I'm citing a couple of Nissan techs and Technosquare who claim that the G becomes too rich in the upper RPM range. According to Technosquare and these techs, it operates on the rich side of the power curve particularly approaching red line. Those are my sources, for what they are worth. I don't claim to know the truth but I do trust Q45 and Technosquare. Other than that, I just wanted to comment that there is a lean side of peak, a rich side of peak and an actual optimal point of peak power that one tries to achieve when optimizing HP. Also, more rich and more lean can both make the combustion area cooler although too lean can cause pre-detonation.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

Neff,
Just to clarify, I was only speculating what this device did, and mainly wanted to drop a note about the rich/lean power curve. I'm sure how the S-AFC II operates, but to know for sure how it's benefits are delivered, we first need to know for sure where the G operates in that air fuel power curve. If it's operating "rich of optimal power" then it must be running it more lean. If it's operating "lean of optimal power" then it must be running it more rich, as you've hypothesized. I'd love to find out. If this device has safe air/fuel merits, I'll be first in line! ....after my plenum, cats, headers, exhaust and pulley that is .

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way