2G knock counts and timing

[pickens]

I got tired of searching for it, but I want to know how much timing a 2G ecu pulls for a given knock count. I remember seeing that around here somewhere. I figure I can correlate how much knock I have with the timing curve while I tuning my AFC.

 

[kpt4321]

Approximately 1 degree of retard for 3 counts of knock.

 

[pickens]

I just thought about something. If I leave all boost settings constant, and only change fuel corrections, then any timing change should be indicative of knock. Right? Or I presume I will need to somehow consider the airflow map the ecu is on as well because as I lean things out, I am also telling the ecu to switch timing maps. Hold on, I just confused myself.

 

[kpt4321]

You're right. If you make a fuel change with the SAFC, what you are really doing is lying about the amount of airflow entering the motor. This will cause a timing change whether you are knocking or not.

 

[pickens]

So then how do I decide if its knocking? I guess when I tune it, I will just keep leaning it out until my timing takes a dive. I can't see no other way of how tune w/ the AFC.

 

[doug]

Originally posted by kpt4321
Approximately 1 degree of retard for 3 counts of knock.

You're obviously a wiseman for a reason. DSMLink tells me it's 0.35 degrees of retard per count, which would come out to 1.05 degrees for 3 counts.

And pickens, yeah, that's the way I understand it, but I know practically zero about AFC tuning.