So i decided to start this thread after a little motivation from Sinister. This may help out people in the future looking to know the difference between a wideband afr and a narrowband afr.
Quoted by Sinister:what does a wideband read?Narrowband only reads between 11 and 21.
A proper tune will be riding the line of 11.... so you'll never know if you're tuned perfectly or if it's maxed out.
A narrowband is necessary for the computer to be able to maintain a stoich air to fuel mixture. (14.7). But Stoich for certain fuels can be as low as 9 (E85) or lower if you're running straight alcohol. The 14.7:1 is calculated in closed loop, but as soon as you're wide open throttle, the ECU moves to an open loop system and no longer uses the narrowband AFR.