The sonic nozzle is a device to restrict the flow of air drawn from the engine compressor output to a certain number of pounds of air per second. The standing shock wave in the nozzle limits the flow when the flow gets fast enough to form a shock wave. That said you should be looking a a convergent divergent interior to the nozzle. It narrows down more abruptly on the inlet side and more gradually on the outlet side. If it opens up you can have unacceptable flow separation and more noise and efficiency loss. Look for more gradual slope in the nozzle and that is the outlet side.
Re: Sonic Venturi Orientation on TSIO-550
Posted for "F. Barry Knotts" <bknotts@buckeye-express.com>:
Lancairian engine persons...I have a question. (Several, actually.)
I acquired a 7 year old, never run, Continental TSIO-550 that had been
prepared by Lancair with the complete firewall forward fastbuild treatment.