Question abou cobb stage 1 tune

[Ganjie]

I am currently running a stage 1 cobb tune on a 2017 fiesta st. I current mod list Includes: ram air filter, awr motor mount set, and turbosmart Kompact and atmospheric.. I noticed the other day that when accelerating my afr drops to 11. Seems a little lean to me. Is this normal? Located in NJ

 

[FiestaSTdude]

Mine does that on a regular basis when I give it the beans.

 

[sonicmn]

I am currently running a stage 1 cobb tune on a 2017 fiesta st. I current mod list Includes: ram air filter, awr motor mount set, and turbosmart Kompact and atmospheric.. I noticed the other day that when accelerating my afr drops to 11. Seems a little lean to me. Is this normal? Located in NJ

Just for clarification, I'm not throwing shade at your question as I think its good to learn!

I think 11 is more on the rich side of the spectrum (safer) 14:1 would be stoich and on the lean/dangerous side... learning from my buddy that builds/tunes hotrods, I believe he usually aims for 12:1 under load with boost.

All of this could be wrong, so any corrections are welcome... Y'all are awesome