I've looked around and I can't figure out what "engine knocking" is. I'm sure its simple but if someone could answer this question I would appreciate it!
Knock and ping are old car guy terms describing ignition irregularities. It's a common misconception, but in internal combustion theory (4 stroke), the air fuel mixture does not ignite and explode. If it did, you would have uncontrolled combustion, which is what is referred to as knock.
You want the air fuel mixture to burn completely evenly, imagine a field of grass. The flame front travels across the field, it doesn't all go up and once. That's what produces power by creating pressure that acts on the top of the piston.
Knock is really post ignition, which can be anything ranging from the failure of the ignition system to ignite the mixture and an alternative ignition point spontaneously forming to multiple competing flame fronts hitting each other head on in different directions. This is defined as after the point at which the spark plug was supposed to fire the mixture. When it gets super volatile, it just seems to completely explode at the same time.
Pre-ignition, which is called pinging, occurs when there is extremely high pressures caused by lean conditions, too much boost, etc, at a point before the ignition system tries to fire the mixture.
Both knock and ping are detected by a microphone (the knock sensor) which listens for high pitched noises that are associated with both knocking and pinging. The sensor has a tight threshold, so it is easily fooled by noises that are not associated with post and pre-ignition. It'd really an inexact sensing method, but short of putting $5000 pressure transducers inside the actual cylinder it's the best method for detecting problems.
depends what software your using,so when looking at datalogs etc. how much knock is acceptable? at what point to you consider adjusting the timing or tune?
Didn't one of the last AP updates change from KnockSUM to Knock Count so you don't have to *.35?depends what software your using,
KnockSUM is what the ECU see's, anything above 3 is bad, but only if its consistently above 3, and above 110load...
KnockRetard (i think Cobb calls it) is just KnockSUM * 0.35, so in this case anything consistently above 1 is bad (same 110load as well)
Yup, when I did my baseline pull my knock count was maxed out on the stock tune. I think mine had alot to do with the lean spool and timing.how much that's acceptable will usually change per model of car. When I dyno'd my X (100% stock) my first run I had 12 counts (insanely too much). My tuner was datalogging and also guessed it was from the factory tune overfueling and because of the heat soak I had. My second run had 1 count. He said that was totally fine for the X.