I just Datalogged my car with DataMaster and found a fairly high knock count. It is only at mid RPM(3400) any ideas what it could be? I have a log I can Email you if you want to see it.

Thanks for looking

 

Assuming this isn't actual detonation... I have seen this happen on cars with modified exhaust systems (E.g. headers). My guess is that with certain exhaust modifications there is some sort of resonance in the exhaust that is picked up by the knock sensors. You can see it as very consistent knock retard at a specific engine speed. Many people install the LT4 knock module to reduce the sensitivity of the knock sensors on LT1 vehicles.

A loose exhaust component that is rattling could also cause this.

 

Thanks. I already have a LT4 knock module, but it could be the exhaust I will try octaine boost and adjust the RR. If its the exhaust I will get rid of the EGR stuff.

 

If I read your post correctly, you have only datalogged a high knock count. Have you also recorded any actual knock retard? The two do not necessarily go hand-in-hand. I've seen many data logs where increasing knock count does not trigger knock retard, and many cases where high knock retard occurs when the knock count is standing still.

And hopefully you are aware that the knock count field is constantly incrementing, reaches the limit of the field and then resets to zero. The actual number in the knock count field is really not very important, its when is it changing and how fast is it changing? Is is very normal for it to increment by a few thousand counts on startup for example, when there is no knock retard being used.

Vince.... do you know the algorithm used to increment knock count? That's something I've been looking for.

 

I believe "knock count" is a numeric representation of the amount of noise being picked up by the knock sensors. In datalogging a customer's car, I found while driving, when there was a steady amount of detonation the knock count was x, but stayed at x, but if the level increased, x went up.

 

I guess what I'm saying is that when i see the knockcount go up i also get up to 7.1 deg of retard, sometimes it's as low as 0.1 deg. There are also times when the count goes up but no retard. I've slowed the datalog right down to see this.
If you would like to see it I can Email it to you.
Thanks

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