wrote:
Are you talking about a specific installation in a specific airplane ?
The red line for my TIT is 1750ºF. 1350ºF is way cold on my airplane.. I
don't think I could possibly put that much fuel through it.

I believe recommended on the turbo Arrow is 1650F. [I could be off on
that, but that's memory.] Some systems do allow 1750 - but they have a
different metal for the exhaust.

For the problem itself - first off, as was said, make sure the fuel
system is set up correctly. You should be over 20 gph on takeoff
power. For cruise, do you have the cowling cooling mod? [I'm guessing
yours is an Arrow III.] That's the set of side vents (one on each
side) that were added. Most older turbo Arrows have had them added by
now, but not all.

The Merlyn Automatic Wastegate is a popular mod for that aircraft.
It's not a true automatic controller, but it is a durn site better than
the screw-in bolt that Piper installed. Having said that, the main
heat advantage it gives is down low. Up high it allows more power
(much more), but doesn't help with heat (with one exception below).
Some folks have installed an intercooler, but it really shouldn't be
necessary.

Now for that exception: If you *really* want the temps to come down,
reduce engine RPM. I cruise about 2300 or so, no more than that
certainly, at any altitude. However, without the Merlyn, you may have
trouble getting adequate power up into the flight levels.

Another option - run LOP. Then you can pretty much put the temps
wherever you want them. Again, though, with the fixed wastegate at
high altitude, you may not be able to produce the power you want.

And lastly, the most absolutely obvious (that is frequently
overlooked). Have your engine baffle system looked at by someone who
knows what he is doing. Very small leaks can make a huge difference.