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Author Topic: DSG Fix limiter on med9 Ecu how to ??  (Read 12547 times)
cherry
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« Reply #15 on: October 05, 2019, 05:10:46 AM »

First of all, we're talking about Golf R DSG boxes here, you've thrown in a random Passat file. Secondly, mmr_MMaxGetriebeschutz_ko in that Passat file is 390Nm, and the vehicle output is officially 170PS/350Nm. The temp limiter MmrTemperaMmax_kl is still 350 though.

As for your opinion on how active that map works, that's wrong. See attachment. From 0-138deg, it will allow 350Nm. Between 138 and 145, it will interpolate between 350 and 15Nm, dropping TQ all the way to 145.

Sorry in fact i was talking from wrong car, CFGB is only 350NM. But CFGC is 380NM. I only want to say that there are also cars with more then 350NM limit, and i still doubt the temperature map is limiting to 350NM. I never touched this map and never had any limitation, so i expect this map is active "from" 138° or there is another single temperature value to make this map active first.

I never tried to cheat engine torque output because it simply makes no sense, these DSG are easy to read/write since many many years. I understand you say it´s working, but you can say nothing about clutch wear over lifetime or stress from oil etc. Sure the controller adapts microslip, but then better bend torque output instead of making hard cut at 340NM...

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jochen_145
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« Reply #16 on: October 05, 2019, 05:22:02 AM »

Sure the controller adapts microslip, but then better bend torque output instead of making hard cut at 340NM...

No! Deffendly not.

Alltime, when clutch is controlled, you will have a lot slip, when you bend torque.
So better (most certainly not good) let the DCT run like it is used to and only bend or cut at very high torque, witch are mostly used in status "fahren" und mirco-slip-contoller will do his best to catch the engine speed.
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prj
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« Reply #17 on: October 07, 2019, 02:51:36 AM »

Incorrect is thus subjective. There is no clutch slip in a sensible stage 1 with TQ output called at 340. As for saying it has nothing to do with MDNORM, it absolutely does. The ECU will never report more than what MDNORM is capped to.
There is nothing subjective.
If you reduce MDNORM from 500 to 340 on any DSG box, the feed-forward will be insufficent and the clutches will be CONSTANTLY in the microslip adjustment.
They will be slipping much more than the microslip target non-stop all the time on any increasing torque gradient. Adaptation will also do jack shit, because while on increasing gradient the control will be constantly undershooting, on decreasing gradient it will be as well, as they will be grabbing too hard and the adaptation cancels itself out.
To even suggest such a thing is "okay" means having ZERO knowledge of how the DSG regulates clutch pressure.

If you want to cheat torque a little on the top-end (and you will still have slip issues, but at least not in all daily driving), there are much different methods. You should never ever change mdnorm on any DSG box to underscale reported torque, if you care at all for the longevity of the transmission.

Just because you don't see it slipping 1000 rpm, doesn't mean it's not there.
I really suggest educating yourself a little more on how the microslip controller and the feed-forward works before making stupid statements that someone is going to take for gospel and damage their gearbox.
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msundercober
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« Reply #18 on: October 07, 2019, 03:19:29 AM »

Changing mdnorm was used in the beginning when noone could r/w DSG.

Imho the only right way is to change TQ-limit in DSG-SW.

Regards
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prj
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« Reply #19 on: October 07, 2019, 03:28:02 AM »

It was never neccessary to change MDNORM, even then it was always enough to smoothly underscale the torque at the top end a little.
MDNORM screws everything up, also in normal driving.
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msundercober
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« Reply #20 on: October 07, 2019, 08:23:45 AM »

It was never neccessary to change MDNORM, even then it was always enough to smoothly underscale the torque at the top end a little.
MDNORM screws everything up, also in normal driving.

I agree with you, but this is what many people done in the beginning as a "workaround".
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bamofo
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« Reply #21 on: December 17, 2021, 11:02:51 AM »

There is nothing subjective.
If you reduce MDNORM from 500 to 340 on any DSG box, the feed-forward will be insufficent and the clutches will be CONSTANTLY in the microslip adjustment.
They will be slipping much more than the microslip target non-stop all the time on any increasing torque gradient. Adaptation will also do jack shit, because while on increasing gradient the control will be constantly undershooting, on decreasing gradient it will be as well, as they will be grabbing too hard and the adaptation cancels itself out.
To even suggest such a thing is "okay" means having ZERO knowledge of how the DSG regulates clutch pressure.

If you want to cheat torque a little on the top-end (and you will still have slip issues, but at least not in all daily driving), there are much different methods. You should never ever change mdnorm on any DSG box to underscale reported torque, if you care at all for the longevity of the transmission.

Just because you don't see it slipping 1000 rpm, doesn't mean it's not there.
I really suggest educating yourself a little more on how the microslip controller and the feed-forward works before making stupid statements that someone is going to take for gospel and damage their gearbox.

Bumping this because i stumbled upon it after already going through this issue for a couple months. Eventually i figured it out... But this would have been very helpful as a beginner in DSG tuning.
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KRACER
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« Reply #22 on: December 20, 2021, 05:58:28 PM »

It was never neccessary to change MDNORM, even then it was always enough to smoothly underscale the torque at the top end a little.
MDNORM screws everything up, also in normal driving.
I increased MDNORM to 450, and modified the IOP axis coordinates, and also modified the MAP related to torque loss. Because the original MDNORM is only 400NM, minus the torque loss, the maximum is only 360NM. The actual torque of my car is about 400NM.
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vanrhj
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« Reply #23 on: December 21, 2021, 02:43:57 AM »

Interesting topic and i also could not wrap my mind around this but have much better understanding know.
Increase MDNORM to 450.
« Last Edit: December 21, 2021, 02:54:02 AM by vanrhj » Logged
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