As Mark has noted, the manifolds (single downpipe) for the longitudinal
engines are all very similar. The major differences are in the bosses or drilled
holes for the O2 sensor and the exhaust gas test port, with about 1 to 2 mm.
I.D. difference in the exhaust port hole diameter. The 3A is the largest, and the
flow is greatest here for the single hole units. All of these flow better
than the G/J TD units as I have said and are more than adequate for the diesel
application. I use the test port or the O2 sensor poprt for the start for a EGT
sensor mount for a diesel application. BTW, the simple flow test bench I use
is a take-off of those described at the Autospeed electronic magazine site (a
place I highly recommend for those addicted to the technical thrills of this
hobby (!).

Frank Grunthaner

In a message dated 4/25/05 4:51:12 AM, jfarrugi@UMICH.EDU writes:

> Frank
>
> did you flow one of these manifolds that Mark speaks of in your manifold
> testing?
>
> jonathan
>
> On Sun, 24 Apr 2005, Mark Drillock wrote:
>
> > The 4 cylinder longitudinal mount engines from Audi and VW used a very
> > similar manifold to the Audi 80/90 4 cyl manifold that Frank speaks of.
> > The Audi 4000, VW Quantum, and VW Fox till 1990 all used the same one.
> > These have the same bolt pattern, flange, and gasket as the Audi 3A
> > engine manifold Frank worked with.
> >
> > Mark
> >
> > FRANKGRUN@AOL.COM wrote:
> >
> > >.....
> > >
> > >
> > >>3. How common are these 3A manifolds? Do you have have any for sale?
> > >>
> > >>
> > >>
> > >The 3A single port manifold is very similar to the FOX manifold. They
> should
> > >be everywhere. I could sell some of the excess stock, and photograph the
> > >installation, but with conferences, fiels trips and instrument builds, I
> can't
> > >settle in the garage until the end of June.
>