Peter wrote:
You should start leaning long before that –
I was reading the AFM for the C182T (normally aspirated) the other day, and to my big surprise they are still advocating not to touch the red knob below 5000 feet and lean during climb only if the engine runs rough at full rich, despite being equipped with individual EGT and CHT for each cylinder.
Well, that will work, of course, too 
You will probably burn another 2-3 USG reaching the operating ceiling (maybe FL170 for a C182), and will get some “interesting moments” in the higher altitudes when the engine starts to run “rough” above the Alps
But, as I say, it will work.
I don’t think these manufacturers can ever change their POHs because if they did it would trigger claims that the previous version was incorrect.
It would be interesting to establish what makes Michael’s plane do the extra speed, which is worth quite a lot of extra HP. Laminar surfaces help (at a cost of making the aircraft unusable in any icing) and it’s probably a lot cleaner; the TB20 has a huge number of pop rivets which cannot be helping.
On request from someone and following the Bonanza posts here I did a test today.
I get 153kt IAS at 13.3 USG/hr.
Conditions: 3000ft (+7C) or 5000ft (+3C), QNH 1028, 24"/2400rpm, peak EGT.
At 11.5 USG/hr I get the usual 140kt IAS at both 3000 and 5000ft. This is the normal low level cruise.
IAS?
