OK well my afr reads from 21.0 to 9.5.. And I thought that the lower the # the leaner... So I would want to tune it to around 11.1? It doesn't read 11.0:1 or 12.0:1.

 

The :1 ("to 1") part of the ratio is assumed so, 21.0(:1) = dead lean and 9.5(:1) = pig rich. If you don't have the gauge installed yet, you will see how it works when you do. You should see >18.0 (lean) during decel, <11.5 (richer) at WOT and for constant-throttle driving, it should hang around 14.7. If you are mostly stock and have no fuel tuning yet, that WOT AFR will more likely peak around 10.0 (ie. really rich).

It's always best to start richer than you need and work your way leaner while keeping an eye/ear out for knock. If you start to get knock, you've gone too lean and will either need to richen it back up in the area of knock, turn the boost down or use a higher octane fuel.

With that said, yes, most people seem to tune to 11.0-11.2 AFR depending on mods, available pump gas octane, boost level, etc.

 

Ah got it now.. And yes it is installed and it runns around 14 give or take for constant-throttle driving. But when I get on it, I see it very from 13 to 11.5.. So if what you saying is true the my ish is running really lean at some points at WOT.. So @ WOT I want it to stay at 11.1 or 11.2 then..

 

That's Correct .

 

What VTECH8TR said

As for the 13:1s, it really depends where it happens. If it's WOT, but BEFORE reaching 5-7psi, it's less of an issue. You should be pretty close to your 11.0-11.2 over 10psi and definitey at it by the time you hit full boost. If it hits the 12-13 AFR range when it hits full boost, or anytime after hitting full boost, you'll want to richen those spots up.