Exhaust flange - Engineering Design Challenge for you Audifans tinkerers

[SJ]

From: "Huw Powell" <audi at humanspeakers.com>
To: "SJ" <syljay at optonline.net>

> > My 88 5kq, non turbo needs a 4 hole mounting flange on the end of the
> > downpipe for connecting the downpipe to the Cat. The flange needs an
inside
> > bevel to match the flared donut that sits between flange and cat.
>
> Why not get a dead cat and cut the flange off that to work with?
**** Lot of work. The inside ID might not match the pipe. Yah, I just
measured it . .Pipe is 2.35 and ID of cat flange is 2.180
Hard to get a dead cat . .the cars at the junkyard sit on axles. Cant get
underneath the car. And, I dont have your ready supply of "parts cars" in
the backyard.

> I guess it does need to "split" somehow to get onto the downpipe, that
> could be two cuts and welds, if you're handy.
**** Yup, cut flange in two and use a backup plate . . .all shown in
diagrams on the website.

> Or, a used downpipe from force5?
**** Money can always "buy" a solution. We need to 'invent' something . .
.and for cheap!
Besides, the flange on an old downpipe will be just as rusted to hell as
mine is.

> I know at one point I cut off a 4 bolt flange from a 20v cat to put it
> on my 89 90Q, I must have welded on a 3 bolter.  I have no memory of
> what I did, however.
**** You already having senior moments like me?
I aint got no welder. Life would be easy with a welder.

> This brings up another option, which is to use a readily available 3
> bolt split flange and obtain a "scrap" 3 hole piece to weld to the cat..
**** I was looking at that. I have a new 3 hole split flange in hand. The
problem with these flanges is that they rust to hell in about a year. I want
to go stainless. You got me hooked on this stainless stuff . .its all your
fault!!!!

> As far as simply "making" a new one from scratch, you don't mention what
> machining equipment you have, or is allowed to be used (and believe me,
> if you have to pay to get "one" of these made, you could buy a new
> downpipe for the money).
**** I wasnt thinking of making a new flange, but buying one ready made.
Then modifying it slightly.
I have a sawzall and a drill press. That should be enough equipment if I can
get a manufactured flange with the right dimensions.
I'm sourcing a likely place in Canada for the flange. This guy builds
stainless exhausts for audis and bmw's and custom jobs. He mentioned $15 CDN
for a stainless 4 hole flange. I'm working this angle.
He said that if he was doing the job, he would cut off the flared end of the
downpipe, slip on the new flange, and weld back the flared end of pipe.
Again . . .the welder, which I dont have.

SJ