WHAT is the deal with this......

I've been trying to cure some REAL audible knock that I've been seeing - at 120º ambient with the A/C on there's a pretty good load on the engine and during rapid throttle transition it'll audibly knock

So here's my conundrum: From 1800-3600rpms and .32-.72 gms/cyl I'm 5º-7º LOWER than my previous timing table was. Now, I've pulled ALOT of timing from this table but I keep getting faster 0-60mph !!!....my best time during the winter was 5.9sec, now I'm again running 5.9sec but it's 80º warmer out and the A/C is on ?!?!, in fact I've knocked off a full second 0-60mph TODAY working on this knock issue (6.91sec this morning before tuning....5.93sec this afternoon after tuning as measured by HPTuners scanner)

Have I been inaudibly knocking THAT BAD....or does this particular head/cam combo just like less timing down low ??

 

Have you been logging KR? Also have you verified that your commanded timing was making it through to the actual tune (i.e. was the PCM preemptively pulling timing? And yes, it can and will do that -- thats all burst knock is).

 

Yes, I've been logging KR, I finally got rid of my false knock issue....all KR (when/if it occurs) is now REAL AFAIK, I've tested this by reducing max KR to 0 and seeing if KR still shows up....false KR WILL. And I'm logging timing to ensure that what I actually get is what is commanded. Burst knock isn't an issue...it works the way it should now, I've been turning burst knock off to tune out the actual knock so I don't rely on Burst KR to fix the real issue of actual knock.

I'm just suprised that I'm making MORE power than I was with considerably LESS timing than I started with (in that range anyway...I'm +10º higher up....

 

More timing isn't always best. There is a point where peak power occurs, then a few degrees beyond that that you can run without getting KR. sounds like you were beyond that threshold...

 

Where I get most of my AUDIBLE knock is during rapid throttle transition....if I'm cruising @ 2000rpm and pop the pedal down and back up quickly it'll rattle BAD during the throttle depression, At WOT the knock is non-existant (mostly...I get too crazy with the timing and it knocks audibly obviously)...any ideas on this ??

 

work with your "tip-in" knock tables, that governs knock levels at the rapid acceleration

by setting max knock retard to 0 in the tune it will never pull timing, that's a no-no and has nothing to cure false knock, false knock can be reduced by lowering the level of the knock sensor sensitivity. all you did was tell it to never pull timing, knocking or not

 

I set max KR to 0 to test for false knock, false knock will show up NO
MATTER WHAT setting is in the max KR table....I've tested this time and again and it works EVERY time, you still see 1-2 deg of KR when it's false knock if the table is Zero'd.

I'm gonna start a new thread with my results of this mornings logging.....things have changed....

 

I am liking this thread, I have similar problems occasionally.

 

I was trying to fix it the wrong way....here's the thread with the solution.

https://www.performancetrucks.net/fo...d.php?t=368012