Originally Posted by Danja 
Haha hey man, sorry I didn't answer your PM yet. Been kinda busy.
As for the question in your PM, yes, it's supposed to jump back and forth form 14-15 at idle. You are seeing your ECU adjust fuel based upon O2 sensor output to keep it there (since 14.7 is stoichiometric). And yes, it's supposed to go all lean when you engine brake because the injectors shut off.
As for the ratio, it depends on your setup. However, it is a well known fact that you will never combust all of the fuel which it would be possible to react with the given amount of oxygen. Keeping this in mind, it's easy to see that tuning to run stoichiometric will actually cause you to run lean (very bad!!) because not all the fuel will burn completely. Therefore, it is generally accepted that for best performance, you should run your engine a bit on the rich side. How far rich you run depends on your setup.
For turbo or supercharged vehicles, you need to go as low as 10.5-12 in order to stay safe. For naturally aspirated vehicles (like my own), there is less danger of knock, and the mixture can get away with being leaner. Since I have no dyno for testing, and not much tuning experience, I can't tell you what's best for your mods. However, I found that running about 13-14 for my car seems to have improved it somewhat.
Unfortunately, SAFC is an inexact tuning tool, so it's hard to keep it in a narrow specific range. And, without being able to adjust timing maps, it's pretty limited as far as what you will gain from it. But, it is great fun to mess around with and see what you can do, and it will at the least allow you to make a little more from your mods (just be careful and stay away from the lean side!!).
Any more questions you have, there are lots of people here to answer! Have fun!
But if I run it on the rich side, wont that cause me to burn more fuel? See what I'm tryin to do is tune it to unlock maybe some extra horses but at the same time, making it more fuel efficient. Is this possible?
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