Rick writes: <<<<Likewise, it seems obvious that a compressor with a smaller A (outlet area) would generally flow a smaller volume and/or create/sustain a higher pressure ratio (other things equal and with other performance spec impacts) relative to a similar compressor with a larger A.  However, I've never fully understood “why” Radius and A/R ratio (with Area held constant as shown below and assumed in our installations) has much effect on compressor performance (apparently based on some other articles I've read, it doesn’t).  >>>>>

My understanding is that the compressor nozzle is not the compressor discharge, it is the axial gap in the housing at the circumference of the impeller. Flow leaving the nozzle then expands radially, slows and recovers pressure.

A set of compressor maps for the T04 with the 0.5 and 0.6 A/R compressors would tell us what changes what.

Regards
Brent Regan