2016 Camaro SS manual torque management issues

[Tick]

I'm working on the tune of a 2016 Camaro SS with full bolt ons and a fairly large camshaft. We've made good power on the dyno, the car starts good, idles right on the desired idle rpm and overall drives great. I worked on the driver demand tables and was able to get the throttle to stay open at wot no problem and worked on the torque coefficient tables to get the car to idle like it should....

The one issue I have, is there is some timing retard upon take-off just under normal driving conditions in 1st gear and occasionally it will happen briefly after a shift. With very very light throttle this won't happen, and with an aggressive launch it doesn't seem to happen either. But 90% of the time taking off from a stop as normal it will pull out up to 20 or so degrees of timing for a couple of seconds and then finally the timing jumps to what it should be in the main table and the engine noticeably accelerates. When this happens, 'immediate engine torque source' logs 'Axle'. When the timing kicks in, 'Axle' will change to 'none'. Also, when this is happening immediate torque, predicted torque, and delivered torque are all reading about the same values. When timing kicks in, immediate torque jumps up along with delivered....but predicted stays the same. Depending on how you feather the throttle to get the car rolling, 'immediate engine torque source' might toggle between axle and none a few times. The timing line on the chart looks like complete garbage when just trying to get the car rolling....and while I wasn't logging all of the correct parameters, timing on the baseline logs we did before any mods look just as screwed up.

To be perfectly honest, I don't have much of a clue about how to utilize the Virtual Torque tool.... and I don't have a clue if this has anything to do with my issues. I'm not sure how a person would ever correctly calibrate all of that without spending weeks on it though. I have set up a histogram to log throttle desired airmass vs. actual airmass as error on the axis of the virtual torque tables and it doesn't seem to be far off in the region that im having these issues. I'm not sure if that's the right way to dial these tables in or not. I have also reduced the torque across the board up to a certain rpm as I would expect to be the case with an aggressive camshaft compared to stock and haven't seen any difference in my issue.


Also, I 'zeroed' out the camshaft timing everywhere except at the very top of the wot region and removed the huge block of camshaft retard that is present in the stock tune so the cam isn't moving around during this issue. Camshaft spark timing is zeroed out as well. The driver demand table is still stock at the throttle positions this all happens. Injector data is all stock and I have the fuel trims basically perfect where this is happening both with the maf and with the vve. This issue happens whether running just MAF, or running in Speed Density.

Any advice would be appreciated. Thanks

[TriPinTaZ]

I've chased this around myself. Still haven't solved it and those that know how to aren't talking about it on here. I suspect the solution is in the AIRFLOW > DYNAMIC > Prediction Coefficients area. There may also be a need for Virtual Torque adjustments (Torque Coefficients) but I have a stock cam and adjusting this made no difference. Driver Demand made no difference. VVE made no difference. That all being said, I know you are tuning a cammed car, but I think its more of an airflow thing rather than due to a cam change. I assume the car has ported pieces and full headers/exhaust etc.

So the area mentioned above is the last area that I haven't explored yet. I too get the Torque Management Advance pulling out a large amount of timing when taking off from a stop light. If I stay at 20-30% throttle it clears itself at around 2800 RPM. Or I can mash the gas down to 40%+ and the TMA shoots to 0. IF I drive like a grandpa, I don't have the problem either. Same symptoms but stock cam C7 Corvette.

Someone here knows, but they aren't telling.

[Tick]

I've chased this around myself. Still haven't solved it and those that know how to aren't talking about it on here. I suspect the solution is in the AIRFLOW > DYNAMIC > Prediction Coefficients area. There may also be a need for Virtual Torque adjustments (Torque Coefficients) but I have a stock cam and adjusting this made no difference. Driver Demand made no difference. VVE made no difference. That all being said, I know you are tuning a cammed car, but I think its more of an airflow thing rather than due to a cam change. I assume the car has ported pieces and full headers/exhaust etc.

So the area mentioned above is the last area that I haven't explored yet. I too get the Torque Management Advance pulling out a large amount of timing when taking off from a stop light. If I stay at 20-30% throttle it clears itself at around 2800 RPM. Or I can mash the gas down to 40%+ and the TMA shoots to 0. IF I drive like a grandpa, I don't have the problem either. Same symptoms but stock cam C7 Corvette.

Someone here knows, but they aren't telling.

Yep, 2800 rpm plus or minus a few and then its good.

[h2.4]

I'm not sure if this is similar to what you are having, but I noticed on a big cam car, If I overshot the Base Running Airflow while getting it to idle and take off better, I've had the Idle adaptive overspeed pull too much timing and give me issues. Like I said, not sure if this is what you're dealing with though.

[TriPinTaZ]

Yep, 2800 rpm plus or minus a few and then its good.

If you ever find a solution, please come back and share. I'd love to fix this. Right now I'm masking some of it by allowing the variable cam to retard 10 degrees and added VCP spark back in the area to increase the total spark value to offset the timing that Torque Management Advance is pulling out. But I still feel it when I drive.

[TriPinTaZ]

I'm not sure if this is similar to what you are having, but I noticed on a big cam car, If I overshot the Base Running Airflow while getting it to idle and take off better, I've had the Idle adaptive overspeed pull too much timing and give me issues. Like I said, not sure if this is what you're dealing with though.

Was this on an e92 ECU? I see "Dynamic Airflow Base Gain" under the Dynamic Airflow Prediction areas. But I haven't messed with this area yet. It looks like the table is referencing VE Zones from the VVE table.

[TriPinTaZ]

Tick, have you tried messing with these tables? They don't seem to really limit timing but look at right at 2800 in the lower Airmass area where the allowed minimum spark jumps quite a bit higher. I wonder if these tables play a role in TMA.

ENGINE > SPARK > ADVANCE > Minimum Spark > Base and Long Term

[Tick]

Tick, have you tried messing with these tables? They don't seem to really limit timing but look at right at 2800 in the lower Airmass area where the allowed minimum spark jumps quite a bit higher. I wonder if these tables play a role in TMA.

ENGINE > SPARK > ADVANCE > Minimum Spark > Base and Long Term

I see under the heading 'Spark Limiters' a table for Spark Minimum and a table for Spark Minimum Long. I haven't messed with those tables on this car. That may be a good way to band-aid the feel of the huge amount of timing kicking in when axle torque toggles off though... just make the minimum a value high enough that its just riding the minimum allowed spark when accelerating from a stop at the given airmass. The guy that owns the car works for us, so I'll see if he will drive the car one day later this week to play around with this.

I have messed with minimum spark advance in the past on earlier vehicles to reduce the 'feel' of torque management during power downshifts without totally eliminating torque management.

[lt1z350]

set your minimum spark tables mentioned above to 10 degrees everywhere but where it is higher. One thing you will notice is it will shift better wont drop the timing to - values so you still get some torque fall off but not as much. Really woke up my zl1 a10 with out even cracking the tcm yet. Its possible it can help your problem too is why I mention it. If have a log with it doing it post it up so I can see it. Im going to do a fairly larger cam in my 2017 zl1 soon so if its an issue I might see like to help you through it if possible just in case its a problem on a lot of cars and I will have it. I can send you the tuning school walk through the virtual torque too if think it might help. Just explains it all so can understand it a little more. I will say adjusting my e85 tables helped my trans shifting on any e mix where it was mushy compared to 93 only. You can actually make the trans rip hard by adding to the table just too much and will get a dead pedal.
I do have a issue on mine where with all my bolt ons I am getting really low idle timing now but can start a new thread. Just saw this when was going to do mine.

[TriPinTaZ]

set your minimum spark tables mentioned above to 10 degrees everywhere but where it is higher. One thing you will notice is it will shift better wont drop the timing to - values so you still get some torque fall off but not as much. Really woke up my zl1 a10 with out even cracking the tcm yet. Its possible it can help your problem too is why I mention it. If have a log with it doing it post it up so I can see it. Im going to do a fairly larger cam in my 2017 zl1 soon so if its an issue I might see like to help you through it if possible just in case its a problem on a lot of cars and I will have it. I can send you the tuning school walk through the virtual torque too if think it might help. Just explains it all so can understand it a little more. I will say adjusting my e85 tables helped my trans shifting on any e mix where it was mushy compared to 93 only. You can actually make the trans rip hard by adding to the table just too much and will get a dead pedal.
I do have a issue on mine where with all my bolt ons I am getting really low idle timing now but can start a new thread. Just saw this when was going to do mine.

I have an M7 so I don't have the timing issue on shifts but I still think there may be some help in the minimum spark tables as mentioned. I haven't had a chance to do any testing on this as I have been traveling for work.

[TriPinTaZ]

Its possible it can help your problem too is why I mention it. If have a log with it doing it post it up so I can see it.

Here is a log and a screenshot showing where the TMA drops off right around 2800 while accelerating. It's so odd how it just literally drops to zero. I've mitigated some of it with cam spark, but I've seen where torque management advance even pulls some of that timing out.

taz013.hpl

taz013b.PNG

[Tapout Tuning]

Someone here knows, but they aren't telling.

Has anyone had any luck resolving this issue with timing being pulled in first gear after launch?

[TriPinTaZ]

I've been able to mitigate a majority of the issue I had by increasing the Driver Demand, reducing the Cam Retard under the High Baro table, and increasing VCP spark in the area. I also added a couple of degrees of timing in the base spark table in the offending area. I also revised my Virtual Torque by increasing the values different amounts for both Airmass and MAP at different percentages based on load. Example, at a low airmass/map I increased VT through all RPMs by a small amount and gradually increased the percentage multiplied as the load goes higher.

I think that the Torque Management Advance just normally behaves this way as I see the same thing happening on my datalogs when the car was stock, but it was far less intrusive.

[Higgs Boson]

This issue is directly related to improperly adjusted Virtual Torque table (torque coefficients).

Think about how a big cam changes airflow (and therefore torque) in an engine.

Think about how the torque based controller will react when actual torque is either higher or lower than what it expects.

Make adjustments accordingly.

[TriPinTaZ]

This issue is directly related to improperly adjusted Virtual Torque table (torque coefficients).

Think about how a big cam changes airflow (and therefore torque) in an engine.

Think about how the torque based controller will react when actual torque is either higher or lower than what it expects.

Make adjustments accordingly.

Agreed, Virtual Torque made the biggest improvement in my issue. But then I also needed to change the Driver Demand table to increase the torque requested.

[Ghostnotes]

set your minimum spark tables mentioned above to 10 degrees everywhere but where it is higher. One thing you will notice is it will shift better wont drop the timing to - values so you still get some torque fall off but not as much. Really woke up my zl1 a10 with out even cracking the tcm yet. Its possible it can help your problem too is why I mention it. If have a log with it doing it post it up so I can see it. Im going to do a fairly larger cam in my 2017 zl1 soon so if its an issue I might see like to help you through it if possible just in case its a problem on a lot of cars and I will have it. I can send you the tuning school walk through the virtual torque too if think it might help. Just explains it all so can understand it a little more. I will say adjusting my e85 tables helped my trans shifting on any e mix where it was mushy compared to 93 only. You can actually make the trans rip hard by adding to the table just too much and will get a dead pedal.
I do have a issue on mine where with all my bolt ons I am getting really low idle timing now but can start a new thread. Just saw this when was going to do mine.

This worked for me, setting the spark minimum, torque reserve etc. I'll have to go back and check my notes, but by the time I was done I was idling a pretty darn big cam at 750 and would start right up, hot or cold with no hunting. That was on the MAF side with no wideband. I just watched my timing, trims and O2.Thats about as far as I got then my YSi came in and it's been up on racks for 2 months waiting on headers.

[Higgs Boson]

one other thing I had to do was add a bunch of fuel to VVE from 400 to 800 RPM and higher load than idle. that quick little dip in RPM when letting out the clutch is enough to screw you up if those cells are too lean. in the latest case of my C7Z with cam and whipple those cells took 30% more fuel.

[Ghostnotes]

Fuel is torque, air is torque, spark is torque....torque is air...

[yellz06]

whoever is willing to pay for the proper fix let me know.

[Haans249]

Looks like the fix is:

ENGINE > FUEL > CUTOFF,DFCO > RPM Limits > Misc > Commanded Torque
RPM Limit Torque vs RPM vs Gear

This table you would need to set Neutral to 6,042 (or another high number) or the car will never rev past about 5000 RPM in neutral. I believe that neutral counts for any gear if the clutch is depressed. But if it doesn't in your particular car you can set the whole table to max value and see if it gives you the desired result. If you're just trying to launch the car in 1st, try just 1st and neutral.

My client wasn't able to throw "mean revs" at the competition during roll races and parking lots in Mexico. Something I've never thought of lol. But I found this table fixed the "issue".

This was posted by TriPinTaz on another thread and I tested this on a buddy's car. No longer bogs on launch with a manual. I upped the 1st gear and Neutral to a torque value above the max torque for the motor (anything above 500). No more bogging on launch.