Q:

How many edits to question for it to become community wiki?

How many edits to question for it to become community wiki?
I've found posts about answers. Not about questions.

A:

Since April 2014 no amount of edits can trigger automatic wiki conversion. This was announced at MSE, in Stop using community wiki as a reputation denial mechanism:

we have removed all of the automatic triggers that convert a post to community wiki. Edits by the original author, edits by other people, and even volume of answers, all of these no longer cause a post to be automatically converted to community wiki...

More than that, this approach applies retroactively as recently explained by Director of Community Development for the Stack Exchange Network (Robert Cartaino):

Note to Moderators: If anyone requests removal of a forced Community Wiki setting, it should be removed without hesitation (unless the author set it for their own answer or other extenuating circumstances).

With regards to CW removal another thing worth keeping in mind is that when it happens reputation is recalculated as if the post was never a wiki and since June 2014 recalculation effect becomes immediately visible. 

