Afr after IVC

Does the statement "the afr cannot change after the intake valve closes" only apply to port injection? Does vvt on the intake cam and cam lobe overlap change anything? (AFR wise)i.e. using it in an attempt for over 100% ve?

hello if im reading your question correctly the intake timing moving does have a big effect on AFR stick to your target AFR no matter what the cam timing is doing at any given rpm and load

Regards Ross