On Fri, 24 Apr 1998 12:09:28 EDT JMerz140 <JMerz140@aol.com> writes:
>Since the two SUs are connected to a common manifold that can
>mixtures of each, how does this effect the color you see on the
>can see how the use of two Colortune units might be far more accurate
>just one. Any comments or thoughts along these lines? Jim '53 TD
Although the carbs are on a common manifold and there is a LARGE tube
between the two, they do not "crossfeed" between the sides of the
The purpose of the balance tube is to just that, balance the vacuum
signals between the intake runners, and for a convienent place to hang
the various vacuum operated components such as gulp valves, brake booster
connection, etc, etc.
The tube is such a length that the inertia of any charge (fuel/air mix)
in the tube will simply move partially from one end to the other as the
intake pulses. About the time it begins to move in one direction, it gets
a vacuum signal from the other end and has to stop and reverse direction.
In fact, the "air" near the center of the balance tube is relativly
If the two carbs were "interconnected" as it were, shutting off the fuel
to one or the other would have no effect on the low RPM performance of
the car as one carb is more than suffecient to handle the engine demands
of the engine. And we all know what happens when one carb goes south; you
can't even get the thing to idle right.
While dealing primarily with the "A" series engine, Vizard's book gives
a really good analysis of the trials and tribulations of the MOWOG twin
carb manifold, and the vast majority of the thesis is directly applicable
to the "B" series engine.