Guys,

I have a question on something that I noticed in the off-the-shelf TBE 93 octane fuel map. The fuel map is leaned out at low loads and low rpms. I have highlighted the area in question. This is the area that my Xede fuel map traces while I am cruising. Why would this area be leaned out if during cruising your are in closed loop and the car operates at stoich 14.7:1? What is the purpose of leaning the AFR in this area?