What AFR-values are generally considered as lean/spot-on/rich?
Is the spot on value the same throughout the RPM-range?

 

It will vary from car to car but around 11.8 to 11.2 and may be a bit richer wot full load to keep plug and cyl temps down in effort to stop det.

It also worth pointing out that running slightly rich flat out will only loose you a few bhp, but will result in a "safer" tune.

Subarus like mixture on the rich side as apposed to some other turbo cars that can run mixture as lean as 12.2 wot.

Jase.

 

Sorry just re-read your post, Idle afr is around 14.7 cruise can be as lean as 15.2 for economy above post was for max load and wide open throttle.

Jase.