What is stealing my timing?

[ls1x2]

Looking for a little help here. Car is a 2009 CTS-V M6. Only changes since last tune is a cam swap and clutch. Motor had to come up, but shouldn't be related.

It's full bolt ons on flex fuel with a cam. The issue I'm seeing is timing just not adding up based on what I'm commanding. I've turned off most tables that pull timing with the exception of IAT. Hi/Lo octane tables are copied. Flex fuel you will see in the logs commanding a 5.5* advance. I am statically retarding cylinder #5 2-5* across the band due the knock sensors indicating it needed for whatever reason. Not rare on these cars from what I understand.

I was seeing 16-17* under boost when it should have been in the 19-21* range based on almost same tune with prior mods. It dropped down to about 13* when I made an adjustment to the IAT spark multiplier. Set it all to 1. Something I simply missed in the past.

6:51:43 in the attached log I get 12* advance total at 5600rpm. Should be 16* base + 5.4* flex fuel advance - 5* IAT retard. So about 16*. I'm obviously missing something. Logs attached. Appreciate any help.

S.hplS.hpt14.Layout.xml

[ls1x2]

Looking for a little help here. Car is a 2009 CTS-V M6. Only changes since last tune is a cam swap and clutch. Motor had to come up, but shouldn't be related.

It's full bolt ons on flex fuel with a cam. The issue I'm seeing is timing just not adding up based on what I'm commanding. I've turned off most tables that pull timing with the exception of IAT. Hi/Lo octane tables are copied. Flex fuel you will see in the logs commanding a 5.5* advance. I am statically retarding cylinder #5 2-5* across the band due the knock sensors indicating it needed for whatever reason. Not rare on these cars from what I understand.

I was seeing 16-17* under boost when it should have been in the 19-21* range based on almost same tune with prior mods. It dropped down to about 13* when I made an adjustment to the IAT spark multiplier. Set it all to 1. Something I simply missed in the past.

6:51:43 in the attached log I get 12* advance total at 5600rpm. Should be 16* base + 5.4* flex fuel advance - 5* IAT retard. So about 16*. I'm obviously missing something. Logs attached. Appreciate any help.

S.hplS.hpt14.Layout.xml

Anybody?

[IXR08]

post tune file

[ls1x2]

Those are 3 links at the bottom of the post. S.hpt is the tune file.

[IXR08]

Have u tried running the static table on cylinder 5 at 0, i understand it to be sometimes problematic. Also looking at your log at approximately 1:14.009 there is no knock retard on any of the cylinders but total knock retard is at 3.9 degrees. I also 0 out the piston slap table although that is not likely to effect your issue here. Also try set knock sensor initial level to 160 & min level to 125

Capture.JPG

[IXR08]

Also you are only at 68% ethanol percentage so the table in picture below will only give you timing advance based on ethanol percentage so you would need 100% ethanol so to get the full 6 degrees make it 1 from 50% upwards.

Capture1.JPG

[ls1x2]

If I set the static table for cylinder 5 lower it will knock. It's done that with every set of mods this car has had. No idea why. That 3.9* is the 4* statically commanded in that range for cylinder #5, isn't it? I don't know what the actual difference is between the "knock retard" PID and the "Total KR," But I think one shows the reaction to what the sensors sees, and the other includes commanded KR.

Don't those values make sense though for the ethanol blends? I'm not wanting full timing on e66. I was under the impression it does round up though, so it should have been using the 75% value. It shows that it's commanding 5.6* of flex fuel advance. 100% would be 6, and 75% 4.5 so not sure what is going on there honestly.

[IXR08]

Are you sure its true knock? or just what the logger is showing? try set knock sensor initial level to 160 & min level to 125 then reduce cylinder 5 to 0 degrees... I would also try swapping a plug & lead from another cylinder to see if it still knocks.

[ls1x2]

Are you sure its true knock? or just what the logger is showing? try set knock sensor initial level to 160 & min level to 125 then reduce cylinder 5 to 0 degrees... I would also try swapping a plug & lead from another cylinder to see if it still knocks.

I do not know for certain if it's real knock or not. It's done it as a bolt on car and after this camp swap. Plug swap has not mattered. New vale springs and pushrods has not mattered. GM commanded more timing than these cars can take from the factory. They all have KR. So strange.

I'm not too sure about desensitizing the knock sensors across the board. I know they are very sensitive on this car, but just doing one cylinder seemed safer. Prior to the cam swap this current problem did not exist. Mostly the only change is MAF airflow and Idle timing, unless I'm missing something. Attached is a tune file from the same setup, minus, clutch, and cam kit. It was seeing timing that made sense. 18-21 up top as commanded.


a-base from b4 cam.hpt