LT4 ZL1 1LE seeing KR but not seeing timing reduced

[Racerbox77]

2021 Camaro ZLE manual. Only mods are Kooks 2" long tubes with green cats and a Roto-fab intake. 93 octane. About 600ft above sea level.
I'm getting KR on the OE timing tables. I zeroed out the COT advance and tried pulling 2 degrees with no real change in KR. Also added 5 degrees to the SOI Base table in the higher cyl airmass areas then smoothed down OE by 4000 rpm. No noticeable change in KR.
I have the AF in the high 11's which is on the rich side for a DI engine but for now I just want it on the safe side. OE was 10.0 after the mods!
Whats got me stumped is when I see KR there is no timing pulled. On Gen 3 and 4 when I log KR it will show that amount subtracted from total advance. I've desensitized the kr sensors about 25%. Raised the VVT in the higher levels and smoothed to OE without any noticeable change.

I've attached a log and the tune file. Car runs great but based on the logs its got more in it. Hopefully

AF was not logged on this day but like I said its in the high 11's.
21_Camaro_zl1e.hpt
21-11-23 10-56-40.hpl

[Racerbox77]

93 Octane, 11.7 afr stock pulley.
Timing is @ 17 and knock is showing 5 degrees so it's actually at 12 just not showing actual?
During the same drive/log sometimes it would only show 1 degree of knock. Anyone seen this before?

[TriPinTaZ]

Which Rotofab intake? Regular or Big Gulp?

Stock LT4's with headers are going to show "false knock" at times and that looks to be your case. You can usually spot false knock when the ECU isn't actually pulling much timing at all. I made a few changes to see if it helps. Reducing timing moves the torque estimation down which could actually result in incorrect torque calculations. Depending on how much you lower timing(which lowers torque) then add airmass(by adding mods and changing the MAF) it can throw off the correlations. I think there are pieces we still cannot see in HPTuners that relate to this. But the VVE is tied to it which is why I added 5% to your VVE in the WOT area.


I will say there are a couple other things in my experience that exacerbate the issue such as Shell branded gas and some non top tier fuels or excessive amounts of oil getting into the blower/intake.

Load this file and see if it helps. You should bring the enrichment in stronger as the blower is going into peak torque. That is why you see I changed your PE table. Also, you had a spike in your MAF around every time the knock started. This could be a contributor as well. I smoothed it out a little but not too much as to change any fueling drastically.


edited_21_Camaro_zl1e.hpt

[Racerbox77]

Which Rotofab intake? Regular or Big Gulp?

Stock LT4's with headers are going to show "false knock" at times and that looks to be your case. You can usually spot false knock when the ECU isn't actually pulling much timing at all. I made a few changes to see if it helps. Reducing timing moves the torque estimation down which could actually result in incorrect torque calculations. Depending on how much you lower timing(which lowers torque) then add airmass(by adding mods and changing the MAF) it can throw off the correlations. I think there are pieces we still cannot see in HPTuners that relate to this. But the VVE is tied to it which is why I added 5% to your VVE in the WOT area.


I will say there are a couple other things in my experience that exacerbate the issue such as Shell branded gas and some non top tier fuels or excessive amounts of oil getting into the blower/intake.

Load this file and see if it helps. You should bring the enrichment in stronger as the blower is going into peak torque. That is why you see I changed your PE table. Also, you had a spike in your MAF around every time the knock started. This could be a contributor as well. I smoothed it out a little but not too much as to change any fueling drastically.


edited_21_Camaro_zl1e.hpt

Thanks Tri!
It has a Regular Roto Fab intake. I'm curious why you added back the 2 or so degrees in COT timing but then took out 1 or so in the High Octane table? I see you raised the knock threshold a little more than I had it. I was worried about dumbing them down too much to start with.
Still think its strange the KR is showing 5 or so but the total timing is not moving.
Ill give this a try and report back.

[TriPinTaZ]

I prefer to let Power Enrichment add extra timing so that it only comes in when you're in PE mode just like the OEM strategy. I like to keep as many OEM strategies in place as possible. The car just drives better in my opinion.

KR triggering but timing not dropping means it started to pull a half a degree but KR stopped so it didnt keep going. It also could be false knock which can happen when your torque or airflow model is off. There are a bunch of threads about it.