HELP! Twin Turbo C6Z has some knock issues

[kjlindgr]

Hey all. I've got a twin turbo C6 ZO6 with turbos. Has a ID1000 injectors and an Aeromotive eliminator pump. It has good fuel and I pulled spark like crazy but am still having knock issues. The car is running on MAP alone, with the IAT coming from the stock MAF. These pulls were done with 93 octane pump gasoline.

Another thing that is irritating that I can't seem to fix is the lean tip-in (stomp) problem. It goes lean on stomp. I haven't adjusted the stomp items because I haven't really comprehended what I've been reading on the forum, but I'm all for altering these if it would help.

Here's an example of my stomp issue. I stab the gas, it goes lean, and it knocks before it gets into PE mode.

http://lh4.googleusercontent.com/-zsHjDt28b-Q/T6s1QTyrouI/AAAAAAAAHNU/CCo2zsd8Xjo/s800/stomp-1.jpg


Here's a snap of my knock issue. AFR's look good, timing is pretty low, but it starts knocking like crazy. You can see the initial stomp blip too. Not sure how to prevent this knock higher up in the RPM range.
http://lh4.googleusercontent.com/-YaA9afvp9xs/T6s1P84hL0I/AAAAAAAAHNM/UijhQ4Xy5cM/s800/snap-3.jpg


I've got the full log file and tune file attached. Any help will be most appreciated!

[kjlindgr]

Another thing I noticed from looking at the graphs are that my LTFT on bank 2 is typically higher than that of bank 1. Sometimes what I would consider significantly higher. Any relevance here?

[kjlindgr]

Just another thought...not getting much feedback here, but hopefully someone will chime in soon. Could the blip in knock retard just be a burst knock condition? I still have the factory settings in here which might be playing havoc on things since this is a FI car and could be peaking the airflow condition to trigger burst knock. Thoughts?

[Redline Motorsports]

Well a couple things....first what year is this Z? Rear mount or front mount turbos?

Is the motor forged? What compression if so?

Are you using ID injector data?

What fuel?

What spark plugs?

You should be logging GM.KR not the pid you have..

You are "way" under sparked below 3000 period...that motor should take everybit of 20 degrees from the start of the pull. Also your too lean off the bottom as well.

You VE is also off as your commanded fueling isn't even close to your actual.

Start with this...

Howard

[kjlindgr]

Thanks for the response Howard!

The motor has a stock bottom end currently...so it's the standard 11:1 compression. I'm absolutely using the ID injector data supplied off their web site. I'm running 93 octane pump gas with NGK 4711 injectors. The car has front mounted turbos and is a 2007 ZO6. I've been working on smoothing the VE but as long as I'm a bit fat, I have been more concerned about the knocking issue. I'll switch my PID and try again.

When you say I'm a bit lean off the bottom, can you give me more explanation on that? I guess I'm not understanding that term.

Let me know if there's anything else that seems awry.

[kjlindgr]

I'm not seeing GM.KR as a supported PID, only GM.KNKRET on this E38 ECU. Is this going to be a problem?

[joecar]

Is the knock audible (that much knock retard would be audible)...?

[kjlindgr]

Not audible at all. The car does have wastegates vented to the atmosphere so it is a bit loud under boost, but knock is one of those things you always listen for and I don't hear anything out of the ordinary. According to the logs, it knocks on tip-in before any wastegate actuation has happened and it's definitely quite. It will buck during these blips as the timing makes it fall on it's face.

[Redline Motorsports]

The first thing you need to do is getting fueling in line. My reference to off the bottom was as soon as you went into WOT you where lean. I usually setup a car likc that at about 12.4 from 2K to about 3500 and then start bringing it down to about 11.5-11.7 to peak. Spark wise you can run close to stock ZO6 timing and then start ramping it down around 3500.

It also can be false if its at the same rpm everytime and with low spark. I don't recognize that plug but we use TR6 plugs from NGK. You should also have that pid for knock...

[kjlindgr]

Thanks for the help! Those NGK 4711 are TR6 plugs. I'll keep poking around with timing from +3500. If you have any maps you can share, I'd be most appreciative.

Thank you Howard!

[Redline Motorsports]

Make your own map.....I assume you have a good WB tied into EFIL and you have created a correction PID and logging the data?

[wesam]

If those are the plugs you are using
http://www.summitracing.com/parts/NGK-4711/

you are using the wrong plugs
those plugs has 9 heat range which is too cold for you application and with low timing i think it will fool

TR6 should be 6 heat range

[wesam]

this is the link for TR6
http://www.summitracing.com/parts/NGK-3689/

[kjlindgr]

I will try the different plugs. I have them on order. I still don't know if this would cause a lean condition. If the plugs didn't have enough heat in them, I would assume they would misfire and cause a rich condition on the O2 from the unburned fuel...no?

Here's another map with the GM.KR PID being mapped. You can see that right when I put the throttle into it, it jumps lean before smoothing out. Some of these I dumped fuel into the VE table just to see if I could over compensate for the lean condition.

Any thoughts? Should I be playing with the stomp tables in the dynamic fuel area?

http://lh5.googleusercontent.com/-faNQi3QninM/T7ENB6Z06dI/AAAAAAAAHNs/4e9VTJREP9g/s800/stomp4.png