I run 820s at 1650. How many times we gotta say that the stock oem O2 is basically meaningless once it leaves the mid point?
It is called a narrow band sensor which means it is only accurate in a narrow band and that narrow band is centered in the middle of the range.
Then, we have to learn that there is no magic number. One guy's car may run best at 1525 and another's at 1675 with the same egt gauge. Combination affects performance ranges.
You start with a base line and go leaner, if it goes faster, you go leaner again, until it either slows down or starts detonating. If it goes slower right off the bat, then you go richer until it quits going faster and then you back up to the prior point. Look at your egts and shoot for that number until you change something.
There are NO magic numbers-only what works in your car. It is a lot easier to tune these cars if you ignore folk lore and take the time to find out what works for you.
