Chat:

< why do you run LOP?>

Because the internal cylinder pressures are lower, the CHT's are lower and the engine runs  cleaner.  The oil stays cleaner longer.  As Carl Goulet, former VP of engineering at TCM said, " Cleaner is better. Cooler is better. LOP is cleaner and cooler."  Also, the most efficient mixture setting is about 40dF LOP (on average).  I like being fuel efficient.  At low power settings, the BSFC(min) is at about 15-20dF LOP.  At very high power settings, the BSFC(min) moves out to about 70-90dF LOP.  I can run the engine at very high powers LOP that I cannot attain ROP without placing very high stresses on the engine. Basically, that's why.  I've been running all of the engines I fly LOP since 1996.  Why?  Well, I've seen what happens to them when they are ROP on the engine test stand.  I don't want to do those things to my engine, and I don't want to go slower, burning more fuel.

<Does this apply to all engines or just turbo?>

All spark ignition, gasoline, piston engines--NA or TC'd, injected or carbureted.

<What is the optimum temp past LOP?>

That depends on the power setting used.  The higher the power setting, the further LOP you should set the mixture.  By as low as 60% power you can set the mixture anywhere you want without fear of harming anything.

 <Hope these questions don't open up a can of worms,>

What the heck, I'm used to it!  <vbg>

Walter