EGT Accuracy

"O. Sami Saydjari" wrote in news:105d6vadm8klu68
@corp.supernews.com:

What is the accuracy of the average EGT gauge?

GAMI did some checking on this early on... using NSTI calibrated
equipment for comparison. A modern GEM or JPI gauge should be accurate
to within about a degree or so... fantastically accurate for such
equipment (assuming it's not just plain broken).

However (!!) placement of the EGT probe is so sensitive that the actual
readings you get are pretty much arbitrary. As long as all of them are
placed identically, you will get very accurate readings AT THAT POINT,
but it's really more of a "comparison" thing than an exact specific
number.

My PA-28R-201T POH says that temperatures of 1650 degrees are
"allowable." My EGT's never get above 1420 even at the absolute peak.
Does that mean I am "golden" as far as temperatures go?

Well, first off, 1650 is NOT a temperature you want to operate at! It
just means that if you don't go above that then most of the metal in
your exhaust and turbo will only have gotten soft, not actually melted.
{:)

EGT's of 1400 - 1520 are a nice range. [Your TIT can read almost 100 F
above the EGT, although I seldom see that.] I'm a bit surprised you
never see anything higher... sounds like you are running very rich.
What do you usually use for cruise? And what are the corresponding temps
and fuel flow?

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James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
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