NefMoto

Hi there,
 I am trying to understand how to control my boost with throttle when WGDC is 0%. I have read S4Wiki and probably every post on Nefmoto covering this, but still can't get my car to run as it should.
First of all the car:
Audi TT mk2 2.0 BWA MED9.1 with K03 hybrid turbo, custom intake (MAF housing same dimensions as stock) and 3 inch custom exhaust de-cated.
My current mods:
Audi S3 BHZ KFMIRL and KFMIOP
(https://i.imgur.com/oBhiDFv.png)
(https://i.imgur.com/wOh31L5.png)

Tweaked KFLDRL and KFLDIMX, so I just need to adjust IMX (no seperate linearisation map)- take note it is a very basic map now, it is still under my development.
(https://i.imgur.com/6lgHPPv.png)
(https://i.imgur.com/6DpqO3j.png)

And now to my problem/problems:
I found on S4Wiki section about Base boost and wastegate spring pressure.
I think this is what I am looking for. What I want to do is to use my throttle to lower pressure in the intake manifold when wastegate is 0% and car is still overboosting. In my case this situation happend when cruising around 120kph (2500+ RPM, accelerator pedal 25-30%)
S4Wiki says:

Here comes first problem: In all damoses for MED9.1 there is only KFVPDKSE, no KFVPDKSD. Is it true? There is only this one?
Second problem: KFVPDKSE has different vpssplg_w axis to what I've seen in ME7. Now I should add that in CWPLGU I have "1" value, which means that in my ECU vpssplg_w should be equal to requested boost (absolute pressure)/atmospheric presure.
As you see below values of my KFVPDKSE are <1, which would mean that values of vpssplg_w axis are negative boost ::)
I suspect that in MED9 wpssplg_w axis represent something like (requested boost-atmosperic pressure)/atmospheric pressure
(https://i.imgur.com/eRRjksR.png)

Assuming I am right let's move on.
On S4Wiki I've read that KFVPDKSE values below PSPVDKUG (0,95 in my case) represent areas where requested boost is below spring/cracking pressure which means that even if WGDC=0%, the wastegate reamins closed. So the row in which value exceeds 0,95 should indicate my stock spring/cracking pressure which in my case should be 0,420Bar.
Since I wanted to check if I am right, I've changed all values over 2500RPM of KFVPDKSE to 0,94. This should prevent ECU from going WOT. After that I've changed values over 2500RPM of WDKUGDN to 10%, cause I wanted to see if it will limit throttle angle to 10%. It didn't  :'( What am I doing wrong???? Please help.

You may need to do dissassembly and/or log more of the FEUDK path. In particular, log vpsspls_w to make sure it is doing what you think it is doing.

I'm unfortunately not familiar with MED9 so I'm afraid I can't give you more useful or detailed information. Please keep us updated on your progress.

Hello Nyet. Thank you for your reply. At least you ensured me that, to some degree, my thinking is correct. Also thank you for your translations of FR chapter. I found them really helpful to understand structure of ME7 system! :D
I've found complete translation/english version of ME7.3 FR which can also be helpful. Link below: https://vdocuments.site/fre07e0-rtp.html

Looked through a small handful of MED9 complete a2l's and did not see KFVPDKSD in any.

Thanks a lot vwaudiguy. :)

It’s been I while. I’ve investigated Bosch documentation many many many times and turns out nothing is as simple as I thought. In the and it all comes to basic boost pressure. Properly adjusted basic boost pressure map helps a lot with proper PID boost control and throttle control.
Generally in my case of MED9.1 throttle plate is controlled like this:
Map KFWDKMSNVP gives two variables:
One called wdkobugs which is determined from mnsdkoos and pspvdb_kge. This angle goes through some filters, diagnosis etc to the throttle body. You should not touch this because it is perfectly calculated to the stock throttle body.
Other wdkugd is determined also from KFWDKMSNVP but from different data: msndkoug and PSPVDKUG whis is always 0,95
These two base throttle angles are compered and the lower value is selected. If the wdkobugs is lower, it goes through some filters etc do the throttle body.
If wdkugd is lower then some value is added to it and then it goes through the filters, blah blah and finally to the throttle body.
The mentioned value is calculated like as follows
1-wdkugdn*(vpsspls-0,95)/1-0,95
vpsspls value comes from KFVPDKSE
BUT
If pssol/plgru is lower than VPSPLGUG=0,95, then vpsspls=VPSPLGUG=0,95
When we put it into the equation, it gives us 0.
This is how the MED9.1 controls boost pressure under spring cracking pressure.

It all looks and works beautiful... BUT I STILL HAVE A PROBLEM
When cruising at around 3000RPM at 6th gear with just a little throttle, my actual pressure is around 1400-1500mbar absolute, while requested is around 900mbar.
How do you fix this? I dont want to raise KFMIRL in this area, because it will cause the throttle to open further and thus to accelerate.
Rising base boost here doesnt help.
Should I mess around with KFWDKMSNVP?
As always: please help!


Wysłane z iPhone za pomocą Tapatalk

Below you can find logs and link to them
(https://log.tunezilla.com/assets/log/400608/image/Ky0CElmMf5lT38q0zsuUQmqT)

Link (click on the second tab):
https://log.tunezilla.com/s/nmQKllaQ (https://log.tunezilla.com/s/nmQKllaQ)

Hey Guys!

Im just having same issues like Olobolo. My Problem is, that when i am accelerating at Part throttle near the WG Cracking Pressure the boost surges. In the logs i can see that:

- WGDC is at 0%
- TP-Angle oscillates between 25 and 27 Degree
- Actual Boost is higher than requested boost
BUT: Actual load is almost the same with requested load.

I have read a lot to find a solution, but i cant find a real answer on what to change in my file to get rid of that. In all other situations the car runs great.

The car is a RS4 with upgraded Turbos (550hp) but Wastegates are stock.

I attach the log and my file. Thanks for your help !

Greetings.

http://nefariousmotorsports.com/forum/index.php?topic=9221.0title=

Thanks for your answer!
I've read that thread 2 times before, but i couldnt realy find a answer to my problem. What do i have to change ?
Lower WDKUGDN for that rev range ?

I dont realy know how to handle the KFVPED maps. In the RS4 File the X-Axis is Pressure Ratio ive read. But Pressure ratio for what ?

maybe someone can give me a hint!

Thanks in advance :)

https://s4wiki.com/wiki/Tuning#Base_boost_and_wastegate_spring_pressure

An easy way to make an initial pass is by only modifying the vpssplg_w axis data. Take the ratio of the new pressure to the stock wastegate pressure (e.g. 1.8/1.3 = 1.38), and correct the vpssplg_w axis by multiplying each value by this ratio. This roughly sets base boost for proper throttle control. You can further tune this table by making sure areas below the spring/cracking pressure of the wastegates stays below the value in PSPVDKUG.

RS4 is a little different....

http://nefariousmotorsports.com/forum/index.php?topic=6030.0

This week I tested some Maps by playing with KFVPDKSE/D and WDKUGDN.

I fixed the problem by increasing WDKUGDN in the higher rev ranges and increasing KFVPDKSE/D for PR 1.02 and 1.03.
So if someone is facing the same problem this might be a way to start.

Greetings!

Thank you very much for following up, this sort of information is very valuable.

I have some doubts if software rs4 scheme is in stock form.

Could this be a mechanical thing?
Perhaps your wastegate arm screw is set too tight?