It should be higher than 11.4. That's very, very rich (lots of fuel, not enough air). 12.5 is about where you want it on a naturally aspirated motor for the best power. 14.7 is the "perfect" ratio, or stoiciometric ratio, where you have 14.7 parts air to 1 part fuel by weight and it creates a complete combustion.
And the ECU can be tuned (hopefully) to adjust this and many other parameters.