[Gmecm] AF ratio 14.6 is stoich?

[Sjödin Robert]

I was reading a book and found an AF-ratio table. The 92-98 RON petrol was listed as stoich at AFR 14.6. My $8D calibration is set to 14.7. The window where the cat conv is operating is about 14.5-14.6 (according to same book as above) so why is it 14.7 in the code? Seems a little off for keeping the emissions low...

Using WBO2 I see that my engine is a little lean (lambda 1.02-1.05), should I reduce it to 14.6 or is it perhaps that my idle SA is little off? My engine will pass all sniffer tests but I would like to increase the margin a little, my HC is little high (60-80 ppm).

Thanks Rob