Driver Demand (balance with pedal position)

[WS6FirebirdTA00]

So I have been trying to mainly learn about how the throttle works in these new things, here is where I am at and looking for more info...

It sounds like consensus is leave the negative numbers alone, so I left the top two rows.

I am trying to fix areas where I am at 40% throttle in a given gear and the actual throttle goes up to 70% or more.

From what I gather, PE does not enable unless pedal position is over a limit. The frustrating thing there is I am not entering PE in high loads where actual throttle goes to 100%.

The other thing I did was changed some cells 10% (lower) in attempts to better line up the real torque I am looking to get for that pedal position. I also blended some areas to make it a little smoother transition.

Good, bad, yes, no? I am hesitant to try without some feedback on what you guys do. I was going to leave tow mode alone so worst case I switch to it (assuming that is true).

Thanks.

Stock table.PNGNew table.PNG

[TriPinTaZ]

Don't rape the DD table. Why are you changing the Driver Demand table? If you have increased your peak torque tables then you will need to lower your % torque delta required to enter PE mode. This sounds like your Torque Model is way off. What mods do you have that require changing the Torque Model and Driver Demand tables?

[WS6FirebirdTA00]

What I am trying to do is prevent 100% throttle when I only want/need 50%. That is why I want to fine tune the table to have the demand be what I actually want.

Only mods are catback and airaid intake tube, so essentially nothing. Check out the screen shot. I am over my 40% torque hold for PE (at 95%). The tune has minimal changes at this point, MAF and spark is about it. I am just below my pedal position threshold for PE.

So I am not trying to rape it, trying to dial it in. I am logging pedal position vs. speed and looking at what torque value is ideal for that cell. This way I don't get 100% throttle when I don't need it or want it. I end up seeing the real TPS creep up in areas I am satisfied. If I want WOT, I will give it WOT. I also don't want too low of a TPS threshold to offset the stupidity in the program.

The main concern I have is:

1) Any issues trying 5-10% changes
2) When it downshifts to a higher torque (since I see no table to correct for what gear it is in) do I end up with even less throttle, which is probably a yes - just not sure if it will be an issue

APP vs TPS.PNG

[TriPinTaZ]

Need stock and modified tune to offer advice. With just an intake tube you shouldn't need to change your Torque Model or DD tables at all.

[WS6FirebirdTA00]

All I really want to know is if there are any concerns in the driver demand table. I know the last Gen you could brick the ECM and I have already read on the negative values.

If the main caution is small changes to make sure the throttle won?t hang or won?t open when you need it, I feel comfortable trying in small increments.

I am not touching the torque tables. What I showed in the log happened bone stock too.

[Higgs Boson]

I have a Z06 with a whipple and cam, etc and have a stock driver demand table and stock torque coefficients (VVT table).

See your other thread about the same topic, I replied in it also.

[WS6FirebirdTA00]

Thanks.

Here is my frustration:

- spark is based on the values I put in the spark table
- gear is picked based on the throttle position I have vs. speed
- PE is set based on pedal position I set

The actual TPS is completely unrelated to all of those (spark it is, indirectly).

So I need to lower my TPS threshold and control when it comes on with torque. Not a fan, but I can deal with it.

Then the balance will be downshift timing vs. TPS to avoid this overloaded condition. I don't want 100% throttle, that isn't helping fuel economy.

If we had a driver demand modifier vs. gear, you could map it to give a better PE enable point and avoid 100% throttle when I really only want 50%. I get it is looking for a torque. What I don't like is the torque it is looking for requires 100% throttle or a downshift - when I want neither.

[TriPinTaZ]

Thanks.

Here is my frustration:

- spark is based on the values I put in the spark table
- gear is picked based on the throttle position I have vs. speed
- PE is set based on pedal position I set

The actual TPS is completely unrelated to all of those (spark it is, indirectly).

So I need to lower my TPS threshold and control when it comes on with torque. Not a fan, but I can deal with it.

Then the balance will be downshift timing vs. TPS to avoid this overloaded condition. I don't want 100% throttle, that isn't helping fuel economy.

If we had a driver demand modifier vs. gear, you could map it to give a better PE enable point and avoid 100% throttle when I really only want 50%. I get it is looking for a torque. What I don't like is the torque it is looking for requires 100% throttle or a downshift - when I want neither.

Are you sure you are logging the correct TPS PID? There are two or three of them and one of them has an estimated value rather than true TPS(depending on the vehicle). Also, again torque based logic no longer plays by the rules of Gen 3 and even some gen 4 stuff. Have you licensed your TCM yet? The TCM holds a whole new set of tables to tune. IF it is a 2017+ model year car you would need to have the TCM unlocked by HPTuners.

TPS % is no longer the reference point for the ECU, it now uses Calculated Airmass (MAP/Baro = Airmass) for most things that used to be throttle position or MAP related in the older stuff.

If I am understanding you correctly, you want the transmission to kick down a gear or two with less throttle input than is required by the stock tune? If this is what you want you need to get into the TCM. If you increase the DD tables, all you are doing it telling the ECU you desire more torque at less throttle input. Which directly makes the throttle open more for any given driver pedal input. This will cause the transmission to kick down with less driver pedal input, but the throttle will still open further than you want. And if tuned incorrectly will cause weird throttle surges and high idle among other issues. Again, the TCM is what you need to get into. I'd leave the DD tables stock.

Now for PE mode, DD doesn't directly affect entering PE mode in the sense that you might think. The %Torque Delta in throttle change, and the %Torque value of the Virtual Torque Table is how the car determines to enter PE mode. EXAMPLE: If you have stock Virtual Torque Tables and you increase the DD table, you will enter PE mode with less driver pedal input because you reach the 60-70%(or whatever the value is at the RPM) of the maximum calculated torque(again taken from the VTT). Now on the flip side, if you increase your VTT, and leave your DD tables stock, you will actually risk not entering PE mode because while you told the engine it is making more torque in the VTT, you didn't tell it that the driver wants more of that available torque in the Driver Demand table. Therefore you need more throttle input to reach the % thresholds to enter PE. The threshold %'s can be lowered if necessary. Unless you have a throttle closing issue or a timing retard (Specifically, Torque Management Advance) it is best to leave the VTT and DD as close to stock as possible.

Hope this helps.

[WS6FirebirdTA00]

I *think* I am logging the right PID for real throttle. I logged about all of them. The one I have now 100% lines up with the generic TPS locked in at 84%. When my pedal is 100% this also reads 100%. Attached is the channel list.

I see you saw my TCM post, so yes I have a new one on the way from HPT.

What I really want is to limit the actual throttle closer to what my pedal is doing, to an extent.

I don't want to have the throttle blade open 50-60% when I am just cruising along at 2000 RPM and want to climb a slight grade. You can hear it (with the airaid intake tube now) when the throttle blade opens. I typically need to back off the throttle because it is trying to pull more than I really need. That is why I say the driver demand table is off. It is commanding more torque when I do not need or what it.

I am actually OK with the shift points. I like that it does not kick down on small grades. Since the driver demand table does not appear to have a correction for gear ratio, I was thinking I may need to adjust shift points so it will kick down to avoid going to a high throttle. That being said, I don't like this tweak at the expense of more shifting. The motor creates plenty of low end power to do what I need in he gear it is in cruising at various speeds.

So I feel like I can fix the cruising actual throttle concerns with the driver demand, but I fear that if I get that right the downshift will give even less throttle. I often find myself on a downshift needing to give more throttle to balance it. I wish I had the log noted where the weirdness happens. With what I explained above, the current gear would pull strong, but after the downshift the actual throttle would go from 70% down to 40%.

....now that I think of it, look at the picture I attached of the scanner a few posts above. Actual throttle is 70% where pedal is 30%. It downshifts and the actual throttle is around 45%. This leads to sluggish feeling downshift. It is trying to maintain a certain torque, but when I give it more throttle to trigger a downshift I am trying to tell it I want considerably more.

I just think there is a poor balance of cruising driver demand vs. acceleration driver demand. If we had a table or if it accounted for the gear ratio I think it would be better. If I am in 8th gear at 65 MPH, I never want to see 100% actual throttle. If it needs to go that high, I want a different gear - which I normally get - but I will see 100% throttle briefly before it does. Maybe a few MPH drop in downshift will help that, but I want to change as little as possible. I will play with it when I get the TCM.

All that being said, the issue that started this was the fact that I was not entering PE at 100% actual throttle between 1500 and 3000 RPM. I have now lowered the pedal position and am trying to trigger at a torque over 65% to enable PE. The thing I don't like about that is I don't want to be in PE when I don't need it (I really want it based on load) and I don't want to be going in and out of PE through shifts as torque changes.

I might not be making any sense, if so, I apologize


New Sierra File 7.Channels.xml

[WS6FirebirdTA00]

Just to clarify - the PE concern is the pedal enable threshold. It basically needs to be low enough to not really be a factor since actual throttle can be drastically different. That will force PE more so based on required torque %.

Thanks for all the feedback and advice. I appreciate it and everyone's patience

[TriPinTaZ]

The maximum throttle area % vs RPM table is what keeps the throttle blade from opening up more than 20-30% at low RPMs while in high gear. Since you have an automatic you have to also deal with the torque requested for gear kick down etc. Also, PE delay and PE ramp rate could be why you didn't see the car enter PE at lower RPM's. The factory tune has it running leaner in PE mode between 1500-3000 RPM. So not sure if you were logging PE enabled mode PID or just going off of Lambda.

[WS6FirebirdTA00]

The TPS is what is limiting PE, everything else is satisfied. Not saying I don?t want to get to 100%, I just want to ensure if it does PE enables. I just need to torque to the be final trigger since MAP is no longer an option.

I am loading that tune tonight to see how it does.

[TriPinTaZ]

What I am saying is you can reduce the throttle position (torque request) required to enter PE. You can also change the PE ramp in/out rate and throttle change (torque delta) distance to enter/exit PE. These are defined in HPTuners already.

[WS6FirebirdTA00]

Yes and I have set that up. I only wish the throttle trigger was actual throttle and not pedal. Pedal position is irrelevant for when the motor needs to be in PE with DBW TBs since they are all indirect relationships.

[evolmotorsprt]

Yes and I have set that up. I only wish the throttle trigger was actual throttle and not pedal. Pedal position is irrelevant for when the motor needs to be in PE with DBW TBs since they are all indirect relationships.

I completely understand what you're trying to do and have been interested in this myself. Basically the throttle seems like a logic controller that has no direct relationship with the throttle body and the computer gives you only what it deems appropriate. You want it to feel like a true throttle where the pedal has a direct relationship with the throttle blade position and at a given % it satisfies PE. I'd like this too, so I'm very interested in your results. BTW, if I'm misunderstanding you correct me.

[Higgs Boson]

It's what we all complained about in 2013 also. Nothing has changed in this regard, unfortunately. Change is a part of progress.

[evolmotorsprt]

It's what we all complained about in 2013 also. Nothing has changed in this regard, unfortunately. Change is a part of progress.

Here are a couple DD tables that are very different, for nearly the same configuration of engine and trans. The first one is a 2018 Camaro SS 6MT with a 3.73 rear, and the second is a 2018 Corvette GS 7MT with a 3.42 rear. The Corvette has a much smoother progressive curve to the DD table and the Camaro is all over the place. Is there any reason that the smoother Corvette DD table couldn't or shouldn't be tried in the Camaro?


Camaro:

DD 2018 Camaro SS.PNG

Corvette:

DD 2018 Corvette GS.PNG

[Higgs Boson]

driver demand table is only a demand table. what the ECM does with that demand can be very different in two different cars. don't assume that everything else is the same, especially tables we don't see in the tune.

with that said, don't be afraid to experiment, you won't learn anything if you don't try things.

[TriPinTaZ]

Here are a couple DD tables that are very different, for nearly the same configuration of engine and trans. The first one is a 2018 Camaro SS 6MT with a 3.73 rear, and the second is a 2018 Corvette GS 7MT with a 3.42 rear. The Corvette has a much smoother progressive curve to the DD table and the Camaro is all over the place. Is there any reason that the smoother Corvette DD table couldn't or shouldn't be tried in the Camaro?


Camaro:

DD 2018 Camaro SS.PNG

Corvette:

DD 2018 Corvette GS.PNG

I'm going to assume the Torque Tables and Coefficients are not identical between the cars.

[evolmotorsprt]

driver demand table is only a demand table. what the ECM does with that demand can be very different in two different cars. don't assume that everything else is the same, especially tables we don't see in the tune.

with that said, don't be afraid to experiment, you won't learn anything if you don't try things.

Word. I just wanted to make sure there wasn't an issue messing with the DD tables too much. I know not to touch the negative numbers.

I'm going to assume the Torque Tables and Coefficients are not identical between the cars.

After comparing the two tunes, the torque coeffs are identical for everything except DOD. The Peak Torque is different by a small amount on both cars with the Camaro being 22#ft higher. From what I can see the VT tables are also the same. It's very interesting to see where GM saw it necessary to change the driving characteristics.

Again, thanks guys for your knowledge. It keeps me hungry.