ltf+, But still 0 at WOT

[bone0918]

I was under the assumption that if you have pos.LTF's at part throttle you would not have o at WOT.The case is with my 2004 GTO is that with stock ltf settings everything looks pretty good exept + LTF's at part throttle.WOT LTF=0,02's at WOT=880,if I scale the fuel table by .95 I get - LTF's at part throttle and 0 at WOT,but 02's go into the 910-915 range.So my question is, what are the advantages here? thanks Anthony

[jimmyblue]

You get the LTFT of the last cell you were in, as your
WOT trim (if > 0.0). You can step off from various cells.
This means an episode-to-episode variation in WOT
mixture, a messy thing to tune against. You've seen
one that is zeroed but if you did a bunch of pulls you
should see some 0, some + WOT trims.

Try capturing your Delivered Torque PID under both
tunes, and plot it like a dyno curve; get pull run-up
segments into Excel and overlay them and you can
see right off whether you're getting better or worse
results.

You can be more surgical in your tuning to address
smaller regions. I believe the IFR table is probably not
your pony; more likely you ought to slightly reshape
the MAF table (for purposes of increasing the reported
airflow this is OK; decreasing it can have negative
consequences for the tranny etc.). If you can map out
the MAF and the trim cells in question, and smoothly
nudge the curve by the proper %, in just the trouble
spots, this might be a better way to go.

I've been told that the factory MAFs run about +/-1.5%
by a calibration shop I was trying to get procing from.
Unfortunately the calibration costs more than the unit....

Modified exhaust puts this all into a more questionable
position because the O2s get whacked at low heat
output, and take the trims with them.

[bone0918]

I have an m6 so the torque pids are out the window for me,but good info. thanks

[jimmyblue]

I think you still will have the Engine Delivered Torque
available to select for logging; on an M6 it should be
straight-scaled rather than have the funny business
that tries to guess the converter multiplication. I think
the PCM still uses / creates the torque PID regardless
of trans type, it's an index to several engine mgmt /
torque mgmt functions. Worth a look just as an
available performance feedback metric.