when running a non-oem tune, you can run lean...My $.02...you may not know if your lean by the o2 sensor method of cel nuke mentioned if your sensors are off (which i found is quite popular with tuners unless specifically asked to leave them on)...dyno tune if concerned...

 

When you say non-oem tune, do you mean like a canned tune?

 

yea, anything that didn't come from Ford...My point was to watch closely if you have your o2 sensors turned off, and even more so if you are not running an A/F gauge

 

Not true actually... The only O2 sensors that get turned off are the rear ones that are there to monitor if your catalytic converters are functioning properly. The forward O2 sensors that are actually telling the computer whether the mixture is rich or lean is always on.

As an aside, I ran a tune prior to installing the supercharger and the air/fuel was always between 14 and 15 according to my wideband unless I was getting into it.

 

Where does an A/F gauge pick up the samples of mix for its readings?

 

When I got my supercharger put on I didn't have the stock air box and had a steeda CAI on it that caused me to run lean for about 8 months and my engine didn't blow. I was running at 14:1 before I got my dyno tune that put me at 12:1, I'm pretty sure 14:1 is considered extremely lean and a good way to cook something, I'm lucky I didn't hotrod my car that much.