I have used a SCOM on my 18 RXP for three years. With 210 pound rider, full fuel, 700 MSL and with 85 degree air, it ran 74-75 at 8060/70 rpm. That is slightly above the rev limiter, but with the electronic I Control limiter rather than a chip, I have never felt it slow the engine and it will hold that rpm.

I watched the Greg Gaddis video on SCOM results with his 21 RXP and he saw 77 mph. I wanted to see what my results would be on my 21 PX, so I moved the SCOM to the new machine. He is much lighter than me and his fuel level was about 1/2 tank. With full fuel, my 21 PX showed a sustained 75 with short bursts of 76. The tach was showing either 8000 or 8100. It no longer displays in smaller increments than 100.

What I observed that I had never seen before with a SCOM was that the engine management system (rev limiter) was actually coming into play and slowing the engine down. I could definitely hear and feel the engine slow and the tach return to 8000. It was not as dramatic as the GPS speed limiter, but I could feel it.

I'm not sure how Greg got his to run 77 without getting pulled back by the I Control, but mine won't run a sustained speed above 75 due to the rev limiter. In my case, using a Maptuner to raise the rev limiter and no tune will get you at least 1 or 2 mph over a SCOM. I was expecting them to be equal, on the 21 hull, they are not.