re: Modifying the exhaust on 80's Spider

[Godfrey DiGiorgi <ramarren@domain.elided>]

Be careful here. The header/downpipe & catcon of the '76-'81 Spiders is
terrible: poor shape, poor flow and prone to cracking (mine did, and four
other people reported the same thing happening to theirs when I mentioned
it ages ago). These bits are one of the main reasons I wanted to move to
an '82 or later powertrain ... the stock '82 and up exhaust header and
catcon are FAR better than the earlier catcon equipped exhausts from the
late '70s. They also lack the fitting for the Bosch injection system's
oxygen sensor so that would have to be added in additionally. 

Other solutions I've heard people talk about are all similar: use a pre-76
exhaust header and have a custom, high-flow rate catcon fitted along with
the oxygen sensor receptacle, or do the same thing with one of the good
competition headers. Working out the details of the exhaust fitment are
always fussy when you're mixing system and years: although most pieces
look like they ought to be identical, making them fit without banging the
chassis, etc, is often challenging. 

For what it's worth: Based upon what I've learned and what I've been told
by several folks intimately familiar with Alfa engine development, unless
you're going for a very radical engine which won't pass emissions testing
in any state anyway, you'd be best off sticking with the stock exhaust
system pieces. They fit perfectly, they last, and at least after '82 they
are only minimally restrictive if at all given the rest of the engine's
state of tune. If it's power you're after, the first areas to be addressed
are the compression and the cams ... bring your engine up to 10.4:1 and
then put in some slightly more aggressive cams and you'll wake it up
nicely. I've done the first part so far - high compression pistons - and
a set of cams is on the "to be done" list for the future. :)

Godfrey

>I was told a while back that it is possible to replace the
>one-piece catalytic converter/exhaust pipe with those from an
>older 70's Alfa that would have the bolt-on type cat.  In this
>case I would be replacing the whole assembly with three pieces,
>one from the headers to the cat, the cat itself, and one from the
>cat to the muffler.  Does anyone know which Alfa model would be a
>good fit?

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