Well, suggested by tephra I post this log of an 88840017 EDM Evo IX with the *old* V5 mod. If you look in "AFR IDC" tab you can see a weird AFR situation: AFR Target (that is AFRMAP in evoscan) is stable during the pull, while WB AFR goes crazy... 18+ AFR in WOT over 6000 RPM

The problem was related to V5, now should be correct so don't mind about the origin. The strangeness is the total absence of knock.

Before the log I did some pulls (2 or 3) and at 6000 rpm it seemed like hitting a wall; but CEL flash didn't light, so I suppose no knock during pulls.

Now, I have logged in the past some knocks over 6000 while playing with timing and my knock sensor does work (I get some knock during street use).

But how can it be possible a 0 count in this situation? Does someone experienced something similar?

 

i think its pretty interesting - interesting that your loads stayed high as well.

 

At first I thought maybe your wideband sensor was going crazy but your IDC's confirm that in fact it did lean out. Is it possible that it did lean out but not as much as the sensor would indicate. Maybe it leaned out to 13 or 14 or something like that.

As for being super lean and not getting knock, that is interesting. I have run the car pretty lean at that RPM and not had any knock problems, but I'm talking like 12.5 ---- not 18+

 

Don't quote me on this, but I think the speed of the flame front dramatically decrease away from a peak speed that occurs somewhere around 12.5-13.2 for forced induction. I remember reading something somewhere about it.

Either going richer or leaner slows the burn and loses a lot of power. I'm guessing that you going so lean simply lost so much power that it wasn't enough to cause any detonation.