[Camaro1973]

Originally Posted by FoundNemo

The explanation was that the knock is built in timing retard based on IATs and COT related timing tables/heat, not based on knock sensor activity. Is that not the case per the logs?

No that’s incorrect. The ecu sees knock and pulls timing accordingly. However, knock could just be because of high air temps, cylinder etc. but regardless knock is knock like LT1 said. Now you just need to see if it’s real knock or not. If it’s real knock you’ll clearly see puffs of gray smoke when it shows knock. (Generally speaking).

[FoundNemo]

Here is a clean pull in 3rd and 4th with everything logged. The knock is absolutely identical everytime across RPM. Knock per cylinder is zero, but the Total Knock Retard shows 4.9 to 3.0. I'm betting this is burst knock retard and not actual knock, since there is no knock in the cylinder knock tables or the knock retard value, but the Total Knock Retard (which includes burst knock retard/preventive).

I added in 4 gallons of MS109 to the 93 blend and drove on it a bit with one WOT pull before I logged these. Zero change in Total Knock Retard, showing 4.9 initially dropping to 3.0 at peak RPM. However, there are no knock counts on the per cylinder knock items again and the "Knock Retard" is showing zero, despite the "Total Knock Retard" showing 4.9 to 3.0. Any thoughts folks? I really appreciate the input.

[Camaro1973]

Originally Posted by FoundNemo

Here is a clean pull in 3rd and 4th with everything logged. The knock is absolutely identical everytime across RPM. Knock per cylinder is zero, but the Total Knock Retard shows 4.9 to 3.0. I'm betting this is burst knock retard and not actual knock, since there is no knock in the cylinder knock tables or the knock retard value, but the Total Knock Retard (which includes burst knock retard/preventive).

I added in 4 gallons of MS109 to the 93 blend and drove on it a bit with one WOT pull before I logged these. Zero change in Total Knock Retard, showing 4.9 initially dropping to 3.0 at peak RPM. However, there are no knock counts on the per cylinder knock items again and the "Knock Retard" is showing zero, despite the "Total Knock Retard" showing 4.9 to 3.0. Any thoughts folks? I really appreciate the input.

More than likely its not real knock, esp if you added vp 109. Would be more jagged in the graphs if was actual knock. I wouldnt be too concerned about it. Also, its hot as ballz outside, your MAT temps are 150F+. Wait for a nice 60 degree night


I just took mine out today and my IAT 1 was like 106... LOL. Not going to make any decent power with those temps.

[FoundNemo]

Originally Posted by Camaro1973

More than likely its not real knock, esp if you added vp 109. Would be more jagged in the graphs if was actual knock. I wouldnt be too concerned about it. Also, its hot as ballz outside, your MAT temps are 150F+. Wait for a nice 60 degree night


I just took mine out today and my IAT 1 was like 106... LOL. Not going to make any decent power with those temps.

Cheers to that, thx!

[wnta1ss]

Is this your friend's car with the CSP headers etc just added?

Possible that Camaro1973's idea of false knock is right. You've already read the new tune from this car, correct? If so, take a look at this: Engine>Spark>Retard>Static Retard>vs Cylinder (that is a button) table and tell us what's in there (or a screenshot).

[KingLT1]

False knock...need to desensitize the sensors even further. They are ultra sensitive on the LT stuff...GM sets the LT1/4 to live on the knock sensors. These sumbitches always showing false knock until you get the sensitivity dialed back.

[FoundNemo]

Originally Posted by wnta1ss

Is this your friend's car with the CSP headers etc just added?

Correct, my buddy's car with CSP headers just added. Possible that Camaro1973's idea of false knock is right. You've already read the new tune from this car, correct? If so, take a look at this: Engine>Spark>Retard>Static Retard>vs Cylinder (that is a button) table and tell us what's in there (or a screenshot).

Here is a snapshot and I attached the tune itself in a ZIP file. Interestingly indeed under, the 4.9 hits up front around 3200rpms and tapers down to 3.0 right around 4800rpms. If this is the reason for the retard, why is it listing in Total Knock Retard vs just timing advance just going down (as it does with IAT, ECT, etc)?

[wnta1ss]

Originally Posted by FoundNemo

Here is a snapshot and I attached the tune itself in a ZIP file. Interestingly indeed under, the 4.9 hits up front around 3200rpms and tapers down to 3.0 right around 4800rpms. If this is the reason for the retard, why is it listing in Total Knock Retard vs just timing advance just going down (as it does with IAT, ECT, etc)?

I don't know why gm set this table to give false knock, seems stupid af to me. Anyway, zeroing this table out fixed the false knock that I had been seeing.

[FoundNemo]

Originally Posted by wnta1ss

I don't know why gm set this table to give false knock, seems stupid af to me. Anyway, zeroing this table out fixed the false knock that I had been seeing.

Thank you very much. Upon further research, Total Knock Retard does include this table as "knock" that wont show up anywhere else. As such, zeroing out the table fixes the false knock that is 100% consistent across RPM regardless of gas quality or octane. Found multiple posts on HPTuners about it. I will have my buddy load her up and pull some updated logs. Doordash food my treat wnta1ss if you want to PM me, will send you dinner for your help!

Another post on the vette forums about the same exact thing. Apparently that timing retard has to do with which cylinder gets less fuel (supposedly). We are quite certain this is what is going on now.

[KingLT1]

I was assuming prior that this table was already addressed since it was "tuned". Should of known better...lol

[Camaro1973]

Originally Posted by FoundNemo

Here is a snapshot and I attached the tune itself in a ZIP file. Interestingly indeed under, the 4.9 hits up front around 3200rpms and tapers down to 3.0 right around 4800rpms. If this is the reason for the retard, why is it listing in Total Knock Retard vs just timing advance just going down (as it does with IAT, ECT, etc)?

Who tuned this thing? Whoever did left some pretty basic stuff untouched.


I think Matt Pekham (Nickey) explains this table and the static retard GM puts into this table in one of his videos.

[FoundNemo]

Originally Posted by Camaro1973

Who tuned this thing? Whoever did left some pretty basic stuff untouched.


I think Matt Pekham (Nickey) explains this table and the static retard GM puts into this table in one of his videos.

Gonna leave tuner name out for their privacy. Nuff said that this was zero'd out with no other changes and flashed and retested. Zero total kr, runs strong. He is super happy, thanks so much! Will post the wot logs shortly.

[FoundNemo]

Originally Posted by Camaro1973

Who tuned this thing? Whoever did left some pretty basic stuff untouched.


I think Matt Pekham (Nickey) explains this table and the static retard GM puts into this table in one of his videos.

Here is the pull in 3rd at WOT. Zero knock now with the Cyl #1 static retard zero'd out. No more rev limiter hits with it bumped up 100rpms for max now too.

[radz28]

Excellent progress