N54 DME torque limits, torque tables and torque reporting discussion

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bradsm87

Corporal
Dec 15, 2016
162
This should keep the XHP threads a little cleaner.

It seems there have been a lot of mixed results with torque limits and torque reporting now that the TCU's torque limit per gear values have been raised.

My understanding of a good place to start is:

- Raise torque monitor ceiling and torque requested torque limit (driver)
- Leave all other tables in the "Torque Limiting Maps" folder stock
- Torque eff divisor (fuel) is a bit of a personal preference thing and either stock or flattened values should be fine

@trebila has no issues with IA80S but has torque limit active issues with IJE0S

@P33P33 has nice high torque actual values as logged by MHD but torque that's being reported to the transmission is hard capped at 536Nm.

@P33P33 MHD log - http://datazap.me/u/pekkapalo/uus-tcu-flash?log=0&data=2-18-23-24-26&zoom=70-148

@P33P33 Testo log - http://datazap.me/u/pekkapalo/4-5th-gear-pull3?log=0&data=1-5-6-9&solo=6


Let's get to the bottom of some of these torque unknowns!
 

P33P33

Private
Apr 3, 2017
41
I actually already tried that.
-torque monitor ceiling and requested torque limit (driver) was maxed out in my tables and others were stock-> resulted the same thing: actual torque in MHD logs over 750nm and with TESTO capped at 536nm.

For everyone else to know my load-to -torque tables are rescaled because of N20 tmap and higher boost. My actual load in the logs is over 175. So even with stock L2T tables that should result over 600nm. My point here is that it doesn't matter whether L2T is stock or rescaled it will still max out 536nm at TCU.

I noticed also one other thing when you are idling your car MHD actual torque is around 45-50nm and with TESTO you are only having like 4 nm. So it's kind of obvious it's not the same logging value we are looking at.
 

doublespaces

Administrator
Oct 18, 2016
7,945
AZ
This should keep the XHP threads a little cleaner.

It seems there have been a lot of mixed results with torque limits and torque reporting now that the TCU's torque limit per gear values have been raised.

My understanding of a good place to start is:

- Raise torque monitor ceiling and torque requested torque limit (driver)
- Leave all other tables in the "Torque Limiting Maps" folder stock
- Torque eff divisor (fuel) is a bit of a personal preference thing and either stock or flattened values should be fine

@trebila has no issues with IA80S but has torque limit active issues with IJE0S

@P33P33 has nice high torque actual values as logged by MHD but torque that's being reported to the transmission is hard capped at 536Nm.

@P33P33 MHD log - http://datazap.me/u/pekkapalo/uus-tcu-flash?log=0&data=2-18-23-24-26&zoom=70-148

@P33P33 Testo log - http://datazap.me/u/pekkapalo/4-5th-gear-pull3?log=0&data=1-5-6-9&solo=6


Let's get to the bottom of some of these torque unknowns!
Have you found the table yet?
 

P33P33

Private
Apr 3, 2017
41
Hi,

Couple of finnish guys did some TESTO logs. One of them was 335i RWD with MHD stage 2 OTS map and XHP stage3. He experienced the same thing than I did. He's maxing out also to 536nm
http://datazap.me/u/p3nari/log-1491329183?log=0&data=0-1-2-3-4&solo=3&zoom=7005-7499

The other guy has 335d and he doesn't have this problem. He is reporting over 700nm which is great. Here is his datalog
http://datazap.me/u/jacques/e90-335d-custom-flash-xhp-stage-3?log=0&data=0-1-2-3-4&solo=1-3&zoom=5850-6210

So if those TCU maps are identical in that way that they have exact same torque limiting maps in gasoline and diesel models then maybe the problem comes from DME. I really doubt that but maybe you @bradsm87 or @jyamona can track it down.

BTW here is log from my stock TCU flash. Pretty much the same "slippage" than with XHP stage3
http://datazap.me/u/pekkapalo/tcu-logia-1?log=0&data=1-2-5-9&solo=2

and here is with XHP stage 3 for comparison
http://datazap.me/u/pekkapalo/4-5th-gear-pull3?log=0&data=1-5-9
 
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bradsm87

Corporal
Dec 15, 2016
162
The very easiest way to get around this 536Nm reported torque limit would be to take a look at somebody's DME map who is not experiencing the 536Nm limit.
 

P33P33

Private
Apr 3, 2017
41
You'll need to work out how to get the reported torque higher first and get rid of whatever you enabled to circumvent Torque Limiter 4.
By reported torque you mean TCU reported or DME? That's already disabled and I'm not getting limiter 4
 

P33P33

Private
Apr 3, 2017
41
The very easiest way to get around this 536Nm reported torque limit would be to take a look at somebody's DME map who is not experiencing the 536Nm limit.
That's aboslutely true. I just haven't seen any TCU logs without that hard limit from n54. But let's wait and see what others report
 

bradsm87

Corporal
Dec 15, 2016
162
By reported torque you mean TCU reported or DME? That's already disabled and I'm not getting limiter 4
I guess getting the torque reported to the TCU higher is not essential but you will need to revert your DME to whatever setup where it DID have torque limit active 4 with the stock TCU flash. After that, I could send you a stock or Alpina flash with a very low torque limit in my suspected torque limit table and you can then check to make sure you DO get Torque limit active 4. If you do, that's the table.

It's a lot of stuffing around though haha.
 

trebila

Specialist
Feb 21, 2017
65
This should keep the XHP threads a little cleaner.

It seems there have been a lot of mixed results with torque limits and torque reporting now that the TCU's torque limit per gear values have been raised.

My understanding of a good place to start is:

- Raise torque monitor ceiling and torque requested torque limit (driver)
- Leave all other tables in the "Torque Limiting Maps" folder stock
- Torque eff divisor (fuel) is a bit of a personal preference thing and either stock or flattened values should be fine

@trebila has no issues with IA80S but has torque limit active issues with IJE0S

@P33P33 has nice high torque actual values as logged by MHD but torque that's being reported to the transmission is hard capped at 536Nm.

@P33P33 MHD log - http://datazap.me/u/pekkapalo/uus-tcu-flash?log=0&data=2-18-23-24-26&zoom=70-148

@P33P33 Testo log - http://datazap.me/u/pekkapalo/4-5th-gear-pull3?log=0&data=1-5-6-9&solo=6


Let's get to the bottom of some of these torque unknowns!
I can see a torque limiter intervention related timing correction (timing is higlhly retarded), in the middle of his run in 3rd, and slightly postshift too, so DME tune is wrong:

 

P33P33

Private
Apr 3, 2017
41
I can see a torque limiter intervention related timing correction (timing is higlhly retarded), in the middle of his run in 3rd, and slightly postshift too, so DME tune is wrong:

You are concentrating wrong issues here! Yes, tune needs tweaking but that issue has absolutely nothing to do with communicating with TCU and it's not affecting to reported torque to TCU either and that reported torque is the issue we should all worry about, otherwise those raised torque limits are no use with stage 3.
And in this log you don't see timing correction because of knock but instead of boost slightly going over target boost which is causing thorttle closures and same time pulling timing. Pretty basic stuff in standalone maps in my experience. Torque limit 4 isn't also active in that log (it's 0 all the time) so no torque limits active in DME!
That postshift torque and timing pull is only because of TCU flash. Didn't happen with stock flash or with alpina and torque and timing would stay up. When I change gears it truly feels like someone jumps on the brake and that you can see in the logs pulling torque and timing. I hope this is adaptation issue.
 

trebila

Specialist
Feb 21, 2017
65
When you hit a torque limiter, it kills timing, not boost targets.

As jb4 doesn't monitor torque limit active parameter, I can't say about this. Only way to know if a torque limiter is hit is monitoring raw timing on all cylinders.

I asked Terry to build a custom firmware to monitor the torque report listenned by TCU, as Testo.

I hope we'll know soon.
 

trebila

Specialist
Feb 21, 2017
65
513nm is really close to 512 nm.
as we apply a 0.5 factor to this PID, If we don't apply the factor, we'd get 1024 nm, which is the maximum torque value in the DME ...
it's maybe not related...
 

bradsm87

Corporal
Dec 15, 2016
162
Any new findings in the reported torque department such as the 536Nm reported torque limit somebody experienced (Despite MHD logged torque being much higher)?
 

P33P33

Private
Apr 3, 2017
41
I still have that limit! I'm on I8A0S. Another finnish dude had this same limit and if I remember correctly he is also on I8A0S. Clemens told me yesterday that he thinks it comes from DME side. This is what he told me:

"That’s coming from DME. I investigated a little more over the weekend and it seems this is the MSD80 hardlimit for sending torque. It’s specific, as all the other BMW Modules can send up to 1024 Nm.
So at the moment it seems this is as good as it gets. Hope to get some help on this from the DME Tuner side."
 

trebila

Specialist
Feb 21, 2017
65
I'd be glad to help, as I don't hit any torque limiter with I8A0S, I can report 1024nm flawlessly.
but I need to log "tcu torque" through the JB4, and currently, Clemens and Terry don't talk the same language about PID ...
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,069
Philly
Interesting discussion here so far! I have been digging into a ton of torque stuff recently on the DME, and will be able to provide some help soon. Also, I'm 95% certain I am able to stop these torque related timing drops, and maybe even all the Tq. Lim Actives as well ;)
 
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