Correct A:F Ratio @ WOT?

[Jeff Bromberger]

i wouldn't lose complete faith in the wideband...  i just took my car to the
dyno after putting the supercharger on with the only ideas about what i was
shooting for being 12:1 and about 34 degrees of timing... it made 760hp on
9psi... i wouldn't bet $5 that its the max power that i could get out of it,
but i use those numbers as a safe starting point... if you go over there and
are running14.5 : 1 you might not get a second chance to make any changes
:-)  of course, timing will effect the readings a lot... if i'm at 12.0:1
running 34 degrees of timing and i drop the timing to 30 degrees the AFR may
go to 11.5:1... so they are definitely tied together, but if you're in the
ballpark timing-wise the afr should at least get you started... that being
said, i've heard of professional racers running big hp cars with power
adders in the range from <9.5:1 up to 13.0:1... so Bruce is right, forget
about picking the perfect number without some trial and error...

>
> So that sort of sucks.
>
> How often, on an optimally tuned engine, does the A/F ratio deviate
> significantly from the "slightly rich" range?  Or, perhaps, how often
> does the A/F ratio (on an optimally tuned engine) run lean?
>
> Is the AFR really that poor of a way to tune?  If one has no other tools
> in your box to tune with, can you do anything worthwhile with a WB sensor?
>


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