[Nothubertjfarnsworth]

A split second later it shows 6 degrees in the burst knock pid fwiw. I'll have a look at those tables and see if I can make sense of it.

so it is burst knock for sure, then. that delay threw me off.

 

[evsnova74]

Ok I finally took the time to post on hpt forum so I can post some actual logs.

Identifying false knock?

Long time lurker, first time poster. Car: 2005 GTO, 6.0l LS2 Mods: Fast102 intake, Kooks stepped headers Fuel: Shell 93 TT (only) Wideband: idk, the AEM one with CANBUS I've been dipping my toe into tuning the last few months, dialing in VE and MAF using stft, and using an AEM wb to do...

forum.hptuners.com

 

[Nothubertjfarnsworth]

first response? DiSaBLe BuRsT KAnoCK.

 

[evsnova74]

first response? DiSaBLe BuRsT KAnoCK.

Meh, I just wanted a place to post logs.

 

[evsnova74]

I did take a look at the burst knock cylairdelta table and didn't get why it maxes out at .032g. I checked the log and cylinder airmass is showing figures in tenths so it's probably not referencing that. My IAT's never get above 100, ECT doesn't seem like anything to worry about, but I found the RPM multiplier table interesting in that the highest values are between 1500 and 2500. I'm going to have to learn more before messing with these.

 

[evsnova74]

it started to pull timing when dyn air went up. it sounds kinda like burst knock. so the ECM might be anticipating knock because of the sudden change in airflow. so it pulls timing.

From what I'm reading, you were right on the money here. It's pulling timing early in a run in anticipation of a knock so that it doesn't actually get any, kinda like "flinching". I was just going to ignore it but seeing as how it's not real knock, I figure why not play around with it and see what it does. So I've shifted the base vs cylairdelta over a couple columns, and pulled 10% out of the mult vs rpm table, see what if any differences that shows.

 

[evsnova74]

Now I'm still getting kr but not registering any burst knock retard. Pulled 5 degrees out of the base table and same thing. Logs posted on hpt:

Identifying false knock?

Long time lurker, first time poster. Car: 2005 GTO, 6.0l LS2 Mods: Fast102 intake, Kooks stepped headers Fuel: Shell 93 TT (only) Wideband: idk, the AEM one with CANBUS I've been dipping my toe into tuning the last few months, dialing in VE and MAF using stft, and using an AEM wb to do...

forum.hptuners.com

 

[evsnova74]

Well I did end up disabling burst knock as a test and left 5 degrees out for good measure, still getting a few degrees of kr:

Identifying false knock?

Long time lurker, first time poster. Car: 2005 GTO, 6.0l LS2 Mods: Fast102 intake, Kooks stepped headers Fuel: Shell 93 TT (only) Wideband: idk, the AEM one with CANBUS I've been dipping my toe into tuning the last few months, dialing in VE and MAF using stft, and using an AEM wb to do...

forum.hptuners.com

Which, by desensitizing it like I did I already kinda disabled it. Seems to me this can't be true knock. So what, this is potentially caused by say the headers hitting the steering coupler during turns or some other kind of external thing tricking the sensors into thinking it's getting spark knock? How would a guy ever go about testing for that?

 

[Nothubertjfarnsworth]

is your knock still happening just under changes in airflow? you could try messing with the transient mode tables and see what happens.

you can also adjust the knock sensor threshold levels.

 

[evsnova74]

Just now getting a chance to really look at these logs. At first I thought it wasn't correlated because in the last log I had a rise in airmass in 1st gear but only got the kr in 2nd. But looking at the actual numbers it looked like I was getting the kr at around .42g of airmass. Then I checked the previous log and was starting to get confirmation of .42g, but immediately after a gear change I got 1.7 degrees of kr at only .35g of airmass. Then to really blow that theory out of the water, later in the log I got 1.4 degrees of kr during a shift when the airmass went down. There's nothing apparent to me in the chart that correlates with it.

I'll still try to mess with some more things in the knock section. At this point it's purely educational, I'm not worried about this like it's some huge problem.

 

[Sacrifice]

IAT will play into KR as well. Idk how to feasibly tune it on the road. I kept pulling some out and it would still happen. I think it is what it is.

 

[Nothubertjfarnsworth]

IAT will play into KR as well. Idk how to feasibly tune it on the road. I kept pulling some out and it would still happen. I think it is what it is.

interesting.

 

[evsnova74]

I'm really starting to wonder about some of the shit I see on hpt. I read a post where a guy said the ls2 has such high compression that it's on the ragged edge of knock off the factory floor. The someone else said that for some unknown reason the scanner picks up knock within 15 minutes of a new flash, so wait 15 minutes before trying to log kr. I know I'm in no position to call bs, but I started logging bs and was getting a few degrees of bs retard from these posts.

I might try to take a little more timing out at some point to see if I'm still getting any kr, but I think my next step is to visually inspect any areas where contact may be occurring. Like the header and steering rack for instance.

 

[Nothubertjfarnsworth]

I'm really starting to wonder about some of the shit I see on hpt. I read a post where a guy said the ls2 has such high compression that it's on the ragged edge of knock off the factory floor. The someone else said that for some unknown reason the scanner picks up knock within 15 minutes of a new flash, so wait 15 minutes before trying to log kr. I know I'm in no position to call bs, but I started logging bs and was getting a few degrees of bs retard from these posts.

I might try to take a little more timing out at some point to see if I'm still getting any kr, but I think my next step is to visually inspect any areas where contact may be occurring. Like the header and steering rack for instance.

that is weird. i've never noticed kr after flashing. the ls2 doesn't have THAT much compression. 10.9:1 is nothing these days.

i think once you've exhausted the burst knock and over-sensitivity theories, that physical noise is definitely a next step. the motor torquing over when you punch the gas and noise being transmitted through the block could very well cause it.

not sure you should keep pulling timing. as long as the gas is quality stuff, and you have no mechanical source of knock (say hot spots in the cylinders for whatever reason or clogged injectors making you run lean), there's no reason you shouldn't be able to have 24-25 degrees of advance at WOT with 93 octane.

 

[Sacrifice]

I see no reason to go lower than stock on a near stock engine

 

[evsnova74]

The intent was to pull the timing, still see "knock", confirm that it's fake and add the timing back in, resume ignoring it.

 

[Nothubertjfarnsworth]

sounds like you're on top of this stuff then.

 

[evsnova74]

sounds like you're on top of this stuff then.

That's it I'm leaving the site.



















(but seriously, it sure doesn't feel like I am, I feel like I'm grasping at straws in the dark. I was just clarifying that when I say pull timing, I mean temporarily as I'm still not fully convinced that it's genuine knock)

 

[evsnova74]

I'm also going to log the kr in the individual cylinders, again, more straw grasping.

 

[Nothubertjfarnsworth]

That's it I'm leaving the site.

yeah, i mean, you don't NEED us or anything.