N54 DME torque limits, torque tables and torque reporting discussion

[dyezak]

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

Hell yea! Here come the broken drivetrain parts hahaha

 

[P33P33]

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

This sounds really promising! Good work!

 

[bradsm87]

The more I look into torque-related stuff, the more confused I get haha. There are so many more tables than what are defined in the XDF and most of the XDF labels and the OLS labels are not self-explanatory.

I'd just love to have a better understanding of all the torque tables and to leave the ones that don't need modifying stock and to use the others as they're supposed to be used.

Has anybody yet been able to provide a Testo log of an N54 reporting higher than 5xx Nm torque to the TCU?

 

[Jeffman]

... 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.

Did you ever figure out whether this was an adaptation issue?

 

[P33P33]

Did you ever figure out whether this was an adaptation issue?

It was an adaptation issue for me. It got better with the last revision of stage 3 so it was definitely flash issue also. It's working really nice at the moment but it took lot more time to adapt than couple hundred miles. It still does the timing pull but I believe that's how it is meant to be.

 

[Jeffman]

Thanks. I'm wondering about DME adaptations as well as TCU adaptations. I'm currently tuning my Load to Torque 1, 2, 3 tables to work better with my scaled tune and current setup (N20 TMAP / 23 psi / 93Oct OEM turbo/exhaust '08 AT 335xi). On another forum, @NYT posted some useful info including the following LTT table for his AWD AT N54, indicating he no longer got any Torque Limit Active = 4 codes:

I just loaded these values and scaled the load axis and I am getting some slight Torque Limit Active = 4 codes under WOT.

So my question is whether it is known whether the ECU and/or the TCU logic will adapt to such slight Torque errors. If so, I'll just drive around some more and give it a few days to adapt. If not, I'll modify the table some more.

 

[doublespaces]

It was an adaptation issue for me. It got better with the last revision of stage 3 so it was definitely flash issue also. It's working really nice at the moment but it took lot more time to adapt than couple hundred miles. It still does the timing pull but I believe that's how it is meant to be.

I had the same problem. Going into 1st gear was the one that took the longest to feel smooth. They say 50 miles I think, but honestly it could take 100+ depending on your driving habbits it seems.

 

[P33P33]

Thanks. I'm wondering about DME adaptations as well as TCU adaptations. I'm currently tuning my Load to Torque 1, 2, 3 tables to work better with my scaled tune and current setup (N20 TMAP / 23 psi / 93Oct OEM turbo/exhaust '08 AT 335xi). On another forum, @NYT posted some useful info including the following LTT table for his AWD AT N54, indicating he no longer got any Torque Limit Active = 4 codes:
View attachment 4649

I just loaded these values and scaled the load axis and I am getting some slight Torque Limit Active = 4 codes under WOT.

So my question is whether it is known whether the ECU and/or the TCU logic will adapt to such slight Torque errors. If so, I'll just drive around some more and give it a few days to adapt. If not, I'll modify the table some more.

I believe that torque limit thing is TCU problem because I had that with 5th gear only and with the tcu flash It's gone. I assume you don't have XHP flash?? I do have an XDF file to bypass torque limits so that dme ignores those torque limits but I'm not sure how healthy it is. I used that well over year without a problem. Then XHP came along with increased limits so I don't have to use that method anymore.
I believe the problem with torque limit 4 is that 5th gear is limited to 460nm or something, don't remember exactly, and rest of the gears are limited to 600nm. So I took TestO logs from TCU and TCU sees maximum torque of 536nm with all the gears. So I bet that if you raise that 5th gear limit to 540nm in TCU bin you will never see torque limit 4 anymore.
To be clear I believe every early models of 335i are limited to see max 536nm from TCU side and that's why Alpina flash helped lots of people having all gears limited to 600nm.
I think changing load to torque tables affect torque values that are told to TCU.
I know AWD has some extra torque limiters but my experience is only from RWD.
I have scaled map too and I raised L2T values from 150 load up to about 50 %. Ihave dynoed the car with scaled map so I can look that 175 load is about 750nm(from the engine) with 23-24 Psi and make calculations for the L2T map to make it as accurate as possible

 

[Jeffman]

Thanks. Very informative. Yes, I have Alpina flash. Will XHD be even better?

 

[P33P33]

Thanks. Very informative. Yes, I have Alpina flash. Will XHD be even better?

It's definitely better.

 

[Jeffman]

Okay. I'm sold. XHP will be my next mod.

 

[P33P33]

Okay. I'm sold. XHP will be my next mod.

If or when you do that update I recommend to drive several miles. I'm quite sure you will feel that it's not working like promised at first but be patient and drive several hundred miles!! In my case the adaptation took lot more than 50-100 miles!!

 

[Jeffman]

Thank you. I heard that, too. I also heard that TCU adaptation doesn't start until the transmission fluid temperature is above about 170F. Do you know whether or not that's true? If so, that alone takes ~20 minutes driving to get up to temp.

 

[P33P33]

Thank you. I heard that, too. I also heard that TCU adaptation doesn't start until the transmission fluid temperature is above about 170F. Do you know whether or not that's true? If so, that alone takes ~20 minutes driving to get up to temp.

I haven't heard that before so I have no idea.

 

[doublespaces]

To be honest...it seemed like getting everything to REALLY feel good, it took probably 100-200 miles. That may have been due to my driving habits, but it really does need time to learn, but once it does, the new shifting behavior is there.

 

[Jeffman]

Are the Torque limits in the XHP Stage 3 flash higher than the Torque limits in the Alpina flash? If so, can we now use higher Load-to-Torque values in the ECU flashes?

 

[doublespaces]

Are the Torque limits in the XHP Stage 3 flash higher than the Torque limits in the Alpina flash? If so, can we now use higher Load-to-Torque values in the ECU flashes?

The stage 3 has no limits. Its up to the tune to report an accurate torque rating now.

 

[Jeffman]

Interesting. What kind of LTT tables are people using in their ECU tunes with XHP Stage 3?

 

[chrisdfv]

I flashed xhp last night, and I'm still in the process of driving to let the adaptations take place. In the mean time I've been reading up the xhp beat thread to try and figure out what adjustments need to be made on the tune side to take full advantage of this, but all the torque reporting table talk is making my head spin.
Can anyone help shine some more light on this for a newb. I'm jb4 and spxxx tune I adjusted myself. Have been alpina flashed for about 8 months and had no issues with it at all.

 

[JSR1256]

What are you guys using on the L2T axis, stock? Someone mentioned 160/280 would someone show me what that looks like just so I'm 100% clear.