Peter wrote:
a turbo engine must last less long simply because it is running at 100% power for the whole climb
I need 100% power only for take off and initial climb, setting is 32 MP, 2500 RPM, FF 24 GpH, say for two minutes only.
Then I reduce the setting to 25 MP, 2400 RPM, 16 GpH according to the data in my POH, I think the power is reduced to 75% but not exactly sure about.
This works without difficulties up to any altitude. When reaching cruise level I reduce the MP to 23, the RPM to 2100-2200 which correlates with a FF of 11 GpH, 60% power.
TIT never exceeds 1630 which is 50 rich of peak, CIT an Oil temp. are well in the green arc, of course one need to use the cowl flaps.
There are no metal particles in the oil filter, the spark plugs have a typical brown colour and the leak test is perfect. I take any effort to protect the engine like Engine dehumifier and CAMGUARD. The engine has now 800 hours total time and I hope to reach 2000 hours as minimum engine life time. What else can I do?
The GAMI/TAT course teaches that an RPM reduction after t/o slightly increases the internal cylinder pressure and is therefore worse on the engine than remaining at max RPM (except for noise abatement). They have the data.
I climb at full power and at high IAS (125-130 KIAS) for CHT cooling (IO-520 TN). Continental CHTs should be managed below 400 F, nowhere near the 460 POH limit. EGTs are irrelevent as long as they are below the limit (1650 F for me) and I’m suitably lean of peak in the cruise (70 to 80 LoP for 83% power).
Martin wrote:
I personally think temperature is the key to long life.
Yes, Cylinder Head Temperature. Whereas EGT does not matter much – it can be argued that EGT is not even a meaningful property other than for reference.
But what about TIT? While I believe there is plenty of evidence that being conservative about keeping the CHT below yellow line with a large margin is good for the engine, is there any penalty for running the TIT close to the limits?
huv wrote:
is there any penalty for running the TIT close to the limits?
Apart from frying the turbo? 
No. If your TIT limit is 1650 you can run at 1649 all day.
No. If your TIT limit is 1650 you can run at 1649 all day
There must however be a long term impact on the exhaust life if, like most, it is made from stainless steel rather than inconel.
Exhaust repairs are a frequently reported very pricey item at or before overhaul time.
I recall hearing of exhaust costs of 5k to 10k… A top overhaul is about 10k.
This is one reason why when someone asks me about TBs I tell them to get the GT. Inconel exhaust.
To paraphrase Georges Braly (Founder of GAMI) :
“It’s not how hard you run your engine, it’s HOW you run it hard that counts "
I would agree 100% with that statement and would add that “babying” the engine is not particularly good for it.
Peter wrote:
There must however be a long term impact on the exhaust life
Is this a case of worrying when you know and blissfully ignoring when you don’t? Non-torbo’ed engines have no TIT and so really no indication of the exhaust pipe temperature (unless you believe that EGT in absolute numbers has any meaning). In turbo’ed engines, the exhaust turbine in itself will actually reduce temperature due to pressure drop (although I have no idea how much).
chrisparker wrote:
No. If your TIT limit is 1650 you can run at 1649 all day.
Michael wrote:
“babying” the engine is not particularly good for it
Any details of that? Apart from the engine break-in, is there any harm in “babying” the engine if the oil and cylinder temps are within recommended margins?
