Air Fuel Ratio
 

I just got done installing SLP LT's, catted X, Accufab 75mm TB and Plenum, and My AEM UEGO A/F Gauge. I also loaded my tune that was supposed to be for my car with the mods I have so far including those I just listed with the X-Cal. My air fuel is reading between 14.5 to 15.1. How dangerously lean am I and can I use my X-Cal somehow to add more fuel or do I need to send for a new tune and reload it. Thanks.

You can add fuel with the programmer but I Wouldn't. I would take it to a local tuner and let him dyno tune it for you. Around here where I stay it's only $100 an hour and I doubt it will take them an hour to do.

Do it yourself, youve got a good a/f gauge, thats all you need. Im assuming 14.5-15.1 is what you're getting at WOT? If thats what you're getting while driving around town then thats normal, but WOT runs shouldnt be any higher then 13.0.

The numbers I gave are at idle. I havent gone WOT yet because of where the A/F was. Im wondering if there is something wrong with the gauge. I should be able to pull my plugs and check if it is running that lean correct? The closest dyno is 2 hrs away. So I'm trying to avoid that. How do I use my X-cal to make adjustments. I have just loaded tunes so far with it. SO at idle 03gtmustang 14.5 - 15.2. that is normal? Thanks.

Thats a good a/f, you're fine. Itll be the same daily driving too.

You wont really be able to tell anything by pulling the plugs on pump gas.

Cool thanks fellas.

13.0 ??

for best n/a power 13:1 is best, its lean and mean but most people want 12.5:1 cause its a bit safer (this is for n/a motors).

is the AF guage you're using wideband? If not you'll never see anything but either super rich, super lean or stoich (14.6:1). EDIT: Nevermind this line.. your is a wideband according to AEM's site.

ernest... what exactly is your question? 13:1 is a good powerful AF for cars that exist where you can get 93 octane gas. Out here in Kalifornia we only have 91 octane CARB approved gas which sucks donkey balls. Thus here we use 12.5:1 as the WOT target for max power and safety.