Clemens here from xHP...
As it's next to impossible to transport information through Social Media (it is lost after 2 days...), so we'd like to contribute to the discussion here. A few words as introduction, before we get to the points made here:
TCU-Remaps do not exist on it's own in a sealed environment. They are put onto cars, where owners have flashed the DME, stacked a JB4 on it, coded stuff with Carly and also did some fancy stuff like "flash the DSC from a M-Car onto a Z4, it works awesome". Also some of them are not on matching iStep, but have exchanged units from different MY cars, or maybe only updated their EMF through WinkFP to fix some quirks. All those units communicate with each other. Then someone flashes his TCU and has strange things happen and of course it has to be the last thing changed. Our Job is then to trace that stuff and teach the App how to recognize things and act accordingly. And of course BMW itself also has it's Bugs...it's software and it always has. You can't test that fully. Never. It always surfaces once a few hundred people out there use a product. What we do is develop on proper cars and then release and learn. In case of the DCT development took 15 months, 2 Transmissions and 3 cars. We developed (and are developing) on 335i E92, Z4 35i and M4 F8x.
And once it is out, everyone of course knows within seconds whats wrong.
(it's a non-matching ZB, they use old software, blablabla). All crap. Actually the ZB is just a Number...we could put in someones name their as well, if it makes him happy. A calibration for a Z4 can be turned into one for a 335i in a few minutes. (well we can...) The differences are in mapping and behavior mostly. Only small parts are in fact due to different hardware, which is in case of the Z4 the DEC switch and the EMF parking brake. (and of course all works normal on our own Z4 35i) N54 or N55 is negligible in the TCU mapping. Also EU or US does not play a role, yet there exist different ZBs for them. Some insight: The difference between most EU and US ZBs is different mapping of some gear-hold functions during lateral-G due to US customers seen as the more comfy ones by BMW. Sometimes they change a bit more, sometimes it's only a single bit for a sub-function turned off entirely. Stuff we remap anyway, so no need to care about that. I'm always smiling when comparing "user-experience" in forums between different ZBs and then open those maps and look what is actually changed. Thats why user-feedback is not of value in many cases. Peope just tend to trick themselves. Especially on first impression, when being still excited.
Making a map for single car is "easy". Making it work on thousands of cars with unkown history is the hard part. Everyone contacting us at
[email protected] with issues with his Z4 (btw...to date it's 3 cars/owners) got a custom map and is fine. We are still working on a generic Map-Update, which should be there in a few days.
Now on to the things we read here:
"Launch Control does not work on Track": The "AG" cars use the DSC for Traction Control during LC, which is sub-optimal. The "M" Cars regulate it fully inside the TCU (while DSC is OFF) which is a much faster and precise method. Unfortunately it's not too easy to make the M-LC work on a AG car but with todays update on Android (Apple in a few days) there is a way out, with the "Kickdown Launch" Custom Function. This lets you select 2 type of clutch engagements (Perfomance or Burnout) and set an RPM for it. All you have to do is configure it, set car to DSC OFF, stage it and quickly go full throttle incl. Kickdown. The car will raise the RPM to the set threshold and then drop the clutch (Burnout Mode) or fade it in (Performance-Mode). On "Track" disabling the Creep function will help as well.
Short-Shifting: Thats more an opinion as really an actual error. Can be intended by us and is just not as the user wants it to be or is caused by changed throttle/load mapping in ECU Tune. Shiftpoints in BMW Software are based on raw Pedal-Value. If Tuner applies a more "aggressive" Throttle-Mapping in DME, it inevitably pulls down all Shift-Points. Possible solutions: Ask Tuner to leave that stuff alone, flash Stock DME Map, remove crappy "Throttle-Tuner" (Placebo-Box connected at Pedal), press Sport Button, use Shiftmap-Editor in xHP, check "Use Stock Shiftmaps" in xHP. For instance on our 335i the typical take-off 1-2 shiftpoint is down from 3000 to 2300, with the current FBO DME Map. The shiftmap in the TCU has not changed, but the throttle is adjusted to be more aggressive in the DME Tune, so you are only giving it 20% Throttle, instead of ~ 35% on a normal take-off, which pulls down the shiftpoint. Thats inherent and thats the reason the Shiftmap-Editor is there. There is no "optimal" mapping for all the throttle/load maps all the Tuners out there create. We map for stock Load/Throttle Mapping as that is the only base and consistently tell all Tuners to leave those maps alone. (they often just do not know what they are causing)
"Jerky" Take-Off part-throttle: Purely DME related. Same Topic as above. We did not change anything there. Actually the clutch grabs a bit more aggressive on the Z4 cars, but again...thats just different mapping by BMW, not hardware related. Solution: Similar as above, just be more gentle on throttle or disable creep. This makes take-off in general a bit more smoother as there is no Clutch-Torque added from the Creep-Function itself.
"RPM stays fixed for a short period after shift:" Yes, it does. It always did. You just started to recognize it now. The RPM needle does not show real RPM. (it would wobble all the time) Instead it's a calculated value the DME wants you to see and sometimes very, very alert people acknowledge those small deviations during shifts.
"My Car feels little better": It will feel even more different with the coming updates and will get a lot smarter in terms of driver-recognition in D and S Mode. (change behavior based on braking, cornering, throttle aggression etc.) It will then also blip on itself during braking in Sport Mode.
"Sport+ becomes the same as Sport, only fast in DSC OFF:" Sorry, to disappoint you but Sport and Sport+ is the same shift-speed. It always was. Only D and S mode chose different shift-points, but M mode stays the same. With the stock map you are not even able to access the DSC OFF Shiftmode. (it stays the same as Sport) It's not active in AG cars, only in M3. So the car will shift exactly the same in Sport/Sport+ and DSC OFF with stock map. With Stage 2 and Stage 3 the full potatoe in DSC OFF is unlocked. Try to lower torque reduction to 100 Nm in Custom Settings and see your tyres spin on 1-2 upshift in DSC-OFF.
And just for the record, we are 6 people at xHP.
bmw.spoolstreet.com
