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Re: 10v turbo exhaust manifold
> b) If they flow better than stock Audi, I would be surprised. The
> casting is _much_ simpler - the Audi stock design divides the airflow
> into three channels to the turbo, combining two pairs of cylinders
> into two channels to create a sustained scavenging gasflow. The lip
> to the port is also the same size as the port - in the Audi manifold
> it's slightly larger, again to promote scavenging.
Looking at the design, I would also be surprised if the Dialynx manifold
flowed better than the "two-piece" manifold. That said, I was a little
disappointed with the poor quality of port-matching of my manifold ... and
the head for that matter. In both cases, compared to the EM gasket, the port
was shifted about 2mm to the front of the engine ... fortunately, since I was
opening up the port, I was able to put everything back pretty much where it
belonged and managed to get an approx. 30% increase in flow at full lift
(10-12% just off the seat and 18-20% at .250"). BTW, the majority of the
exhaust flow is along the port roof, not the floor, and because of this,
conventional wisdom has it that the anti-reversionary lip is only necessary
at the bottom of the port. We'll see when I get the motor together...
> The Audi replacement is actually 7-piece, I think. Make sure they ship
> you a blanking bolt for the measurement hole - they don't do this by
Blanking bolt? Measuring hole? Are you referring to the boss where the
sniffer port attaches for emissions testing?