Factory widebands are not sufficient for tuning rich forced induction engines. For starters, the actual number displayed is not accurate, and much less so on the richer end of the scale. It's fairly close around 12.7 to 14.7. The richest value displayed is in the 11's.
AEM widebands are cheap....$270 through us. I strongly suggestion a wideband if you stand a good chance of success. EGT is a nice to have, but not required.
iPhone..excuse typos.
