Delivered Engine Tq 456 lb.ft/Rear wheel Tq 646 lb.ft

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2006 Corvette, LS2, E85 flex fuel, E-Force SC, 10 lbs of boost, PRC heads, 6L80E stock transmission. Dynojet numbers are: 682 hp @ 6,150 rpm and Max torque is 645 ft lbs @ 4,760 rpm. Delivered Engine Torque reads 456 ft lbs @ 4,760 rpm but should read in the neighborhood of 745 ft lbs. My tune is scaled (E38) because of the ID1050X injectors. I believe the scaled tune could be the reason for my low Delivered Engine Torque reading of 456 ft lbs. What do I need to do in order to bring my Delivered Engine Torque more in line with where it should read (in the neighborhood of 745 ft lbs,) ?

[hjtrbo]

Which scaling method did you use?

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The scaling method used doubled Stoich. I did not create the tune but had a professional tuner in my area tune for E85/flex fuel. Looking at what he created, I can see he doubled Stoich AFR.

[Ben Charles]

Tq model

[hjtrbo]

Airmass should still be inline. That's way to big of an adjustment needed. Your trans is at risk. I would take it back to the tuner.

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Trouble shifting at WOT is what triggered my review of the tune, data logging passes at the track, 1/4 mile, where I would hit the rev limiter for 2-3 shifts. My Corvette is not a daily driver but primarily used for 1/4 mile passes at Bandimere Speedway. I know my transmission is at risk with the Delivered Engine Torque reporting much lower than expected. Car runs quite well with the exception of WOT shifts. Was hoping there was something I could do to bring Delivered Engine Torque values within reason without taking it back to the tuner. Not sure he would be that helpful. Also, I am not sure what Ben meant by "tq model".

[hjtrbo]

You can adjust the torque model is what he was referring to. Yours is miles out. What's the highest cylinder airmass you see?

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Per my last data log with a DA of 7,400 feet and temp of 70*, Delivered Engine Torque reads 499 ft lbs, Cylinder Air reads 1.19 (g) at 5,500 rpm, 1st gear. Second gear peaks at Delivered Engine Torque of 465 lb.ft, with Cylinder airmass peaking at 1.17 (g). Thanks for the help.

[Ben Charles]

If you’re only hitting 1.17 load on a 10psi setup on a 6.0 the injectors tor data can’t be right either

[jxhunte]

I have attached my tune file. Perhaps this will help with solving my Delivered Engine Torque problem. This is my first attempt at adding a file to a thread so hopefully I've got everything right and it will appear and be accessible for review.

[jxhunte]

I have also attached a data log file of my last 1/4 mile pass at Bandimere. Not sure this will help but wanted to exercise my practice of attaching files to this forum thread.

[FASSTRUK]

Traction control settings seem active. and your limit is at 479 lb ft. That might be the issue

[hjtrbo]

Tune needs more work. Send it back to the tuner and get them to sort it out. They also don't know how to tune a trans. No torque management is active. I would not beat up on this till it's fixed.

Didn't look in detail but shift flare and O2 switching when WOT.

Screenshot 2022-10-05 115242.png

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I turn off traction control when running at the track so the 479 lb.ft limit under Traction Control System, Max Torque, should not be in play.

[Realizm]

Looks like some scaling problems still. I found a quick pull where my boost matches yours, which is around 5,000 rpm.

Yours shows an airmass of 1.13g and 50lb/min on the MAF, mine shows an airmass of 1.63g and 69lb/min on the MAF. Also which is weird, your MAP w/ calculated 8.3 psi boost (Manifold pressure - atmospheric) shows 139.7 kpa, mine at 8.0 lbs boost (LS9 MAP sensor, LS3 intake manifold on Procharged LS3) shows 160.6 kpa. Another thing is your absolute load is 317% there, that can't be right. Mine shows 171% which would seem closer to reality.

Screenshots below:
Yours:
c6-scaling.PNG

My screenshot at the same rpm/boost for comparison:
procharged-c6-gs.PNG

Some kind of scaling weirdness seems to be going on. I'm running the same injectors, ID1050X but on a 2011 C6 Grand Sport, not scaled due to the E38 ECU.

Anyone good at scaling know what he needs to change to get that sorted out? I did find this on Injector Dynamics' website regarding scaling, you may want to take a look to see if anything was missed. I'm at work and can't go through it bit by bit, but I could take a look later.

[[email protected]]

I heard from Greg Banish who suggested updating (increasing) the Virtual Torque Tables. Also, I contacted a tuner recommended by Circle D Transmissions who I will be working with to hopefully correct my engine and transmission tunes. Will let you know what I find out. I plan on dropping my 6L80E, shipping it off to Circle D for a Level 3 upgrade. Need my engine and transmission tunes in sync or the transmission upgrade will be worthless.

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Increased the Virtual Torque Tables by 30% (Airmass and MAP) which provided positive results, increasing Delivered Engine Torque from a high of 456 lb. ft to 640 lb. ft., in line with rear wheel torque found on my Dyno Sheet. I have not had an opportunity to fully test how this impacts 6L80E shift points as my Dayco No Slip Automatic Belt Tensioner failed upon my first WOT burst. However, a review of what data I was able to obtain indicates that this just may have solved my problem. Waiting on a new replacement tensioner. Once I have the new tensioner installed I can resume testing and will report back on my findings. I may increase the values of the VTT even more to better represent expected engine torque with rear wheel torque of 646 ft lbs.

[TheMechanic]

Can you post your fixed tune? Like to see what you did to fix it.

[Ben Charles]

Won’t be a bad thing to make TQ read little higher anyways

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Ben, Thank you and yes I plan on bumping the tables up another 10% and data logging the results (once I receive my replacement tensioner). TheMechanic, not sure posting up the tune would do you much good but I can explain what I did. In the Editor > Edit > Virtual Torque, I modified the Airmass and MAP Tables, increasing their value by 30%, interpolating between vertical bounds, extrapolating Coefficients, and Calculating Torque Tables. This procedure updated the Engine > Torque Model >Torque Coefficients > Airmass Based and MAP Based values. I set up the Virtual Torque Tables to reflect what my Data Log at WOT was telling me and that is: at 5600 rpm, cylinder air was 1.15g, MAP was 130 kpa, Spark was 17*, and torque was 488 lb ft. Actual rear wheel torque at that rpm is 645 lb ft. or approximately 30% greater than my Delivered Engine Torque reading of 488 lb ft. Increasing the Torque Tables by 30% placed me right at my rear wheel torque numbers but Delivered Engine Torque should actually be > than rear wheel torque numbers because of drive train loss, etc. When scaling the tune to accommodate Larger Injectors (double stoich method) for older E38 ECU's, this will leave the Delivered Engine Torque readings low and result in the TCU receiving bad data, under reported torque info, resulting in burning up the 6L80E. Delivered Engine Torque is just one of the parameters that can cook the 6L80E.