For many years, pilots and mechanics with a good understanding of
the operation of internal combustion engines have known that the
fuel/air distribution in our aircraft piston engines has been less than
optimal. With the invention of multi-cylinder engine monitors, many
pilots started watching an unsettling graphic display of just how far
from "optimal" or "uniform" the cylinders were running in their engines.
During a normal lean cycle, such as most pilots routinely perform
just after arriving at their crusing altitude, pilots with engine
monitors have discovered that the EGT's on the various cylinders will
all reach peak at greatly different total engine fuel flows. At cruise
power settings, GAMI engineers have seen some engines in which the first
cylinder reached peak EGT at, for example, 15 GPH, and the last
cylinder did not reach peak until the engine had been leaned to a fuel
flow of 13 GPH or less. This "spread" in fuel flows, from the first
cylinder to reach peak EGT until the last cylinder to reach peak EGT, is
a sure indication of just how unbalanced the fuel/air ratios are
between the various cylinders.
Notice in the discussion above, that the important issue is when
in the complete lean cycle each cylinder reaches peak EGT, not the
absolute value of any particular EGT. Many pilots make the mistake of
focusing on the absolute temperature of the individual cylinder's EGT,
rather than focusing on the sequential timing when the different
cylinders reach their maximum exhaust gas temperature.
STC'd, PMA'd and fully legal.
GAMI has developed and certified specifications for a set of
precision fuel injectors for almost all engines in the current
Continental and Lycoming fleet of fuel injected engines. We have STCs
and PMAs on over 300 different engine models.
These specifications are optimized for each engine model, based
on the extensive testing with GAMI's state-of-the-art 96 channel data
acquisition system. Data, not "hangar talk"!Article about the GAMIjectors by an Aviation site: AV Web article