I did not know this, but it makes sense. Thanks for sharing.Most O2 sensors are narrow band, they just basically tell the ecu if you're rich or lean (under or over 14.7).
A wideband O2 is more accurate and will tell you exactly what the air/fuel ratio is. When a car or engine is on a dyno they use one, and it allows the tuner to adjust the fuel and spark for best performance.
My mustang is supercharged and has a digital gauge on the steering column that uses a wideband O2 mounted in the exhaust system and tells me exactly what my a/F ratio is all the time. So when I'm at full throttle I can visually see if it's going lean and get out of it before anything bad happens. I like it around 12.1 to 12.3 and a wideband will be able that accurate. Sometimes it will be 11.8 or 11.9
An engine makes best power between 10.5 and 13 depending on the engine setup and whether it is naturally aspirated or boosted.
Interesting side note: In piston-engined aircraft, we now track EGT and CHT on individual cylinders, and adjust the mixture to either very rich (100ºF+) or lean (50-100ºF) of peak EGT (average) to get our mixture set just right for climb, cruise or descent. People operated aircraft for decades about 50ºF rich-of-peak EGT to supposedly keep the exhaust valves cooler. Cylinders would last maybe 800 hours. It became just SOP to plan on replacing cylinders at least once during an engine's TBO run. Then along came some engineers in Tulsa who figured out how to put pressure transducers inside of each cylinder to record internal cylinder pressures. They discovered that peak internal cylinder pressures happened at about 50ºF rich of peak EGT - right where everyone had been taught to run them. And, that meant it was also where there was the highest chance of pre-ignition, and where combustion events generated the most heat as a result, which of course went right into the material of the cylinders making them harder to cool effectively.
Long story short, switching to running the engines on the lean side of peak EGT, which everyone was afraid to do due to decades of 'conventional wisdom', makes the cylinders last more than twice as long, with lower fuel burn. Go figure. Funny thing about it though, they looked back at the old Pratt & Whitney operating manuals from the WWII era and found that lean-of-peak is the way they recommended their piston engines be run way back then. Somehow, an entire industry had gotten it wrong for decades between WWII and around 2005.