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

[Ken Keith]

On 28 Nov 2001, at 11:02, Swann, Benjamin R.  (BSWANN) wrote:
>
> 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.

Are you going custom on the single pass IC, or using the stock version?

Which Garrett are you using?

> 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.

I'd be very wary of cutting it in half and welding it back together.  I
believe some have had success welding cracks in the manifolds, but
even this is rare.  Often it cracks again, and this is just a crack in an
otherwise good manifold.  Cutting it in two and rewelding would seem
even more difficult.

> 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.

I haven't heard too much about it being a bottleneck, I always hear
reference to the catalytic convertor.  I'm sure eventually it will be the
bottleneck in the system at some point, but on a stock setup I'm not
sure that it is.  This is based on past posts to this list by others, and
not from my own personal experience.

Budgetwise, I would have to say that there really is no alternative to the
single piece factory manifold.  See below.

> 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.

The two-piece is about $850 for the collection of parts from the dealer,
with the q-list discount (from Carlsen).  I posted some info to the list
about this recently.

I heard that the two-piece actually does flow a little better, in particular I
think it was to the 5th cylinder, where the shape of the new/two-piece
manifold is very different (more direct) than on the old/single-piece one.

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

Me neither.  There's a lot of temptations and opportunities to do that
however, at least that's been my experience with my '88 5kcstq.  The
"right" way (usually a factory or aftermarket upgrade) is always way
more expensive than homebrewed fixes.

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

There is an aftermarket log-style manifold from Dialynx that has a
horrible reputation.  Phil Payne throws them away for scrap in the UK,
and some U.S. listers have tried them and took them off.  Others run
them without too much problems.

The main complaint about them is that they warp and pull studs out of
the head.  Perhaps this happens once, after which it can be resurfaced
and reinstalled.  Some experience multiple warping episodes.  One
lister described the problem as saying something to the effect of, "The
damn thing is alive and it will twist and pull until it breaks free of the
motor once again."  That wasn't the exact wording, but the point comes
across.

Other problems with that manifold are that it is difficult to install, with no
axial access to some of the nuts, and other fitment problems.

The design itself is less desireable from a flow perspective than either of
the stock units, IMO, since it is a log-type of manifold insead of
employing separate runners for each cylinders gases.

The Dialynx retails in the U.S. for about $795, but can be had cheaper if
you look around and/or buy used or from Dialynx themselves.

I was leaning towards getting a Dialynx and cryo treating it and
machining it, but I was convinced otherwise.

Later,

Ken