When you see KR, do you adjust timing based on average KR in the historogram or max? IE sometimes ill get 2-4 deg of KR for a frame or 2 but average KR in that particular cyl airmass vs. rpm averages 0 KR (An exception)

Any input is appreciated.

Dave

 

i recently got some kr on a too agressive lean out, it was pretty obvious on the histogram where it mated with the surrounding (+11 ltrims). So i would just add more fuel in that region and i'm guessing it would go away. Car has never knocked in that area before mid-light throttle 30% with a buttload of timing.

you watch your histograms or log or what? you gotta break it down to the VE/Timing style format and work around the fuel/timing issue.

i never got any knock cept when those pace-suckahs were rapping or when i was playing mr tuner on some conceptual ideas that didnt pan out lol.

 

I don't use the histogram at all. I work purely in Excel
and eyeball it frame by frame. When I see KR I try to
figure out whether it's spark or fuel, by looking at the
O2 voltages in the current and prior frames and the
amount of spark actual. In general I've seen the KR
event preceded by an O2 dip. Eliminating PE mode delay
(or way lowering the delay mode RPM) and making sure
the enrichment rate is large, fattening up the VE table
about points at or preceding KR, seem to have done it
for me.

When you have it down to only occasional KR it's
easier to work this way. If it's all over you then some
broader work has to be done I reckon.

My goal is zero KR because best torque is before
ping and KR is after ping.

I have also done a lot of selective spark table
massaging, bumping up timing where it seems to take
it and pulling back wherever I see traces of KR. The
global add is a not-terrible way to get some more
power and this is how a lot of people start (and what
the handhelds do) but you have to play whack-a-mole
with it for a while before you can get to truly optimized.

Now, I think a cool tool would be an Excel macro that
would rake through an exported data file, and sift the
sheet for the CylAir, MAP, RPM, O2 points that lie on
either side of an increasing-KR data cell boundary, and
put a list out - condense it to just the bad boys and
make it easy to go from that right to the spark or VE
or PE tables' relevant nodes. But I'm no ExcelMeister,
that way.

By the way, I think if you haven't, you should knock
the attack rate down to something like 0.1 - 0.05 and
up the decay rate to 0.2 - 0.3; this will really reduce
the harsh jump-up (who needs 4 degrees on the first
ping?) and make it go away a lot quicker. If there is a
persistent ping it will still "motorboat" along at the
roughly-right pullback, just take another tenth of a
second to get there.

Also up your burst knock threshold to something like
0.05 and you should not see BK except on throttle
transients; 0.01 delta CylAir may let it trigger on
simple acceleration airflow run-up, 0.02 was enough
for a mild-mods truck, play with the trigger value
if you see a lot or KR in first, less in second and none
in third. Also I pulled back my whole BK/RPM table to
2.00; if you suspect BK as part of your KR readings
you could "tag" it like by setting the table to 2.222
or something unique and seeing if that just happens
to be what you get for KR.

 

thanks for the help. my burst knock in the higher RPMS is .200 (stock setting) and my attack has been raised to about .500 (I changed earlier this year). i see very little KR. usually its just right between shifts or as of the last day on a standing light acceleration if i let it bog. I did notice that my o2s go down to .0xx usually before i get this KR, should i play w/ the ve table in this area? Raise VE so it adds more fuel??

Dave

 

If your O2's are going that low then yes I would add fuel to those spots and the cells just before

 

its only showing that voltage for 2 or 3 frames (2 tenths of a second) this isnt normal ?

Dave

 

does it match up with your KR?

 

This is a good thread... real info I can use....

 

By the way, I think if you haven't, you should knock
the attack rate down to something like 0.1 - 0.05 and
up the decay rate to 0.2 - 0.3; this will really reduce
the harsh jump-up (who needs 4 degrees on the first
ping?) and make it go away a lot quicker. If there is a
persistent ping it will still "motorboat" along at the
roughly-right pullback, just take another tenth of a
second to get there.

Are you speaking of the attack rate vs. RPM??

Also up your burst knock threshold to something like
0.05 and you should not see BK except on throttle
transients; 0.01 delta CylAir may let it trigger on
simple acceleration airflow run-up, 0.02 was enough
for a mild-mods truck, play with the trigger value
if you see a lot or KR in first, less in second and none
in third. Also I pulled back my whole BK/RPM table to
2.00; if you suspect BK as part of your KR readings
you could "tag" it like by setting the table to 2.222
or something unique and seeing if that just happens
to be what you get for KR.[/QUOTE]

Is this the Burst KR vs RPM, or Delta?

 

im seeing alot of spots where if i put the motor under quite a load at lower rpms (6th gear at 2000 rpms) my o2 voltages go to the double digit area and then i get KR. Could you elaborate more on this? Will modifying the ve table when this occurs actually keep hte o2 voltages from getting as low as double digits??

Thanks
dave

 

usually just before yes, but how to cure exactly? Do i go to the cells just before ? if so usually they are way lower in the table im guessing then where ive accelrated to.
Dave

 

check this out: my voltage before knock: suggestions?

 

is this 6th gear light load roll-ons?

 

no this is many different gears, check this out as well. Just before the KR spikes, the o2 voltages are down in the double digits causing the KR im assuming:

 

what MAF do you have?? and have you altered the setting for it?? Also have you done anything with the DFCO setting

 

stock 00 C5 MAF and stock VE tables. I just added an ls6 intake so this might be part of it as i dont recall this much KR before. especially not tip in

Dave

 

might want to try Q-tipping the MAF. If not then pull 1-2* timing that should fix it up

 

i dont think this is timing related so much. Primarily because of the drop in o2 volltages just before KR usually. Plus mostly where its knocking im at a stock C5 timing value. On a side note, i do notice a max of .02 g/cyl more cylinder airmass after the LS6 intake. possible clue it flows more needed VE changes?

Dave

 

thats true...

 

but any other input is appreciated. Im going to try to clean the MAF just to see.

Dave