[WedgePerformance]

Hey guys, glad everyone is taking an interest in learning here. Just a heads up, the scaling for the commanded wgdc is wrong. Do not use Boost SetPoint Factor to calculate table position, you must use Boost SetPoint Factor Commanded.

Commanded WGDC (requires switch)

This Table allows a commanded WGDC position to be used much like conventional boost control systems. This table requires the Commanded WGDC Switch value to be set to 1.

Tuning Tips - This table allows a tuner to set a manual wastegate value. The system still maintains some level of compensation (Altitude, temp, P.I.D. Etc.)

The below map is not the IP of WedgePerformance, but a copy of the table from a Stg1 OTS map via ATR. The Boost SetPoint Factor Commanded scaling is a good start. The table values are also a good starting point. What you do with it from here is up to you. Happy Tuning from WedgePerformance....

[bahn]

Originally Posted by WedgePerformance

Hey guys, glad everyone is taking an interest in learning here. Just a heads up, the scaling for the commanded wgdc is wrong. Do not use Boost SetPoint Factor to calculate table position, you must use Boost SetPoint Factor Commanded.

Commanded WGDC (requires switch)

This Table allows a commanded WGDC position to be used much like conventional boost control systems. This table requires the Commanded WGDC Switch value to be set to 1.

Tuning Tips - This table allows a tuner to set a manual wastegate value. The system still maintains some level of compensation (Altitude, temp, P.I.D. Etc.)

The below map is not the IP of WedgePerformance, but a copy of the table from a Stg1 OTS map via ATR. The Boost SetPoint Factor Commanded scaling is a good start. The table values are also a good starting point. What you do with it from here is up to you. Happy Tuning from WedgePerformance....

Thank you for your contribution Ken, we all appreciate it.

Here's my findings so far with commanded WGDC:

* It looks like there's no need to run the commanded boost target switch in conjunction with the commanded wastegate switch
* As Ken said it would appear you need to re-scale the "Commanded WGDC" tables Y axis (boost setpoint commanded) to start around 0.500 or 0.525ish and work its way up from there instead of the stock 1.425 starting set point. At the stock set point you will never get into the meat of the table.

More to come following some additional testing.

[Welcome to NBA Jam]

I've been so interested in ECU tuning as a whole with WinOLS or equivalent. This thread is perfect.

[WedgePerformance]

Originally Posted by bahn

Thank you for your contribution Ken, we all appreciate it.

Here's my findings so far with commanded WGDC:

* It looks like load ceiling is not utilized in this operating mode and that makes some sense.
* It looks like there's no need to run the commanded boost target switch in conjunction with the commanded wastegate switch
* As Ken said it would appear you need to re-scale the "Commanded WGDC" tables Y axis (boost setpoint commanded) to start around 0.500 or 0.525ish and work its way up from there instead of the stock 1.425 starting set point. At the stock set point you will never get into the meat of the table.

More to come following some additional testing.

You still need to set load ceiling as that will define the load and boost ceiling as you still want some safety in place. Alway try to keep load ceiling within 10 of actual.

The Commanded WG Y Axis scaling is correct that I published.

I never did get commanded boost to work and you don't want to use it in conjunction with commanded WG.

[BMWcurious]

PD feedback is disabled when you use commanded wastegate, but I feedback remains. This is because the PD feedback is calculated in the turbine power calculation you are bypassing when you use commanded wastegate.

The second copy of the commanded wastegate is for the 2nd turbo, if present.

[bahn]

Originally Posted by WedgePerformance

You still need to set load ceiling as that will define the load and boost ceiling as you still want some safety in place. Alway try to keep load ceiling within 10 of actual.

The Commanded WG Y Axis scaling is correct that I published.

I never did get commanded boost to work and you don't want to use it in conjunction with commanded WG.

Thank you for clarifying. I made that conclusion because of some oddities I saw when logging my test map. You've obviously tuned a bunch of these cars so we'll go with what you said . The cobb documentation makes it sound like you're supposed to run commanded target with commanded wastegate but that's definitely not true as we both found out.

Originally Posted by BMWcurious

PD feedback is disabled when you use commanded wastegate, but I feedback remains. This is because the PD feedback is calculated in the turbine power calculation you are bypassing when you use commanded wastegate.

The second copy of the commanded wastegate is for the 2nd turbo, if present.

Excellent information, I don't think the MEVD17 was used for any twin turbo cars but it makes sense that the Bosch DME would support it. Thanks for the information!

[BMWcurious]

N63, S63, N74, S55. At least some of those ended up with MEVD17.2.x in production.

[WhatsADSM]

Originally Posted by WedgePerformance

Hey guys, glad everyone is taking an interest in learning here. Just a heads up, the scaling for the commanded wgdc is wrong. Do not use Boost SetPoint Factor to calculate table position, you must use Boost SetPoint Factor Commanded.

Commanded WGDC (requires switch)

This Table allows a commanded WGDC position to be used much like conventional boost control systems. This table requires the Commanded WGDC Switch value to be set to 1.

Tuning Tips - This table allows a tuner to set a manual wastegate value. The system still maintains some level of compensation (Altitude, temp, P.I.D. Etc.)

The below map is not the IP of WedgePerformance, but a copy of the table from a Stg1 OTS map via ATR. The Boost SetPoint Factor Commanded scaling is a good start. The table values are also a good starting point. What you do with it from here is up to you. Happy Tuning from WedgePerformance....

Kudos to you! It can be rare enough to find professional tuners that play nice with each other (I remember this first hand when I used to dabble a bit on the side), let alone one that is willing to share a little research with the DIY community. You have my blessing if anyone ever asks where to get a professional tune

Originally Posted by bahn

Thank you for your contribution Ken, we all appreciate it.

Here's my findings so far with commanded WGDC:

* It looks like there's no need to run the commanded boost target switch in conjunction with the commanded wastegate switch
* As Ken said it would appear you need to re-scale the "Commanded WGDC" tables Y axis (boost setpoint commanded) to start around 0.500 or 0.525ish and work its way up from there instead of the stock 1.425 starting set point. At the stock set point you will never get into the meat of the table.

More to come following some additional testing.

Thanks for the followup. As Ken said it seems to make more sense that we would want just the commanded WGDC on. I can't imagine how both would interact with each other... seems over simplistic if anything (basically always targets a specific row in the commanded WDGC would be my guess).

What units is the "Boost Setpoint Commanded" in? Seems like based on the scaling you and Ken are showing its bar (gauge)?

Originally Posted by BMWcurious

PD feedback is disabled when you use commanded wastegate, but I feedback remains. This is because the PD feedback is calculated in the turbine power calculation you are bypassing when you use commanded wastegate.

The second copy of the commanded wastegate is for the 2nd turbo, if present.

Thanks for the info - this is very interesting information! My reservation about going to a commanded WGDC is the lack of any feedback. I generally like the idea of having some feedback loop in there to fine tune the duty cycle as things do change based a bit based on temps for example. Do you know:

1) If the I-regulator is still in place is there a way to datalog its effect? Also I always wondered how to deal with an I-regulator in a boosted system. Does the integrator hold or clear until it gets passed a "spool" point or something?
2) Are there any other open loop trims that go into the commanded WGDC... like say based on IAT or ambient temp or something. Something that could theoretically help out when using commanded WDGC to get it close to ideal in various environments?

[BMWcurious]

Yes there should be a way to datalog the I effect, but the variable addresses would need to be found and added to the logger you are using. You may be able to imply it with existing logging variables. I am assuming the I effect has the usual anti-windup features, but haven't looked in detail.

The pressure ratio input to the commanded wastegate table is a ratio between the desired inlet manifold pressure and the compressor inlet pressure. It doesn't have (or IMHO require) temperature compensation here.

[bahn]

Originally Posted by WhatsADSM

Kudos to you! It can be rare enough to find professional tuners that play nice with each other (I remember this first hand when I used to dabble a bit on the side), let alone one that is willing to share a little research with the DIY community. You have my blessing if anyone ever asks where to get a professional tune



Thanks for the followup. As Ken said it seems to make more sense that we would want just the commanded WGDC on. I can't imagine how both would interact with each other... seems over simplistic if anything (basically always targets a specific row in the commanded WDGC would be my guess).

What units is the "Boost Setpoint Commanded" in? Seems like based on the scaling you and Ken are showing its bar (gauge)?




Thanks for the info - this is very interesting information! My reservation about going to a commanded WGDC is the lack of any feedback. I generally like the idea of having some feedback loop in there to fine tune the duty cycle as things do change based a bit based on temps for example. Do you know:

1) If the I-regulator is still in place is there a way to datalog its effect? Also I always wondered how to deal with an I-regulator in a boosted system. Does the integrator hold or clear until it gets passed a "spool" point or something?
2) Are there any other open loop trims that go into the commanded WGDC... like say based on IAT or ambient temp or something. Something that could theoretically help out when using commanded WDGC to get it close to ideal in various environments?

Supposedly temp & atmospheric pressure is taken into account but I haven't confirmed that yet. Maybe one of the other guys have and could chime in.

Also note that it would appear the MHD Logging for the parameter "Commanded wastegate base value" appears to be pointing to the wrong memory address as it jumps around constantly up and down. Looks like it might be 1 byte off or not using LSB.

[BMWcurious]

Environmental conditions are taken into account to develop the pressure targets.

[WhatsADSM]

Originally Posted by BMWcurious

Environmental conditions are taken into account to develop the pressure targets.

Okay so all of the trimming takes place in the command? Guess that makes sense it all starts out in torque presumably.

So what is your honest recommendation on boost control? On one hand I can certainly see the allure of going to a straight commanded system. That way you can just have a target load/boost set point that is above the actual load/boost set point. Pretty much guarantees that you won't see any throttle closures unless things get way out of hand. It does seem, from logs I see posted around, that this appears to be a common way to tune.

On the other hand it sort of *feels* wrong to have a load setpoint that can never truly be reached. Kind of throwing away much of the (possibly good) complexity in the modelling. Do you know which tables define the DMEs reaction to an overload/overboost condition? Seems like it might be a little better to open those up a bit but still keep full closed loop control as opposed to straight out switching to an open loop model that always undershoots the target.

[BMWcurious]

Commanded wastegate does not change the load and torque targets, just the calculation of pilot wastegate duty. Throttle closure is thought to be bad at higher boost by some because it can trigger knock. So called commanded boost is nothing of the sort and should be avoided.

The models behind the required turbine power calculations are the way most ECUs are going because they decouple wastegate position control from a specific pneumatic actuator and spring which makes the control modular and it can then be changed to electric wastegate, but can be difficult to understand for aftermarket tuners. Missing PD due to compiler switch removing the code is a small disadvantage, but less than the disadvantage of not understanding what you are tuning.

The pedal to boost target path is long and winding. I have mainly restricted comment away from it to focus on wastegate duty control as getting that right will hopefully help your immediate control needs.

[808AWD325xi]

Perhaps these PIDs will help.

[bahn]

I've got a pretty good E30 map working now using the commanded wastegate strategy. I'm going to make a couple more changes tomorrow and then make a post with a log and some starting tips. Don't expect my entire bin or screenshots of my WG, Fuel and Ignition tables as these took a lot of effort to fine tune. I'll share enough to give people a good jump start though.

[BMWcurious]

bahn, please note that it is the I component that is still operational with commanded wastegate, not D.

[bahn]

Originally Posted by BMWcurious

bahn, please note that it is the I component that is still operational with commanded wastegate, not D.

Yup, was a typo in the main thread. I fixed it Thank you.

[bahn]

Alright, here we go:

This is not to be taken as a guide to tuning the N55. Below are my own anecdotal experiences and not to be interpreted as the only way/perfect way to tune the N55. I don't take responsibility for what you do with this information. My testing was done using the Commanded WGDC Strategy.

Limiters/Initial Setup
* If you're on a 3.5+ bar TMAP and plan on achieving boost levels over ~22 PSI: Increase "Boost ceiling" to 3.5.
* Increase "Boost Limit Multiplier Ceiling" to 3.5, same as above.
* Set the "Boost Limit Multiplier" table to be 4.0 throughout the entire table.
* Increase "WGDC Limit" to 100
* Set the "Torque Eff Divisor" table to be 1.0 for the entire table.
* Set the "Torque Request Ceiling" for your transmission type to be very high. I was using 900 across the entire table.
* Increase "Modeled Torque Limit 1 & 2" tables to be whatever high number you used for "Torque Request Ceiling" for the entire table. (900 in my case).
* To get around auto/dct torque limits you have two options with the "Load to torque limit" tables: 1) Use the stock breakpoints but lower the last two rows cell values until you're no longer hitting the limiter. 2) Use the stock cell values but increase the last two load breakpoints to be very high so the interpolated value is lower.
* Disable the catless CEL code 3106 if you have a catless DP.

Enable Commanded Wastegate
* Set "Commanded Wastegate Switch" to 1 - this enables the commanded wastegate strategy. (Note: Leave "Commanded Boost Switch" off)
* Rescale the "Commanded WGDC" Y axis breakpoints as shown in a previous post by Ken. At higher boost levels you will need to rescale the top end for higher boost setpoints.
* Rescale the "Commanded WGDC" cell values to something like the Cobb table Ken posted above. DO NOT FORGET TO DO THIS, IF YOU DONT YOU WILL BE TARGETING 100% WGDC ALMOST CONSTANTLY.

At this point you can start adjusting your main tables
* Increase "Load Ceiling Main" cell values to your "targeted" load to keep from going over load req.
* Modify your AFR targets (for both banks) and fuel scalar if needed for ethanol.
* Modify your Timing targets by pulling some out to start as you increase boost and rescaling the load axis as needed. Stay very conservative on timing, you'll need a dyno to dial this in safely.
* If your rail pressure starts dropping on higher ethanol mixes you can increase the rail pressure homogen table at the rpm before the crash to buffer it slightly.
* Adjust the "Commanded WGDC" cell values slowly. This will take A LOT of time to get dialed in for drive-ability and boost targets.

Datalog, datalog, datalog. Be very slow and conservative in the changes you make. Take the information above for what it is, my anecdotal experience. Be safe, if you don't know what you're changing STOP and pay for a custom map. The price of a custom map vs a new engine is a no brainer. I personally recommend WedgePerformance

[asrautox]

Great thread!! I'm currently dipping my toes in the water with MHD using TunerPro. I tried the OTS MHD E30 map and was immediately disappointed with the power coming from my self-tuned Cobb E40 map, so I'm back on my Cobb map until I can complete my own MHD tune using the PPK.bin as a starting point.

Regarding commanded WGDC, this is the only way to go if you want to push the turbo to the max. I was able to pick up 1-2 psi on the top end by making the switch. The only thing to be weary of is if you live in Denver like me and drive to lower elevation, you will need to retune your commanded WGDC.

[weehe126]

Bahn, what's your opinion on the BMS BEF load to torque limit values? Only the last row is lower I believe.

[bahn]

Originally Posted by weehe126

Bahn, what's your opinion on the BMS BEF load to torque limit values? Only the last row is lower I believe.

The last two rows are not decreased enough IMO. Auto's will hit the torque limit.

[prima_materia]

I have absolutely nothing to contribute, aside from a giant 'Thank You' to everyone that's put forth their effort and knowledge so that people like me can learn a thing or two.

Really do appreciate it. Been reading the ATR guide for just learning of the various tables - load ceiling, modeled torque limit, torque ceiling, wgdc base, fuel bank 1, fuel bank 2, timing main, etc, etc [I know I'm butchering/probably forgetting tables]. I've probably read the ATR guide several times and this thread numerous times. Slowly clicking bit by bit.

Definitely an empowering feeling to at least have some semblance of what's going on within the inner workings of the DME.