Jeff,
Unfortunately, the plane met its end before I measured things. The last props I ran were a 16x6 and 16x7 APC. 16x6 gave very good vertical, but would go supersonic very easily in the air. 16x7 gave good, but not great vertical, and did not go supersonic, but it also speed the Quest up more than I'd like. Maybe a 17x5 or 6 would have been better? This was with a ST 90, wraparound header, Mac's Quiet pipe, 15% Mach7/Morgans fuel, with a Perry pump. I used the header at stock length directly into the pipe. Worked well, and JUST fit in the Quest without lengthening the tunnel. By the way, this is an old ST 90 SK, not the G, but they are basically the same.
Hope this helps.
Jon Lowe
ORIGINAL: Jeff-RCU
Jon,
I'm building a Zafiro and have a new ST90 and thinking of doing the same thing you did (wrap around header and a mac pipe, it would all fit in fuse of a Zafiro). What kind of prop and RPM's were you getting from your piped set up?
Jeff