> Marc...so then, which header tubes do you suggest putting probes for an EGT
> gauge?
>
> Craig Carter
If you are going to run two probes, I say run 2 and 3. That way you'll get the
leanest cylinders (at least most likely to be lean in most cases) from each carb
(especially useful on dual SUs and less significant on dual Mikuni/Webers). If
you are going to run only one probe, I say the center cylinder that is fed by
the carb furthest downstream from the fuel pump. The reasoning being that if the
carbs are daisy chained (i.e. fuel line feeds one carb and then the next, rather
than feeding a distribution block that then feeds both carbs ), the last carb in
the chain, i.e. the one furthest downstream from the pump, is the one most
likely to starve for fuel and run lean. And the center cylinder, or leading
cylinder, (2 or 3) is the one most likely to run lean due to firing
order/manifold design. By monitoring the leading cylinder of the carb most
likely to lean out, you are more likely to catch a lean out condition if one
arises. If you can run two dual egt gauges and four probes, you will know the
situation for all cylinders at any given time. You will also be considerably
poorer. :-) A cylinder running a bit rich will not cost you $$, OTOH a lean
running cylinder almost always will.
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