I noticed this the other day, at about 90kt.
You can get quite high EGTs even at a very low power setting. Normally this doesn’t matter but at low speeds the exhaust is not getting much airflow, and this could become a factor.
Or perhaps a high EGT at a low power setting does not translate to the same exhaust system temperature as the same EGT at a high power setting, due to different internal gas mass flow.
It would be interesting to instrument an exhaust system one day…
Interesting. Are you sure your timing is correct? Did you try to switch off one mag and check the diff between L/R/both?
Is this value at peak or ROP/LOP?
Did you had gear down and full flaps?
Interesting. Are you sure your timing is correct?
Yes.
Did you try to switch off one mag and check the diff between L/R/both?
No. However I have done high altitude mag checks a number of times. Never saw an anomaly.
Is this value at peak or ROP/LOP?
It would have been the enroute setting (peak EGT) followed by a low power descent.
I will do some testing next time I go up. Set up a low power descent and try different mixtures.
Peter wrote:
a high EGT at a low power setting does not translate to the same exhaust system temperature as the same EGT at a high power setting, due to different internal gas mass flow
Of course, heat transfer is not only dependant on temps but also mass flow, you are not going to hurt anything thermally at 45% power at peak EGT on lycosaurus engines. You can hurt some other things as you well know, due to vibration spectrum, low RPM, or too low ICP (internal cylinder pressure)
High EGTs do not represent a threat to engine longevity. The engine is simply not capable of producing EGTs that are high enough to harm anything. Therefore, attempting to limit EGTs in an attempt to be kind to the engine is simply wrongheaded.
Limiting CHTs is essential to ensure cylinder longevity.
Limiting EGTs accomplishes nothing useful.
The above is a copy-paste from https://resources.savvyaviation.com/understanding-cht-and-egt-2/
A high RPM should give relatively high EGTs since the combustion hardly has the time to complete before the exhaust valve opens. I wonder if that reading on the picture was with a high RPM. EGTs should decrease with a lower RPM, giving combusted gases time to cool before hitting the EGT sensors.
