At 08:01 AM 11/16/00 -0800, you wrote:
>Under load, though, you go out of closed loop and O2 sensors aren't being
>used. Does the 14.7:1 still apply or do the other built-in tables come into
>play? Ron
In open loop, the 14.7:1 does not apply. This afr is used in closed loop
because this ratio ensures that current OE cats operate at their most
efficient. Unfortunately, it also the ratio at which pinging problems
could most likely occur.
In open loop, the built-in tables (which are based on R&D historical data
for a specific engine) are used. The afr part of these tables are
deliberately
on the more-than-needed rich side for 'warranty' reasons. How rich, I have
no idea. While there is much argument as to what the ideal afr for max.
performance
is, I really got the impression from Zimmer that the afr in these built-in
tables are richer than the ideal performance afr range.
Bob. Burlington, Ont., Canada.
'97 Dakota CC, 5.2L, 4x2, 3.92 SG, auto., 4265 lb.
Dyno: 231.2 rwhp 340.0 lb-ft rw torque
PB: 14.737 @ 91.75 9.364 @ 72.95
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