1000ft/lb with 6hp28 on N54? (maxed out 1060HP/920ft/lb with 6HP21)

Brule

Sergeant
Feb 20, 2017
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335i 2007 6spd manual
How much timing advance are you using to get that power?
 

Scorpstan

Corporal
Feb 27, 2017
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335i
its interesting because Diesel cars have max rpm 5.5k. over this rpm my car wont shift from 4th to 5th. think its an adaptation prob or maybe a Kind of Software and communication prob.

So did an adaptation reset and switch to old valve body. xhp told me it is not allowed to Mix other valvebodys with tcu (my 21 valvebody what have the same Part number). now will test shifts around 650lb.
 

Scorpstan

Corporal
Feb 27, 2017
111
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335i
so, i did some runs on street with 950hp 790lbs.
same problem here. i shift at 7k....but trans wont shift. it shift if i left of pedal.
any ideas?

i am close to say that this swap doesnt work how it should be.
 

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MR-KRAKA

Specialist
May 23, 2020
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I’m not sure what all you have for a custom file with xhp but you may need to flash the tcu with a oem gas version for that trans first. Then load xhp. I believe the diesels have a 5500rpm limit odd that it’s only bothering you from 4-5 though. Finding the right file may be tough.

Are you manually shifting? Maybe try letting it shift itself in D or S and see if it’s tied to a certain mode.
 

zomski101

Private
Dec 28, 2019
39
8
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335i
so, i did some runs on street with 950hp 790lbs.
same problem here. i shift at 7k....but trans wont shift. it shift if i left of pedal.
any ideas?

i am close to say that this swap doesnt work how it should be.
I had/have a similar issue but it started on just a regular OTS stage 2+ and xhp stage 3 tune and effected my 2 to 3 shift. Seemed to happen when I spun up the tires hard in 2nd and the trans refused to shift until a second after I let off the throttle, didn't happen all the time. I'm just regular 6hp21 trans, tried different tuners, had sutphin trans tune and purchased the rebuilt valve body he offers for a different issue. None of which fixed the problem. Ken did recommend I try selecting the shift bog fix in mhd, which reduced the amount of times it happened.
 

Scorpstan

Corporal
Feb 27, 2017
111
126
0
Ride
335i
I’m not sure what all you have for a custom file with xhp but you may need to flash the tcu with a oem gas version for that trans first. Then load xhp. I believe the diesels have a 5500rpm limit odd that it’s only bothering you from 4-5 though. Finding the right file may be tough.

Are you manually shifting? Maybe try letting it shift itself in D or S and see if it’s tied to a certain mode.
i have a special custom file from xhp which is designed for this swap. load it direkt on the trans. nothing with oem gas Version. just Code my VIN on it that xhp App can see it. than flashed the custom file.

yes i shift manually. can try D or S
 
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Scorpstan

Corporal
Feb 27, 2017
111
126
0
Ride
335i
I had/have a similar issue but it started on just a regular OTS stage 2+ and xhp stage 3 tune and effected my 2 to 3 shift. Seemed to happen when I spun up the tires hard in 2nd and the trans refused to shift until a second after I let off the throttle, didn't happen all the time. I'm just regular 6hp21 trans, tried different tuners, had sutphin trans tune and purchased the rebuilt valve body he offers for a different issue. None of which fixed the problem. Ken did recommend I try selecting the shift bog fix in mhd, which reduced the amount of times it Happening

I had/have a similar issue but it started on just a regular OTS stage 2+ and xhp stage 3 tune and effected my 2 to 3 shift. Seemed to happen when I spun up the tires hard in 2nd and the trans refused to shift until a second after I let off the throttle, didn't happen all the time. I'm just regular 6hp21 trans, tried different tuners, had sutphin trans tune and purchased the rebuilt valve body he offers for a different issue. None of which fixed the problem. Ken did recommend I try selecting the shift bog fix in mhd, which reduced the amount of times it happened.
i will try the shift Box fix. thanks
 

Scorpstan

Corporal
Feb 27, 2017
111
126
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335i
flashed with shift bog option didnt help.
D and S shifting didnt help too.
I noticed that as soon as the torque is over 740lbs, it no longer will shift. below 740lbs it shifts. don't know anymore what the problem here is.
i think its maybe a kind of limiter in the tcu software or DME but who knows. this project is died for me....
 

nyt

Sergeant
Sep 15, 2019
328
1
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2010 335xi
flashed with shift bog option didnt help.
D and S shifting didnt help too.
I noticed that as soon as the torque is over 740lbs, it no longer will shift. below 740lbs it shifts. don't know anymore what the problem here is.
i think its maybe a kind of limiter in the tcu software or DME but who knows. this project is died for me....

Why not just adjust your load to torque tables and limit to a bit below there? The TCU should be at full clamping force at those levels, anyway.
 

Scorpstan

Corporal
Feb 27, 2017
111
126
0
Ride
335i
Why not just adjust your load to torque tables and limit to a bit below there? The TCU should be at full clamping force at those levels, anyway.
-we did this now.
-plus got a new file from xhp
-plus support from sutphin....

results are here:
 
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nyt

Sergeant
Sep 15, 2019
328
1
283
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2010 335xi
-we did this now.
-plus got a new file from xhp
-plus support from sutphin....

results are here:

Very nice. What are you trapping in the 1/4?
 
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RTA

Lurker
Jun 17, 2020
21
6
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Nice one!

Maybe you might benefit from a ZF TCU scanner / reader, there is quite a bit of info/data in the TCU not accessible via our regular BMW diag toolsets. These TCU's store a lot of interesting info about temps, events, errors.

See below some vendors pushing ZF diag stuff, no experience but maybe useful to know that there is some good tooling out there like:



I have been working with a ZF factory tech in Germany in the past on my former ZF gearbox, learned that those TCU's are full of interesting diag stuff. He had a specific ODB ZF diag box.