generally speaking it will be the same as for any other engine.....stoichimetery is 14.7 which is too lean for optimal power but what all auto's try to stay at for emissions reasons.
for max power one generally will try to see 12.8-13.1 at WOT, up to 13.5 in the mid range and up to even 13.8-14.0 from idle. this is how my is tuned and runs the best.