I am flying a Lancair Legacy with an IO-550  10:1 compression -
Performance engine that has been inspected and rebuilt about 60 hrs
ago.   I have had a problem, which I attributed to new cylinder/rings,
with excessive oil consumption.  Initially I was using about a qt an
hour and this improved at about 15 hrs.  Seemed like normal break in.
Then one flight back from the  coast of OR (Sea Level - I fly out of
Bend  - 3500 ft), I started losing oil pressure.  When I landed after
the hour flight I had about 5 qts left.  I started with 9.  I
attributed it to a crazy idea I had to hook the breather tube into the
exhaust.  I was getting really tired of cleaning the bottom of the
plane and my hangar floor.   I disconnected it and flew and problem
solved.  Just recently on a trip back East the same thing happened.
Got to Rawlings, Wy 8.5 qts running grat no problems.  Next stop about
1.5 hrs, 2 added qts.  On my way to Kansas City oil pressure dropping
slowly so I diverted and now I was down to 4-5 qts.  After spending
the night in Kansas city and buying a case of oil, I flew back to
Bend.  Used 1/2 qt in 6 hrs.

So a few things.  I have a 12 qt oil pan, I have an air/oil separator,
I checked my crank pressure by hooking a pressure gauge to the
breather (before the separator) and it is high somewhere in the 4-5
psi.  I did a compression check and.

OK so why intermittently dumping from the oil breather?