re. porting 2-pc EM, and other mods - 5000 Turbo Quattro

[Swann, Benjamin R. (BSWANN)]

QuattroPhile,

I have a similar situation as what Ken is enquiring about below.

I will be pulling off the stock manifold on '87 Turbo Quattro Wagon for R&R
of gaskets/slight leak.  While I'm at it, I plan to perform other upgrades
and modifications for additional fuel and flow, including camshaft, Garrett
turbo, single pass IC, extra fuelinjector/controller, etc.

I have an extra stock manifold to play with, and was going to "hog" them out
a best as possible.  I was actually contemplating cutting the thing in two
to access and enlarge, then weld back together.  Putting doubt on my welding
skills, however, I have reservations about welding the cast iron manifold.
I do have MIG and/or Carbon arc welders available, but have never done this
kind of extensive welding with cast iron.

Is this a sane path to go down, or is there some sensible (budget wise)
alternative to the stock manifold?  My understanding is that the stock
manifold will be a bottle neck and at bare minimum I should do some porting.

What kind of cost are we talking about for the two piece.  My understaning
is that the two piece doesn't gain much flow or reliability over the stock
manifold, and it is not cheap.

I don't want to be penny-wise and dollar foolish however.

Is there a decent header for the 10V MC-1 or other alternative?

Whose BTDT?

Ben
'87 5Kcstq Avant (x2) - taking pearl to the next stage over chip and
wastegate spring.
'85 4kcsq - project GTQ on hold.  Modified NG engine on garage floor since
it is wifes car, and I have not been able to break the original motor.

[Hello Audifans,

I've got a 2-pc exhaust manifold on the way, and I was wondering if I
should tweak it before it put it on.

I'm not very concerned about cracking or warpage with this unit, so I'm
not thinking I'll spend money on having it cryo treated.  I suppose I could
go this way too, since now will be the chance, and it supposedly
increases the strength and stability of the part.

I think ceramic/JetHot coating might be a good idea.  I live in central AZ,
where it gets hot in the summer.  Underhood temps are going to need to
be controlled, and I think it's better for peformance to keep the heat in.

What about porting, or modifying the shape of the internal fins at the
end where the turbo bolts on?  I believe there is a piece of "webbing" or
a wall between two passages that abruptly comes to an end at the
flange.  I seem to recall someone sharpened that edge to make the flow
smoother.

I don't want to eliminate any potential anti-reversion lips by match
porting it.  I guess since this is receiving gas from the head, then there's
no way to decrease the anti-reversion lips by messing with the EM.

Should I bother going through it and smoothing things out?  I imagine
there might be some casting flash or something.

Basically, I'm wondering what the drawbacks or negatives to trying this
are?  A concern might be that by removing material, I might make it
weaker or more susceptible to cracking or something.

Thanks,

Ken]