I've made a thread about this on 3Si but didn't get much attention. I've tried disconnecting the NB02's and tuning it out so I have full control over AFR but I've come accross a problem.

Under low RPM/high load it knocks like crazy even with a sane AFR and a couple of degrees timing pulled. If I plug them back in and go to stock tune (leaner and more timing) it may get a few counts of knock but nothing like with them disconnected.

I got better mileage with them disconnected and liked having control over the entire map but can't figure out what is causing the knock when I disconnect the NBO2s. Any ideas?