Being a newly designed engine there isn't much out there about about the limitations of the factory pistons
I have noticed that factory is 10.5 at times and the base maps are using 11.2. Running 11.2-11.5 would have been my guess for safe running A/F under load. Is 11.2 conservative? Does anyone have any knowledge of the construction of the OEM Si pistons?
Safe Air/Fuel ratios
Re: Safe Air/Fuel ratios
The factory ECU runs 14.7:1 under boost. I would not worry about the AFR as far as the piston goes, but it is more of a concern for knock control.
Hondata
Re: Safe Air/Fuel ratios
Very good information to know. Sounds a bit more like a Diesel piston than gasoline. Makes sense considering the intense cylinder pressures in these tiny engines.