Z06 runs rich and picks up spark retard

[03_Z06_Blue]

I am just getting into the tuning after having HP Tuners about a month. I have edited to eliminate CAGS, lower fan speeds, and raise my rev limit.
I started to use the scan and have noticed that my AFR Commanded and readings are pretty rich; typically low 12:1 from 4,000-6,000 rpm. I am also getting a small amount of KR (0.5-2 degrees) on most third gear pulls, in that same rpm range.
I always get the rich condition, and get some KR on most runs. I ran the car last weekend on a dyno, and duplicated the 12.0:1 rich ratio with the wideband probe up the tailpipe; and read the KR on my scanner.
I need your advice. Should I lean out the mixture to keep power enrichment in the 12.5-13.0 area FIRST; and THEN cut back on the advance curve (maybe a degree in the "sensitive" areas)??? Or, should I cut down the advance and maybe make the KR less aggressive, etc. first.
I would think that I should get the mixture closer to maximum power (closer to 13:1), and then work on spark; but I am not sure.
What is the best tuning method???
Thanks

[jimmyblue]

I would get your mixture right first, shoot for something like 12.8:1.
For me, that was all just PE table scaling (1.25 stock gave me 11.7,
1.15 gave me 12.7-12.8). I did not find any big KR increase from this
bit of lean-out though since you're already edgy you might. Then just
use the spark retard histogram to show you where to peel back some
timing. Note that a -lot- of LS1 cars seem to hit KR at 4000RPM, this
may or may not be true detonation.

I have revised my KR attack / recovery rates to make the action more
tolerable, and make it more obvious when I have true detonation going
on. The stock action is a big jump-up and a long tail that buries any
subsequent pings. This not only sucks from performance but hides the
true nature of the spark tune. Knock your attack rate down to 0.100
and raise your deay (recovery) rate to 0.200 and you will see lighter KR
applied, see it bleed down faster, and if you have true detonation you
will sort of "motorboat" along in light KR and light ping. KR will still rise
if you have sustained knock.

Going this way the spark retard histogram becomes clearer and more
meaningful (not filled with "residue" from predecessor cells that have
no realism in the moment). You could (as I did) go through a series of
spark advance increment tunes, bumping spark up 1 degree at a time
in any cell that -doesn't- show KR, and locally smoothing, until you have
a histogram that shows 1 degree KR all over the place. Why?

Because then you can subtract 2 degrees from the whole table and know
for a fact that you have as much spark as you can get away with.

[MNR-0]

I run mine at 12.1:1 AFR with a top end spark of 22.9 degrees and mid range peak of 25.3 degrees. Its a stock motor with exhaust, CAI mods and pulley. Seems to like it richer than leaner and for 2900lbs of car to pull in 13.00 (best) and consistent 13.1 seconds the track times seem to back it up as well.

You can try a leaner tune with less timing, but leaner means chance of KR as there is less mixture to burn. I have CATS so cant go too lean or they burn out.

[MNR-0]

Sorry, 3900lbs of car to pull, not 2900lbs.

[Watch22]

You might want to De-Carb the motor. I ran two applications of SeaFoam through mine and my dads Z06's and the knock is gone. I run 12.8A/F with 24 degrees at the high end on the high table.

[blue_falcon]

So we should change the "knock fast recovery rate vs RPM", raise it to 0.200, and change the "knock fast attack gain vs ECT/Baro" by lowering it to 0.100, is this correct?

[jimmyblue]

Not the gain, but the attack rate. This has made the KR
less of a nuisance when it does hit.

Be aware however that it also cuts the degree to which KR
can save your ass on sudden detonation. Fine for tuning,
or a vehicle that is pretty well tuned in. -Not- something
to try when you strap on the bottle and try that 150 jet
for the first time.