I believe the potential compressor stall problem can occur if all (hot and
cold) sonic nozzles are plugged.  It would "seem" than plugging the hot
nozzles would be "ok" as long as you don't set the mixer to hot (which then
also plugs the cold ones).  

My (limited) understanding is that the std TCM TSIO-550E Turbo system is
designed to need the sonic leakage (either hot or cold).  The waste gate
controller is not responsive enough (and/or the typical exhaust back
pressure too high and/or the turbo momentum too great) and without the
leakage, the inflow can become too slow for the rapidly spinning compressor
blades, which increases their effective AOA, and they stall (similar to a
wing with high AOA).

My understanding is perhaps overly simplified (and/or potentially
wrong/confused).  Would love to be set straight if so.

Rick


-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
billhogarty

...Also, I was not aware of a possible compressor problem if the hot air
outlets were blocked.  Maybe the ADA folks could clarify.