2015 GT TT Knock Issue

I have been having a knock retard issue for some time and still can't seem to figure it out. I believe I have the MAF within acceptable range but please let me know if you see anything. I am only running wastegate boost (5.5 by my boost gauge) and it seems to always pull timing after about 4,000 RPM. The car is running on 93 only but I can't see that being the issue for such low boost. Could it be my IAT is to high causing it to pull? Any advice is appreciated.

SS of pulled timing
Attachment 101070


Full Log and current tune
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I would say try increasing your tipin retard. I suggest changing hold events(ecm 44613) at 3000 from 16 to 32. Look for the timing spike right after you get into the throttle to reduce or go away completely. Increase or decrease to where timing is flat immediately after a tip in event, while load is still increasing as boost builds. You don't want it to long that it prevents the knock advance from coming on, but you don't want it coming back in too soon as the load is building very quickly.

Log spark source to confirm thats what that spike of timing is.

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Originally Posted by murfie

I would say try increasing your tipin retard. I suggest changing hold events(ecm 44613) at 3000 from 16 to 32. Look for the timing spike right after you get into the throttle to reduce or go away completely. Increase or decrease to where timing is flat immediately after a tip in event, while load is still increasing as boost builds. You don't want it to long that it prevents the knock advance from coming on, but you don't want it coming back in too soon as the load is building very quickly.

Log spark source to confirm thats what that spike of timing is.

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Sorry I originally uploaded the wrong log and screen shot I am not sure if you read this before I editted it. Could you please take a look at the new one i posted, sorry for the confusion. The correct log has spark source logged

Need to be able to see which mapped points you're running in. You've only captured a few.

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Originally Posted by smokeshow

Need to be able to see which mapped points you're running in. You've only captured a few.

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I believe every map point is listed. If you read this before I changed the log that could be why only a few show i uploaded the wrong log originally

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Originally Posted by imrex613

I believe every map point is listed. If you read this before I changed the log that could be why only a few show i uploaded the wrong log originally

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Yep I see it now. It honestly doesn't look that bad. Either pull a couple degrees of spark back in that knock range or retard the intake camshaft a couple degrees.

Have you tried an octane booster like boostane? Your 93 might just be junk.

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Originally Posted by smokeshow

Yep I see it now. It honestly doesn't look that bad. Either pull a couple degrees of spark back in that knock range or retard the intake camshaft a couple degrees.

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I tried pulling the spark to around 15 but it seems even that is to much, maybe I need to go further? Maybe this setup really doesn't like ANY timing on 93? Are you saying to retard my Intake Valve Opening angle? [ecm 38150]

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Originally Posted by murfie

Have you tried an octane booster like boostane? Your 93 might just be junk.

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I have not my original plan was once I actually make it to the drag strip to run race gas to help prevent any kind of knock but I assumed at 5.5 psi I would have none. If you guys don't see any issues or mistakes then maybe this car really just doesn't like timing on the 93. e85 is an option but personally I would prefer not to use that just based on convenience of stations around me. Also do you think I should still incrase my tipin retard with the updated log?

Fuel is not an issue I can shove 25 degrees in on 93 with 10psi of boost - your problem is somewhere else.

I'd say it's mechanical, seen this before way too many times. What kit? ON3?

P.S. Might be hard to swallow for you but your MAF curve leaves a lot to be desired.

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Originally Posted by veeefour

Fuel is not an issue I can shove 25 degrees in on 93 with 10psi of boost - your problem is somewhere else.

I'd say it's mechanical, seen this before way too many times. What kit? ON3?

P.S. Might be hard to swallow for you but your MAF curve leaves a lot to be desired.

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What have you seen be the cause when you saw this issue before? It's a custom low mount kit with precision 6266 turbos mounted same way as hellions are.

Stock headers?

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Originally Posted by veeefour

Stock headers?

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yep stock headers still

Need to see some pics, hot side

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Originally Posted by veeefour

Need to see some pics, hot side

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This last photo shows where my MAF current is moved to in red don't have a updated picture of it
Attachment 101084

Ok this actually have a decent header transition - those are big turbos should have a bigger 4 to 1 headers, stock might choke with that turbo.
Turbos shouldn't be tilted like that tho. MAF placement is not an issue - too many false "clocking" theories.

But still something is up - mega knock poping up in the middle of the run. Tuned to many turbos this doesn't look right. Don't have much time to dig in your tune atm.

OP disable misfire monitor - useless with turbo. Check those T3/T4 flanges for leaks. Disable IRMC - usless with turbo.
Disable half of MP's as you don't want to use IMRC.
+15/+15 for cam angles in OP is way too much, this won't work with turbo
Reduce your fuel enrichment rate - 0,4-0,5 lambda is too much. Also don't start with 0,76 AFR ratio.

Few more but don't have time to ding into your tune.


All of this tells me you have rich detonation or an exhaust leak.

Quote:

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Originally Posted by veeefour

OP disable misfire monitor - useless with turbo. Check those T3/T4 flanges for leaks. Disable IRMC - usless with turbo.
Disable half of MP's as you don't want to use IMRC.
+15/+15 for cam angles in OP is way too much, this won't work with turbo
Reduce your fuel enrichment rate - 0,4-0,5 lambda is too much. Also don't start with 0,76 AFR ratio.

Few more but don't have time to ding into your tune.


All of this tells me you have rich detonation or an exhaust leak.

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Since you mention exhaust a thought came into my head. My wastegates are very close to the floorboards, do you think there's a chance that under acceleration the motor shifts and they are tapping causing false knock? I know there is no leak because I just checked for that

So i reset the VCT tables back to stock and it did seem to help but it still knocked. I changed tipin at 3k RPM to 32 and did a 3rd gear pull. This log is of that at 7psi it seems to have made it worse so I reset it back to what it was. Is it possible maybe my gas is indeed just junk? I know most people lock out IMRC and disable but mine seems to be working properly so I am assuming that would not cause knock? I am open to any advice as this is driving me nuts.

Log of pull
Attachment 101094

Your driver demand table/ torque model is not setup to help the TCC lockup well with a turbo car. TCC could be chattering being picked up by the knock sensors.

If at .8 load you see 280ftlb, at 1.6 load you should see ~560ftlbs, to get the right line pressures applied to the clutches and TCC. you are seeing 413ftlb(stock). Fill out your maximum load tables under SD.

Quote:

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Originally Posted by murfie

Your driver demand table/ torque model is not setup to help the TCC lockup well with a turbo car. TCC could be chattering being picked up by the knock sensors.

If at .8 load you see 280ftlb, at 1.6 load you should see ~560ftlbs, to get the right line pressures applied to the clutches and TCC. you are seeing 413ftlb(stock). Fill out your maximum load tables under SD.

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After taking murfie's advice here I think I am finally heading in the right direction with this. My Maximum Load tables under speed density were still all at the factory settings as he stated. After completing them I loaded the tune and took the car for a drive. It feels to be stronger under boost although I cant confirm if there is a difference. Before on wastegate I would see about 4.7 psi max on the gauge now its 5.1. On my first stage of boost which before was 7 psi max I now see 7.7. I am assuming this is due to things working properly now as I did not touch either of these. on wastegate it is not pulling anywhere near as much timing, little to nothing. On the first stage it still pulls timing but no where near as bad as previously.

Below I have attached logs of a quick 5psi pull, 7.7psi pull and then one with a pull from each stage. I still am not taking the car to redline as I am still checking things over but it seems I am headed in the right direction. I did order a bottle of boostane to try to see if I could reduce knock 100%. Open to any advice or discussion of errors you see in these logs, thanks again!

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