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Subject:More Exhaust System for I-4 Comments
From:Frank Grunthaner
Date:Tue, 4 Jan 2000 10:41:03 EST

In reply to R. Feuerriegel's comments, I have no photographs to post as of
yet. I planned to document the conversion, but I'm constantly tinkering and
the months go by. Some other details on the exhaust system. The exhaust
manifold I used is the "large flange" dual downport manifold offset towards
the transmission. This manifold clears the diesel motor mount. This manifold
when used in the A1 series has a substantial bellows flex assembly between
the manifold and the exhaust pipe flange. For space reasons, I decided not to
use this because the radius of curvature for the initial pipe bends would be
too tight for the diameter of tubing we used. As I recall, we used 1.75 inch
tube but it could be 1.5. Getting old too fast. Anyway, I matched the ID of
the exhaust tube to the ID of the holes in the flange and gasket. We then
snaked these dual pipes around to the rear drivers side with the smoothest
mandrel bends we could use to join to a two to one 2.5 inch collector. This
was welded to a generic cat (thought about the two inlet cat with one outlet
but the total length of that RV cat was too much) and that to the big Durango
muffler (still 2.5 inch diameter) then welded on the 18 inch resonator.
Finally, a 90 degree tip is welded on ending right at the edge of the body
side plane. The system is suspended at two points: the exit of the cat and
the exit of the resonator. The system sounds remarkably like a Porsche 944
Turbo without the resonator, but she-who-must-be-obeyed suggested that
quietude was the long term (trip) objective.

BTW I now have $350 total in the system including my part of the experiments
supported (so to speak) by Dynamax and my muffler shop.

Frank Grunthaner