Withstanding Peak Temperatures

Ron Rosenfeld wrote in
:

Is there a limit on EGT? I've never seen an explicit one, but I've
only operated normally aspirated engines. Are there TIT limits?

There are TIT limits -- IIRC around 1650°F I don't know what the
limit is on the Lycoming valves.

In my TN Lyc IO360, I've never seen the TIT above about 1500°F. But
in fully turbocharged engines, the TIT limit can be exceeded.

There are limits, depending upon the material used to construct the
exhaust system. It's usually in the 1550 F to 1650 F range. [I want to
say that the Iconel system is TCM and good for 1650, but please don't
take my word for it.]

The problem is that EGT probes are VERY subject to error, and it is hard
to truly measure the temperatures accurately. The probes themselves are
very accurate, but the tiniest changes in placement, or even
positioning, can make a significant difference in reading. That's why
we tend not to look TOO CLOSELY at absolute EGT readings, and to want
some "margin" between what is allowed and what is read.

For instance, my TSIO-360-FB allows temps up to 1650. I try to keep
them below 1550 in cruise, however, and only VERY seldom let them go
anywhere near 1600 even in hot/heavy climb.

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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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