Little Help Interpreting Logs - TQ Modeling - 2018 ZL1

I could use a little help interpreting this log. I believe I'm logging the correct information, but I'm not seeing exactly what I expected. Specifically around these charts:

predicted engine tq vs delivered eng tq vs max eng tq. I was expecting to see the predicted higher than the max now that I've got full timing in it with dialed in afr.

Accel pedal % vs throttle %. Does this indicated the throttle not opening all the way? These are the non-sae sensor values. Additional throttle PID's are in the table view. My understanding was these 2 show if the ecm is shutting the blade.

Is anything pointing to what is causing this KR? I've got very hard time believing it's real with the stock timing map, 55* air, stock boost, and some water/meth spraying.




This was the test run to get afr dialed back in after adding meth injection. I've yet to move the sensor. That will happen before I get back to tuning. IAT's couldn't be anywhere near as high as indicated.

Appreciate any tips. Still learning gen5. I've got some general guidelines for starting on the tq modeling, but I'd like to fully understand the logs first.

Attachment 95801

Attachment 95802

What are your mods? Log shows 12lbs of boost which isnt stock. Post your tune.

It actually is the stock pulley. Only thing I did was modify the bypass vlave.

Stainless works 2" headers with !cats.
Rotofab cai
Snow methanol


Tune is posted above.

What's your Lambda value at WOT? I finally stopped seeing KR at 20* with stock Knock sensor values after I leaned it out to .86 actual.

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Originally Posted by HeavyChevy305

What's your Lambda value at WOT? I finally stopped seeing KR at 20* with stock Knock sensor values after I leaned it out to .86 actual.

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.82. That's interesting. I've read similar but not a consensus.

Yes bump your lambda to .84 and see if it clears the knock. I was getting some knock at .82 and leaning it out a bit fixed that.

.85 is considered safe on a LT4

Will be leaning it out to see what happens with the KR. What about the throttle opening and predicted tq?

I leaned mine out to .85 and seems to like it. For a few pulls it was .87 and seemed fine with that but not something I would do full time. Amazing how lean direct injection can run over port injection.

I dynoed a 2019 like you mods 7 speed standard and it made 622rwhp on pump gas

I added flex fuel over the weekend and bumped the timing up. This car just rips. No traction even at 80mph

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Originally Posted by jsbaugh

I added flex fuel over the weekend and bumped the timing up. This car just rips. No traction even at 80mph

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How much total timing? Did you do the DSX low side as well?

My timing is around 22 but that is only on e30. I?m limited to about e40 on the stock fuel system. With just pump gas I can only run around 18 degrees of timing before I get some knock.

So I went ahead and leaned it out to .85-.86. This log is closer to .84 in reality. Leaning it out to .86 didn't change much. A few questions if anyone cares to answer. I also desensitized the knock sensors a bit. Notes of changes:

m2 = leaned out to .85 lambda
decreased knock sensor levels some
lowered kr attack rate as well
ect vs retard changes
5% add to peak engine tq above 2k rpm

driver demnd last 2 rows x10% then last 4 x10% then last 5 by 10%
copied driver deman A to all others
3% added to peak tq
on cutoff tab disabled "use predicted tq"
disabled catalyst test on exhaust under eng diag
desired eng coolant temp set to 185 under fans

m3 = maf to get to .86 lambda


1) Is the tq number recorded by the ecm a reflection of reality? I'd say I'm missing 100 ft-lb in that case. Surely this setup is 600+. 2" Headers, cai, single m15 meth, !cats. Show about 11-12psi.

2) There are 2 pulls in this log. On the 2nd I see the throttle shut from 89 to 73. I see "predicted eng tq cmd" being flat as "max eng tq" takes a nosedive. Not sure precisely where that indicates a problem. It stole my timing as well. It didn't do on the pull right before. WTF? Car just got a little hotter. :doh: It was consistently doing it the next few pulls with more heat in the engine.

3) Any thoughts on the MAT? My IAT2 stays steady or decreases through the run, but ECT climbs fast, and MAT follows. Should I even care? On any other car I'd read the sensors showing IAT with meth at 68* and ECT not even going over 205* and not pull any timing at all. Considering not pulling anything on IAT until 190.

Appreciate any help. Log and tune posted below.

Attachment 96149

Attachment 96150

Did you adjust the VVE tables accordingly already? With your mods you shouldn't have to touch your Peak Torque or DD tables at all.

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Originally Posted by HeavyChevy305

Did you adjust the VVE tables accordingly already? With your mods you shouldn't have to touch your Peak Torque or DD tables at all.

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Nope. I realized after some more reading that I've missed a step. Haven't found a guide that I understand about VVE yet though.