Tech 2: Difference between 'knock retard' and 'total knock retard'

[skpyle]

Hello All,

Random question about Tech 2 data. Under 'Ignition Data' in data monitoring, what is the difference between 'knock retard' and 'total knock retard' values?

Background: Upon reviewing the datalog I sent back to Black Bear after downloading their tune to the ECM and TCM in my 2013 Escalade ESV, Black Bear reported that I could use better fuel. I was concerned, as I always run 93 octane from the same QT gas station.

Since then, I have been trying different QT gas stations, and different brands of gasoline. All 93 octane. I am using 'Live Plot' on my Tech 2 to monitor data as I drive, trying to determine how much ignition knock is occurring.
I am monitoring the following parameters:
Engine RPM
Engine Load
Total Knock Retard
Vehicle Speed

I have recorded pretty much the same results for all the gas stations and brands: part throttle knock averaging 3-5 degrees around 1500RPM and 60MPH, when the road grade slightly increases.

Now, I inadvertently selected Knock Retard instead of Total Knock Retard. This test, the knock registered was far more violent and frequent. Around 8 degrees and far more frequently.
Tonight, I tested again, this time I selected Total Knock Retard. And the info was back in line with previous tests.

Soooo...what is the difference between 'Total Knock Retard' and 'Knock Retard'?


Also, no photos. It is sketchy enough looking at my Tech 2 (briefly) while driving, but taking photos of the screen isn't going to happen. And I have not yet figured out how to 'take a screenshot on the Tech 2' so to speak.


Thanks for your time!

 

[swathdiver]

Hello All,

Random question about Tech 2 data. Under 'Ignition Data' in data monitoring, what is the difference between 'knock retard' and 'total knock retard' values?

Background: Upon reviewing the datalog I sent back to Black Bear after downloading their tune to the ECM and TCM in my 2013 Escalade ESV, Black Bear reported that I could use better fuel. I was concerned, as I always run 93 octane from the same QT gas station.

Since then, I have been trying different QT gas stations, and different brands of gasoline. All 93 octane. I am using 'Live Plot' on my Tech 2 to monitor data as I drive, trying to determine how much ignition knock is occurring.
I am monitoring the following parameters:
Engine RPM
Engine Load
Total Knock Retard
Vehicle Speed

I have recorded pretty much the same results for all the gas stations and brands: part throttle knock averaging 3-5 degrees around 1500RPM and 60MPH, when the road grade slightly increases.

Now, I inadvertently selected Knock Retard instead of Total Knock Retard. This test, the knock registered was far more violent and frequent. Around 8 degrees and far more frequently.
Tonight, I tested again, this time I selected Total Knock Retard. And the info was back in line with previous tests.

Soooo...what is the difference between 'Total Knock Retard' and 'Knock Retard'?


Also, no photos. It is sketchy enough looking at my Tech 2 (briefly) while driving, but taking photos of the screen isn't going to happen. And I have not yet figured out how to 'take a screenshot on the Tech 2' so to speak.


Thanks for your time!

Can you make sense of these posts? My eyes are hurting and can barely read them.

"Total Knock Retard" Vs. "Knock Retard" Check out Log

Check out my log here. It's showing absolutely 0 knock retard but in the last cell at the bottom of the left column, the "Total Knock Retard" IS showing knock. Whats the difference between the two? Why is it showing up there but not under knock retard?

forum.hptuners.com

Parameter Descriptions

At the bottom of the screen are some menu options, to the right you can select more options and somewhere is the option to take a Quick Snapshot. Press that to begin recording and press exit to stop. Then you can replay it later. When replaying, you can do a live plot too.

 

[skpyle]

Can you make sense of these posts? My eyes are hurting and can barely read them.

"Total Knock Retard" Vs. "Knock Retard" Check out Log

Check out my log here. It's showing absolutely 0 knock retard but in the last cell at the bottom of the left column, the "Total Knock Retard" IS showing knock. Whats the difference between the two? Why is it showing up there but not under knock retard?

forum.hptuners.com

Parameter Descriptions

At the bottom of the screen are some menu options, to the right you can select more options and somewhere is the option to take a Quick Snapshot. Press that to begin recording and press exit to stop. Then you can replay it later. When replaying, you can do a live plot too.

Thank you for this!
Sorry I have not replied sooner. I am in the middle of replacing the head gaskets on my wife's 2008 Equinox LTZ 3400, so I got a little side tracked.
I will review these posts tonight at work.

 

[swathdiver]

Thank you for this!
Sorry I have not replied sooner. I am in the middle of replacing the head gaskets on my wife's 2008 Equinox LTZ 3400, so I got a little side tracked.
I will review these posts tonight at work.

Equinox's were running the 3400 back then? I thought that engine was retired by then. What happened to it? We've still got one of those motors in our stable.

 

[skpyle]

Equinox's were running the 3400 back then? I thought that engine was retired by then. What happened to it? We've still got one of those motors in our stable.

Yep. 2008 had the LNJ 3400. This one started overheating after long drives on the highway, then idling on surface streets. Found that the fire ring was seeping coolant for #1 cylinder. So... I had the heads refurbished and am replacing the head gaskets. As well as a bunch of other WYAIT maintenance.

#1 cylinder combustion chamber. The head actually had a tiny shallow spot from the coolant seeping.

Refurbished cylinder heads: bead blasted, surfaced, new exhaust valves in accordance with the TSB, new valve springs, and a valve job.