DIY tuning

[cookiesowns]

The PID WGDC tables aren't as hard to understand some of you make it out to be

Generally you can leave the PID along on stock turbo, and tweak the base WGDC and Feed-Forward tables, along with adder airflow to get what you need. PID only needs to be tweaked if you have different spool characteristics ( high flow, or catless ) along with a way more aggressive WGDC base/feed-forward tables.

 

[bradsm87]

The PID WGDC tables aren't as hard to understand some of you make it out to be

Generally you can leave the PID along on stock turbo, and tweak the base WGDC and Feed-Forward tables, along with adder airflow to get what you need. PID only needs to be tweaked if you have different spool characteristics ( high flow, or catless ) along with a way more aggressive WGDC base/feed-forward tables.

You're thinking either N54 or Cobb's incorrectly labelled N55 tables.

N55 does not have WGDC Base. The WGDC starting point is a calculation based on many tables.

 

[Sbrach]

Right. “WGDC base” is replaced by a compressor characteristic map that calculates the turbine power required to turn the compressor and a model of the exhaust gas flow characteristics that requires a neural network to calculate. It is incredibly complex.

That said most of the complexity is likely irrelevant with regards to tuning because the PID “takes up the slack” and I will be transitioning to PID control for my PS2 tune due to numerous factors. But just because you can make PID work in no way means that the model is easily understood or in reality understood well by anyone other than the engineers who implemented it. Perhaps with better documentation it would be better understood but I think any more documentation surfacing that we don’t already have is unlikely.

 

[Jeffman]

The PID WGDC tables aren't as hard to understand some of you make it out to be

Generally you can leave the PID along on stock turbo, and tweak the base WGDC and Feed-Forward tables, along with adder airflow to get what you need. PID only needs to be tweaked if you have different spool characteristics ( high flow, or catless ) along with a way more aggressive WGDC base/feed-forward tables.

Interesting. Which table in TunerPro is the Feed-Forward table?

 

[cookiesowns]

You're thinking either N54 or Cobb's incorrectly labelled N55 tables.

N55 does not have WGDC Base. The WGDC starting point is a calculation based on many tables.

No. I'm referring to BM3's table.

Take a look at KF_WGPOS_VST (Wastegate Position - für Vorsteuerung) & Wastegate Position - Modell

I refer to WG position Modell as base. as that's the base derivative.

Interesting. Which table in TunerPro is the Feed-Forward table?

KF_WGPOS_VST (Wastegate Position - für Vorsteuerung)

 

[all4bspinnin]

KF_AUSY_TURB - Turbine flow characteristic
KF_ATM_ATLETA - ATL efficiency
KL_ETA_TURB - Turbine efficiency
KF_FGAS_WG - Gas force on the wastegate
KLEWGFGAS - Characteristic: wastegate force vs duty cycle

I've been doing research comparing the cobb ATR guide on Ecoboost boost control. I've been reading to see if there are any similarities between the feed forward tables (Wastegate Position - für Vorsteuerung 1/2).

 

[houtan]

Right. “WGDC base” is replaced by a compressor characteristic map that calculates the turbine power required to turn the compressor and a model of the exhaust gas flow characteristics that requires a neural network to calculate. It is incredibly complex.

That said most of the complexity is likely irrelevant with regards to tuning because the PID “takes up the slack” and I will be transitioning to PID control for my PS2 tune due to numerous factors. But just because you can make PID work in no way means that the model is easily understood or in reality understood well by anyone other than the engineers who implemented it. Perhaps with better documentation it would be better understood but I think any more documentation surfacing that we don’t already have is unlikely.

Would love to know the reasons why the switch to PID control. I am guessing I should be switching for the same reasons.

 

[all4bspinnin]

Would love to know the reasons why the switch to PID control. I am guessing I should be switching for the same reasons.

PID control allows boost to adjust for all conditions: temp, altitude, ect, etc. PID is also very helpful as the wastegate ages. It can adjust to add more dc as things get lose.

 

[Jeffman]

One of the issues I had with the Non-PID logic (N20 TMap Scaled with MBoost Option for 22-23psi stockers) was an overboost error when accelerating on the highway from like 50 mph to 75 mph in 6th gear (AT AWD), which would throw me into limp mode. Needed to clear errors twice in MHD to clear limp mode. As soon as I went back to my PID map, everything else being the same, I’d never go into limp mode. So presumably the PID was doing its thing.

 

[Sbrach]

No. I'm referring to BM3's table.

Take a look at KF_WGPOS_VST (Wastegate Position - für Vorsteuerung) & Wastegate Position - Modell

I refer to WG position Modell as base. as that's the base derivative.




KF_WGPOS_VST (Wastegate Position - für Vorsteuerung)

Those tables still require the model of the exhaust gas flow over the turbine is accurate and with catless downpipes, exhaust changes, aftermarket turbos, etc this is not the case.

Would love to know the reasons why the switch to PID control. I am guessing I should be switching for the same reasons.

With PID control we should be able to reduce the boost spikes we see post shift, going WOT and downshifting, high gear low rpm WOT, etc. These scenarios are hard to tune around when just using commanded WG.

 

[houtan]

With PID control we should be able to reduce the boost spikes we see post shift, going WOT and downshifting, high gear low rpm WOT, etc. These scenarios are hard to tune around when just using commanded WG.

Looking forward to hearing how it goes. My current commanded wgdc tune is really good in terms of boost control. But I will still switch if there are advantages.

Any progress on understanding misfires because of the stock dct flywheel?

 

[Jake@MHD]

With PID control we should be able to reduce the boost spikes we see post shift, going WOT and downshifting, high gear low rpm WOT, etc. These scenarios are hard to tune around when just using commanded WG.

PID isn't active with commanded WGDC on N55 / F-series? Yikes. I might need to change that logic a bit for you guys.

 

[LamboLover]

If I recall, PD is in the compressor power block that is bypassed by commanded wastegate. I is still used. Alterations could be good and I would like a simpler to tune method that automatically learns the wastegate.

 

[Sbrach]

If I recall, PD is in the compressor power block that is bypassed by commanded wastegate. I is still used. Alterations could be good and I would like a simpler to tune method that automatically learns the wastegate.

Yeah from what I can tell this is correct. Replacing the compressor power / turbine exhaust mass flow model with a WG base table that doesn't get rid of the P and D terms after would be pretty nice.

Looking forward to hearing how it goes. My current commanded wgdc tune is really good in terms of boost control. But I will still switch if there are advantages.

Any progress on understanding misfires because of the stock dct flywheel?

Desensitizing knock in the narrow rev range we see the harmonic and only for cyl 5 and 6 seems to have helped. There are more knock tables I can likely define but I don't really think this is the path anyone should take since M-Fsctory is going to be producing a single mass replacement flywheel for a reasonable price.

 

[all4bspinnin]

PID isn't active with commanded WGDC on N55 / F-series? Yikes. I might need to change that logic a bit for you guys.

Would it be possible to create RPM x Setpoint for us?

 

[LamboLover]

How would you want it to work? Are you trying to separate torque and load from boost and wastegate?

 

[all4bspinnin]

I'd like it to work exactly how it works on the ije0s/i8a0s ecus. The X axis is your boost setpoint, the y axis is rpm. The value in the table is wgdc. In the table a value of 0 would indicate to run spring pressure. Anything above zero means wgdc is applied in order to hit higher boost levels above spring pressure. PID would then be applied.

 

[Sbrach]

That’s how commanded WG works now except the CW to enable that mode also disables much of the PID.

 

[Jake@MHD]

RPM x Setpoint isn't the most ideal in MSD8x either, as it skips over the WGDC spool table and a few others. It also does not exist anymore in IKM0S or INA0S code. For these reasons I started building a more customized approach.

 

[all4bspinnin]

That’s how commanded WG works now except the CW to enable that mode also disables much of the PID.

Correct, the axis are flipped and we'd just need to apply PID afterwards.

Lately I haven't been running spool mode past 3k. I was running spool out to 3500ish on larger turbo cars and blending it in. I've found recently that I can get a more smooth boost curve killing spool mode at 3k. I guess its personal preference really. Spool mode isn't really as much of a concern for me I guess.

My main concern at this point is defining all of the necessary tables in the XDF and making sure we have the correct conversion information. The XDF's I have are filled with a lot of tables still in german with little documented explanation. @Sbrach , id like to get with you about defining a few more things when you have a chance.

@jyamona Mind sharing the details on the customized approach? Or are you using the stock tables with axis edits?