so i finally was able to get a datalog when my car "knocked". how can i tell why it knocked?

and what can i change to make that not happen?



thanks for any help or insight!

 

you need to post up a/f as well, can you make the knock count come by consistently?

by looking at the a/f on the top, if its really showing 14.7 at full throttle at 7800, you might have a problem there.

 

AF shows 14.7 on my KPRO because I don't have a wideband, I have a/f from the dyno printout, it goes to 11.5 from 7k-7.7k

 

I don't see anything in the graph to show when the knock count occurred. If you add it to the graph, and see that the knock count consistently occurs near the same RPM at full throttle, then you can try reducing timing there a couple degrees to see if it goes away. However, if you just have 1 or 2 knock counts showing up on your datalogs at random times, I'd say they are not real knocks. I get ghost knock on my NA AP2 even when it's totally stock.

 

hm, yea i dont really know what i'm looking at/for, so any insight would be good

does this help at all? or is there anyway to tell ghost knock from real knock?



i'm trying to show that in the first pic, there was no knock, and the 2nd pic there was, the knock count went to 3 after the first dyno, up 2 to 5 the next run, and then up 1 to 6 after the 3rd.

these screenshots are from the first dyno run, let me see when the others occured

 

2nd dyno run knocked around 7500 and 7750, 3rd dyno run around 7250

 

ok found this in kpro info "Knocking is caused by too much ignition advance and bad fuel."

so maybe i should remove a degree of timing from 7500-8000?

 

I would try reproducing the knock counts on the street by doing some WOT pulls in 3rd gear on the highway. If you can reproduce it, then remove 3 degrees from 7000 - 8200, and try reproducing it again using the same procedure. If the knock counts don't go away or get better, then I would write them off as ghost knock.

BTW, Does the K PRo say which cylinder it thinks is causing the knock counts like the FlashPro does?

 

no, kpro doesn't tell which cylinder, unlike flashpro, maybe that will be a feature eventually?

3 degrees? that's not too much ? (i don't have any idea, which is why i'm asking) or that's a large enough amount so that if it was really knocking it would most likely go away?

 

There's no danger in retarding timing by 3 degrees, but if ignition timing is causing knock, then 3 degrees is significant enough that it should go down (or away). If you just retard timing by 1 degree, it might not be enough of a change to make a difference in knock.