"O. Sami Saydjari" wrote in message
...
My per-cyclinder avg EGTs are as follows:

#1: 1370
#2: 1390
#3: 1450
#4: 1450
#5: 1480
#6: 1430

The difference is 110 degrees between the coldest and hotest cylinder.
A colleague of mine says that is a bit high for a fuel-injected system.
Is that right?

He suggest rotating the injectors from the hotest cylinders to the
coldest ones to try to better balance them (so, for example, swapping #5
and #1). I am not sure why one would do that. Have others done that
with success?


Not legal. That's the reason GAMI had to spend a lot of time and money
getting an STC.

http://www.avweb.com/news/reviews/182558-1.html


"Once Braly understood the reason for the mixture maldistribution, the
solution was obvious: vary the orifices in the injector nozzles to
compensate for the "borrowing" of fuel between cylinders. The lean-running
rear cylinders need larger-orifice injectors that deliver a bit more fuel,
while the rich-running front cylinders need smaller-orifice injectors that
deliver a bit less.
Of course, George wasn't the first to come up with this idea. Knowledgeable
A&Ps had been quietly playing "musical injectors" on their big-bore TCM
engines for years. I say "quietly" because the use of different-sized
injectors on a TCM engine wasn't exactly legal: the engine's type
certificate data sheet specifies that all injectors are to be the same size.
So this is the sort of thing that mechanics would usually do only on their
own airplanes, and it usually wouldn't show up in the logbooks or be spoken
of in public. Generally, this injector swapping was done on a hit-or-miss
basis without engineering discipline or instrumentation. Sometimes it
worked, sometimes not."