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What does Knock Count Global mean?


Tim D

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I thought I understood what Knock Count Global meant but after reviewing my datalog, I don't understand it. 

In my log file, I have Knock Threshold which I believe is the same as Knock Target in the tune.

The help file says:

Knock Count Global - The total number of times knock level has exceeded the knock target for all cylinders.

Does this mean, Knock Count Global increments whenever ALL cylinders simultaneously exceed Knock Threshold?

or maybe, Knock Count Global increments whenever ANY cylinder exceeds Knock Threshold?

I understand that Knock is only interpreted (and Knk I Trim activated) if system is active (i.e. not inhibited by any lockouts)

Please can someone explain what events have to take place for Knock Count Global to increment?

Thanks in advance.

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Thank you for the speedy reply, I'm still confused though.

I should have included my tune and log to help explain:

https://drive.google.com/file/d/1CtbSuLON4Rc5y7WZJKokeaEF8vvMiYRf/view?usp=sharing

https://drive.google.com/file/d/18GwVXLmhthmeB2o6udd0pL4r_3_TkMFi/view?usp=sharing

 

At time 2:41:900 Knk Level Cyl 1 exceeded Knock Threshold resulting in Cyl1 Knk I-Trim removing 5 degrees of timing and Knock Count Global incrementing to 1. This is what I expected.

But, at time 5:33:845 Knk Level Cyl 1 did not appear to exceeded Knock Threshold but Cyl1 Knk I-Trim removed 5 degrees of timing (indicating that Knock Threshold had been exceeded - perhaps a Knock event was too quick for the logging rate?). Knock Count Global did not increment.  There are a fw occurences of this in the log file.

I don't think there's any other trims that are influencing this.

Why doesn't Knock Count Global increment on these other Cyl Knk I-Trim events?  

Please can you help?

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13 minutes ago, Tim D said:

But, at time 5:33:845 Knk Level Cyl 1 did not appear to exceeded Knock Threshold but Cyl1 Knk I-Trim removed 5 degrees of timing (indicating that Knock Threshold had been exceeded - perhaps a Knock event was too quick for the logging rate?). Knock Count Global did not increment.  There are a fw occurences of this in the log file.

The retard is just be because you passed through the same cell in your knock trim table again that already had the 5 deg retard from the last knock event.  That retard will stay saved in that table until either you have driven long enough in that cell with no knock detected that it advances back again - or until next power up when it will clear the trim tables.

The count doesnt increment because there hasnt been any knock detected.    

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I would never have worked that out - thanks again for the speedy response Adam!
I had also misinterpreted how timing is re-introduced. So for an Advance Delay of 1.0 s and an Advance Rate of 0.5 degrees/sec, 5 degrees of timing is restored after 11 s providing you stay in that cell. 
My datalog was from a 10 minute track session and the 9 knock events were mostly around 5500 rpm which is around peak torque, suggesting it was probably real knock?

This is a great forum!!

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I would say yes it is most likely actual knock.  Track or circuit racing is going to be relatively high duty cycle at high load and knock can happen the longer you run the car hard.  
 

If you want to see if it gets better, try retarding ignition in the particular cylinder 2 degrees in that region and add 2-3% fuel on that cylinder in that region.  If you run another track event in similar weather and it happens less, then you had some knock there, and pulling 2 deg all the times is better than 5 degrees more of less all of the time.  Not that one would be making power knocking anyway. 

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