how much knock is acceptable

[ryans1000]

I know zero knock is the goal but seems like a lot of people see knock here an there.

How much knock retard is acceptable on say a 500-600whp ls1? And at what point is it crital / engine threatening .

[GAMEOVER]

IMO...at WOT I don't want to see any knock at all.... Especially on a boosted motor!!!...:D

[WeathermanShawn]

Boosted you may not want to see any.

On non-boosted, depends on how much you trust your knock sensors. If you have differing spark values on your High and Low Octane Spark Tables (depending on OS and tune), Adaptive Spark does work.

Personally I usually drop my spark ~2 degrees if my knock sensors show consistent KR at WOT.

Ultimately a dyno session or two will get you as close to ideal spark and AFR as possible.

[Mr. P.]

The knock sensors will most of the time protect you from a boneheaded tuning mistake, but not always. AFA engine damage, it's all a matter of how much torque you are demanding, on a NA motor you might not sweat an occasional 1-2 degrees of KR, but if you are in the 150+ Kpa range I wouldn't want to see any at all, also remember that IATs and fuel quality have a lot to do with guestimating any kind of detonation threshold.

The more realistic issue is that when the PCM panics because it sees KR then you are going to be running off the low-octane spark table, bye-bye economy.

Experiments have shown that best performance and mileage is obtained well before knock occurs, the goal is to shoot for "minimum best timing", I will stop here, because I am sure it's well covered on Google.

Mr. P.