim rings needed to optimize airflow into the box?

seems like the website referenced is not online any longer

I am not sure, but RS Barn may have them.
Worth a shot, Pete is a great help.

crutchfield

the company that used to carry them and where 968 engineering got them (parts express) stopped carrying the right kind

If you check out hifi or car stereo suppliers you'll probably be able to find trim rings (used in speakers).

yup - just make sure you get ones for which you can get a hole saw the right size, and ones that have rounded entry edge profiles - the idea is to smooth the airflow going in, not make a square corner which disrupts the airflow

i've gone even farther, and have plans to do more - it's helping

I just gotten confirmation from Pete at RSbarn that he has them in stock and I am ordering them from Pete.

Thanks for the heads up

When I did the airbox mod I use ABS pipe coupler (21/2" to 2") from home depot for my ports - pictures are on page 9 of the thread listed below - for me it has worked out well - since then I have got the front engine cover so you don't see them at all...

Sam



http://www.968forums.com/index.php?showtop...4&hl=airbox

those are pretty bumpy - i am quite sure that the flow is broken up there - it's all about the bell shape, and smooth entry, essentially trying to mimic a velocity stack - square edges disrupt airflow - a contoured edge facilitates it - the more the contour, the more it helps

might be a minimal advantage in this application, but velocity stacks work - i know there is a difference between the square edge and a rounded one - you can actually hear it

<!--quoteo(post=78740:date=Aug 26 2009, 09:07 AM:name=EEZATOY)-->QUOTE (EEZATOY @ Aug 26 2009, 09:07 AM) <{POST_SNAPBACK}><!--quotec-->When I did the airbox mod I use ABS pipe coupler (21/2" to 2") from home depot for my ports - pictures are on page 9 of the thread listed below - for me it has worked out well - since then I have got the front engine cover so you don't see them at all...

Sam



http://www.968forums.com/index.php?showtop...4&hl=airbox<!--QuoteEnd--><!--QuoteEEnd-->

+1 on the ABS pipe coupler. I then used my flex shaft (commercial sized dremel) to reshape the leading edge to a pseudo-velocity stack.

<!--quoteo(post=78738:date=Aug 26 2009, 11:09 AM:name=johns_968)-->QUOTE (johns_968 @ Aug 26 2009, 11:09 AM) <{POST_SNAPBACK}><!--quotec-->I just gotten confirmation from Pete at RSbarn that he has them in stock and I am ordering them from Pete.

Thanks for the heads up<!--QuoteEnd--><!--QuoteEEnd-->
[img]style_emoticons/<#EMO_DIR#>/cool.gif[/img]

Flash,

The edges inside the coupling is actually angled (45 degree) where it goes from the 2 1/2" to 2" - so no real square edges - no to say that there isn't some air flow disruption from it not being a straight shoot, but its a readialy avaible and cheap option...

ah - looked like right angles from the pic - that's definitely better