It is in a permit Falco.
I currently have the red set at 400 and the yellow at 380 with a view to always staying in the green but my fuel flow figures are rather high (35 @ 23 × 23) and I’m beginning to wonder if I don’t have a cooling issue. I do not have matched injectors. I do have leaky baffles which I am currently in the process of rectifying.
Every time I research this subject I find yet another article which draws yet another different conclusion from the engine operator’s manual.
As Mike Busch hints at here, not only the type of engine but also its installation plays a role in determining a CHT target. He suggests 380F for most planes, but 350 for an SR22:
http://www.avweb.com/news/savvyaviator/savvy_aviator_59_egt_cht_and_leaning-198162-1.html
Ultimately, you would have to run very extensive tests on your installation until you have enough data to determine the optimal value. Until then, I would err on the cold side.
So what type of plane is this engine in?
If the aircraft is non certified, obviously the red and yellow lines for CHT are your choice. FWIW my choice would be red line at a number above which the manufacturer says engine damage will likely occur, in a relatively short period. Yellow for me would be the number above which I believe longer term operation impacts engine or component life, maybe 380 or 390 F. Then I’d use the yellow line as an operational limit. Just one point of view.
So, a concensus of two say 400 for red bur we have a disagreement on the yellow. Any other contributions?
Come to think of it, may be EGT should be RED when at or near nil reading. 
Bah. Who cares about cylinders. They are consumables. Fedex delivers overnight and we all have a mechanic friend who changes them for free.
Obviously you are taking the p1ss.
Bah. Who cares about cylinders. They are consumables. Fedex delivers overnight and we all have a mechanic friend who changes them for free.
Absolute EGT is meaningless. I would not be able to connect a colour range to any EGT reading.
Remember, it’s not a real constant temperature reading but an averaged indication of the combustion cycle. For example, increasing RPM will increase EGT reading. However, the gases are not hotter in the cylinder.
As CHT’s are a constant reading, here a colour range can work.
It is generally accepted these days that 380F is the point to do something to reduce temps.
400F is a no go area.
Of course engine manufacturer’s limiting max temps are much higher.
CHT Yellow: 360F
Red: 400F
The values in the engine manual are much too high if you want your cylinders to survive until TBO. I think Mike Busch wondered if that was because engine manufacturers want to sell engines and replacement parts.
Stickandrudderman wrote:
please don’t say, “the ones in the POH” because there isn’t one!
Well, there is a manual for the engine, isn’t there?
