DavidNJ

Knock control puts one or two microphones alongside the block. 'Knock' is picked up by the vibrations and the ECU can retard the ignition to alleviate the problem while needed.

The ECU can detect which cylinder is knocking because it knows which cylinder just fired. That way it can just change the affected cylinder. Because of different cooling in the block and head, nuances in the intake and exhaust manifolds, and minor production variances each cylinder can be different.

However, not all ECUs support that feature. As far as I can tell Haltech supports one retard for all cylinders. Life/Syvecs and AEM Infinity (at least 7-series) support individual cylinders.

It probably has the most impact in pump gas forced induction engines which have their boost limited by the octane level of the fuel. NA engines could be affected. With super high octane (e.g. E85) or water/methanol injection the issue is reduced in importance.

J&S Electronics makes units that just do individual knock control. They have an article in their tech section that explains it: http://www.jandssafeguard.com/index.html.

Do you use knock control and individual cylinder knock control?

flanders

I'm NA with E85 so not knock limited, just using stock settings in kpro.

Mijae007

This feature isn't typically needed for a properly tuned map. My cylinder trims were always set to 0 when n/a and is also set to 0 now making 515whp with NO knock counts. My 91 pump turbo map was also tuned without touching any cylinder trims. If you're knocking, your tuner should be able to tune it out by retarding timing or adding more fuel where it occurs. I always felt cylinder trims was a bandaid in eliminating knock, unless you have a mechanical issue causing knock in a specific cylinder but in that case it would make sense to repair the problem as opposed to masking it by pulling out timing.