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Author Topic: KFMIOPS Function MED9.1 / Jerky DSG Issue  (Read 210 times)
armaan
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« on: March 24, 2020, 12:02:38 PM »

Hello everyone.
Hope you all are well.

I want to know what is the function of KFMIOPS in MED9.1. As in how different is its function to KFMIOP.
I have searched before and havent got a definitive answer but from translating the FR:

"Map optimal engine torque for shift operation" ---- "Kennfeld optimales Motormoment für Schichtbetrieb"

Does this mean that this map is only used during a DSG shift? or if the stick is on 'S' or something else entirely?

Backstory:
My cousin has a Audi S3 8P (DSG) Remapped to Stage 2 and its got a power and all but the problem is it jerks at every WOT shift.
Took it back to the tuner and he wanted to charge my cousin $$$ to solve something that is his own tune's problem.
My cousin paid, and the problem still persists, we went back to the tuner and the tuner wants to charge $$$ again.

So I decided to help my cousin out and hoping to solve the issue for him.

What I have done so far:
I have read the file using MPPS and I can see a lot of issues already but not anything particular to the jerky DSG shift issue, which is the main problem here.

I readjusted all LDRXN/ZK such that they request near stock load at 6800rpm, that helped to reduce the jerky shift issue by about half. but the issue still persists. (previously it was requesting 170 load at redline Shocked)

Now my sights are on KFMIOPS, as from translation it seems to have something to do with 'shift operations'.
Would be great if you guys could help me to understand this issue  Smiley
Thanks for reading.

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cherry
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« Reply #1 on: March 24, 2020, 03:08:35 PM »

Your translation is bad, nothing with gear shift, it´s air charge mode. No tfsi is running in "stratified" mode, always homogen mode. So this map isnt used at all.
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Marty
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« Reply #2 on: March 24, 2020, 09:27:30 PM »

Issue is dsg not ecu. Dsg needs to be tuned so not to hit that level of inversion. Btw you sound like you have no clue What You are doing.

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armaan
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« Reply #3 on: March 25, 2020, 05:47:53 AM »

Your translation is bad, nothing with gear shift, it´s air charge mode. No tfsi is running in "stratified" mode, always homogen mode. So this map isnt used at all.

Thanks for your input, and thanks a lot for clearing that out. Now I can hunt other possibilities.

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armaan
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« Reply #4 on: March 25, 2020, 05:58:04 AM »

Issue is dsg not ecu. Dsg needs to be tuned so not to hit that level of inversion. Btw you sound like you have no clue What You are doing.



Thanks for your input.
I understand the DSG TCU limitation is 350nm but I also read that APR tunes initially had this problem but they were able to go past it and thats without tuning the DSG TCU.

I dont know where to read about this in particularly, so I decided to ask you knowledgeable folk.
But from my understanding (could be wrong), at the point of shift the torque must not reach pass 350nm, otherwise this jerky shift issue comes about.
Because once I smoothed out the LDRXN uptop and tapered to stock at 6800rpm, the jerky shift has subsided by almost half.

So I was wondering if there is any other method some of you guys (like APR) have found to get around this issue, without having to tune the DSG TCU. - as there are other threads here that do talk about the same issue but it seems nobody came to a conclusion.

Also wondering if changing KFMIOP values at 6800rpm from 100% down to perhaps 90% might solve the issue further.

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bamofo
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« Reply #5 on: March 25, 2020, 11:39:46 AM »

Thanks for your input.
I understand the DSG TCU limitation is 350nm but I also read that APR tunes initially had this problem but they were able to go past it and thats without tuning the DSG TCU.

I dont know where to read about this in particularly, so I decided to ask you knowledgeable folk.
But from my understanding (could be wrong), at the point of shift the torque must not reach pass 350nm, otherwise this jerky shift issue comes about.
Because once I smoothed out the LDRXN uptop and tapered to stock at 6800rpm, the jerky shift has subsided by almost half.

So I was wondering if there is any other method some of you guys (like APR) have found to get around this issue, without having to tune the DSG TCU. - as there are other threads here that do talk about the same issue but it seems nobody came to a conclusion.

Also wondering if changing KFMIOP values at 6800rpm from 100% down to perhaps 90% might solve the issue further.



Im sure the DSG is different but on the B6/B7 S4 with auto if i max that to 100 it has very ill effects. I max that at 95%
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armaan
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« Reply #6 on: March 25, 2020, 12:11:21 PM »

Im sure the DSG is different but on the B6/B7 S4 with auto if i max that to 100 it has very ill effects. I max that at 95%

Thanks a lot @Bamofo, @Cherry and @Marty will try to understand your suggestions and implement them, and update this as it goes on.

After about a week of playing around with the suggestions above and half a dozen flashes. Lemme just post an update:

First tried adjusting KFDMDAROS, adjusted it all to 50, didnt work, gradually changed it and KFDMDARO maps, didnt work, ended up looking at the wiki again to try and grasp what it really really did and checked FR, realised its probably not what I need.

Then I found MDNORM changed it to 550nm, and adjusted KFMDBGRK (torque limiting for clutch protection).

Had to really play around with KFMDBGRK:
First changed it to 100% through out, with the idea of giving 100% power to the driver. (I know, that was stupid  Roll Eyes) but the DSG jerks did disappear, and I had 'extremely fast shifts', however I knew something was wrong when the DSG farts in 3rd 4th and 5th disappeared and after a while a new sound started from the gearbox, a dull thud between 1st to 2nd, mechanical almost.
Decided lemme not push it, go back to the drawing board and try and properly understand KFMDBGRK and its axis nvquot_w particularly.

Checked in the FR, thought maybe I should change TRBGRK or CWMDBGFZG but then I checked the price of a S3 gearbox that helped me decide against changing those maps. XD
 
So I figured lemme titrate upwards on the torque % for the 6000rpm column, and flash and check. After about 3 different values and 3 flashes I managed to get rid of the jerks. and that thud from the first flash wasnt there either, all the bells and whistles (and farts) came back as usual, been testing it for a while now and its all fine.....so far.

I have very basic understanding of how a DSG gearbox works, and the clutch pressure and all, so maybe if someone with better knowledge can state how this might affect the gearbox in the long run, it would be epic.

Hope this helps someone, Thanks once again.
« Last Edit: April 01, 2020, 08:26:02 AM by armaan » Logged

It is indeed a difference of perception that brings about our and others reality.
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