its good. perfect is 13.0 at WOT 14.7 is perfect for cruise sounds like you dead on! under WOT your making lots of HP so you have to run it richer. but in cruise where your only making 50-80HP you can run it leaner and its totally safe! for FI cars the WOT is even richer. 11.5-12.0 depending on the build

 

Awesome, thanks. I was reading on another forum and they were telling someone that 14's is dangerously lean, but I believe it was a turbo import that they were talking about.

 

Sounds spot on to me.

Under part-throttle (cruise) condition, the fuel system normally runs in closed loop, which means it constantly monitors the (pre-cat) O2 sensors and adjusts fueling. Since stock O2 sensors are narrowband, you can't use them to know exact AFR, they just tell you "leaner than 14.7" or "richer than 14.7". So the computer keeps adjusting fuel to basically dither between "a bit lean" and "a bit rich" (that way it knows it's right around the sweet spot). The end result is that AFR constantly moves between something like ~13.5 and ~15.5. This is true I think for most modern cars.

 

So if I'm at 90% throttle and it's adjusting it to 14.7, wouldn't it be a bit lean?

 

Well, 14's AFR is dangerously lean if you're at WOT. My GTO likes 12.5-12.6 best on the dyno (makes the most power). Normal cruising the AFR will try to stay at about 14.7 (give or take a little). You're good, no problem.

 

14.7 at 90% throttle is definitely too lean.

I'm guessing that anywhere above 30-60% throttle the computer switches to open-loop mode maps for ~12-13AFRs.

 

on a stock GM tune calibration for an 06 GTO, WOT/PE mode becomes enabled after 15 kpa MAP, 48% throttle (from 0-3100 rpm) (then 28% and less throttle from 3500rpm and up) ,

 

With my WB it reads 12.1 at WOT NA and 11.8 at WOT on the 75 shot. Does this sound right for the Na reading?

 

It is recommended for WOT on a NA engine to run between 12.8-13.2. Now where your specific engine makes the most power within that range is where it should be and obviously a dyno can tell you that.

As far as the nitrous goes I am not too familiar with tuning for it yet so I will let someone else chime in on that one. Adding fuel during the shot is definitely correct but as to how much I do not know.

 

each has there own opinon on AFR for N/A myself i think the 12.75 mark is about perfect. others claim 13.0 so its a wash. With different CAI's/TB/Intakes/Cam's/etc your AFR can Very under WOT. for instance my C5Z06 is at about 13.0 at 2700rpm, 12.9 at 3400rpm, 12.8 at 4400rpm, 12.77 at 6000rpm, 12.74 at 7000rpm.

My friends firehawk likes the 13.0 AFR at 6500rpm

Each setup flows differently making the power Curve different on each application, in such a PERFECT AFR cant be said for every setup. To fix this the Motorhead god has given the ability to measure HP/TQ with a dyno!

In short aspect, as long as your not over 13.4 AFR or under 12.0 AFR N/A you should be fine.

 

Yep, different combos may like slightly different A/F ratios and the same combo may like different A/F ratios at different RPMs, and different widebands will read differently. You're guessing on the absolute best A/F without track testing or dyno testing, but in GENERAL as has been said 12.7-13.2 is fine for WOT. 14.7 is a "perfect" mixture for emissions, and you run richer to cool the cylinder and prevent scorching or detonation. Hotter intake mixtures (forced induction) require more cooling, so richer A/F ratios.

 

As a general guide