N54 DCT w/M3 Conversion

  • Login or Register, members don't see Ads!
  • Tip: You can toggle the Dark Theme at the bottom of the page

dyezak

Major
May 4, 2017
1,768
Plano TX
::DISCLAIMER::

This conversion requires expert knowledge of module coding and flashing. It will include the requirements to spoof an M3 Vehicle Order inside NCS Expert to allow NCS Expert to code certain modules correctly without modifying the actual Vechicle Order. If you use NCS Expert to code any other module while set up like this you have a high likelihood of bricking those modules. THIS CONVERSION REQUIRES THE USE OF AN M3 3.15 DIFF.

N54 DCT w/M3 conversion

bmw-m3-dct-jpg.jpg


This post is going to be long. REALLY long. I will provide an introduction, and then a table of contents that can guide you to the section you are interested in.

Intro:

A few people have tried to change the rear gear ratio on the DCT enabled cars (N54 or S55) for years with relatively little success. A small group of people have tried changing the N54 DCT launch control behavior. And an even smaller group of people have attempted to figure out the how and why behind the DCT’s behavior patterns.

Our goal with the DCT with this project was to bring adjustable launch control without traction control, shiftlogic, and a stronger M3 rear diff to the N54 DCT community. We treated the DCT as a black box. After 5mo we have not only achieved all our original goals, we have achieved more. We now also understand how to bring MDrive, and MDM to the 335i/335is as well.

Special thanks goes out to the team responsible for this:

@dyezak
@doublespaces
@Bimaxtremeretro
@aus335iguy
@RSL
@Stokes
@LMB335is
@boostE92d
@jyamona
@Hpaula
@NoQuarter
@TireDeathRacing
@BMWJunkie
@derekgates

Table of Contents:

I. Hardware
a. Shiftlogic
b. Adjustable Launch Control
c. MDrive/MDM​
II. Theory
III. How To Guide
IV. Future Development
V. FAQ

Section I – Hardware

So this is probably the first thing you are curious about. What all would you need to buy ($$$$) to enable this functionality. Here goes a nice list and the average used prices on ebay as of this posting.

A. Shiftlogic
a. Electronics
i. M3 GWS - $200
ii. M3 Shift Knob - $100
iii. M3 Center Console Trim - $200
iv. M3 Shiftlogic Button - $25
v. M3 Center Console Switch Cluster (Power, DSC, EDC) - $100
vi. 8pin connector - $10​
b. Hardware (option 1)
i. M3 Diff (3.15) - $500
ii. M3 Axles - $300
iii. M3 Driveshaft - $300​

B. Adjustable Launch Control
a. M3 SZL - $250​

C. MDrive/MDM
a. M3 DSC - $300
b. M3 KOMBI - $300
c. 1M DME Flash – (unkown cost, under development)​

Section II – Theory

So we have been forced to infer functionality in a lot of areas, there is very little that we know for a fact as we haven’t be able to look at a DKG EGS BIN directly at this point. We knew going in that the e9x M3 DCT was exactly the same mechatronic unit, same gearset, same clutches, same functionality as the N54 DCT.

After several months of talking, a small group of us did research on newtis.info looking over wiring diagrams we decided that it should theoretically possible to flash the DCT with the M3 ZB file in WinKFP. We did also predict that would require the use of the M3 GWS (gear shift assembly) and shiftlogic buttons.

The goal was for us to get on the fly adjustable shift firmness (shiftlogic) and adjustable launch control. We fitted the M3 GWS, and the M3 Shiftlogic buttons in a 335is (basic repining of some connectors required) then flashed the M3 GTS ZB file to the 335is DCT using WinKFP.

Initial reaction was that it worked. We had to re-code the KOMBI to allow shiftlogic to be seen, and to get the tachometer to work which wasn’t predicted but it was pretty easy. But while we did have shiftlogic, we didn’t get adjustable launch control. We also had an unexpected sideffect of “soft” or “mushy” shifts. We did however get full traction control disabled during Launch Control!

There was a theory floated that the M3 KOMBI (being a gateway module) could be having some impact on speed/rpm values. So we fitted an M3 KOMBI. It was an easy, well documented procedure so no problems there. The end result however was that the KOMBI did nothing for us. BUT the KOMBI would prove valuable much later down the road.
Next theory was the 335i DSC was causing some issues…we needed to swap over the M3 DSC. So we fitted the M3 DSC and had loads of issues. Long story short we found @Bimaxtremeretro who explained how to fool NCS Expert into believing the car was an M3 without updating the VO, we could then default code the DSC and perform all adaptation procedures.

Now we had an M3 DSC installed but it did nothing to fix our issues. But because the SZL and DSC units are paired we thought that the M3 MDrive SZL unit would be required…and upon fitting this we found that we got adjustable launch control!! Some newer cars may already have the correct SZL that outputs the correct signals for adjustable LC (mostly post N54 cars...).

We were left with a fully functional M3 conversion but with “soft” “mushy” shifts. It was around this time that @jyamona found the DME subroutine for launch control where the DCT would send a request to the DME to hold a particular RPM via a PT-CAN message. @jyamona proved that he could hijack that routine and input whatever value he wanted in there instead of relying on the PT-CAN requested RPM value.

Doing some logging we then observed that on a shift the RPM was not dropping as much as it should for the next gear. It was being held artificially high. We took this revelation and applied the BMW marketing material which touted the DCT as providing smoother downshifts because it rev-matched (blipped) the throttle on a downshift. Effectively the transmission was using the exact same DME subroutine during launch control as a downshift…it was simply sending a PT-CAN request for the DME to target a specific RPM for the shift to occur. So then we inferred that the DCT could be doing this on regular upshifts as well.

Taking that knowledge back to our clean logs we did some math and found that we were right on the money. The shift was always targeting an RPM that lined up with the final gear ratio being 3.15….but our test car (335is) had a 2.56 rear gears. So the clutches were slipping excessively due to the RPM being WAY higher than it expected. This was our soft/mushy shifts.

We fitted our car with a M3 3.15 LSD and instantly had flawless shifts! All through this process we had people playing with the coding for M Mode in the CIC and we couldn’t get that working. Pressing the M button on the steering wheel and having all your preferences loaded would be nice.

@bimaxtremeturbo came back to the rescue here. He got M Mode and MDM mode to work on a car down in Australia only after swapping over to the 1M DME flash. Turns out this is the last piece of the puzzle, the DME actually interacts with all the other powertrain modules when calling up M Mode or MDM and instructs them to call up the selected pre-sets.

As it sits I (@dyezak) have applied all this theory to my car except the 1M DME flash. Everything except the M button on the steering wheel functions flawlessly. We will be making this change in the near future just to prove out the theory and eliminate any/all variables. But I am now driving a true BMW mutt, half 335 and half M3. It has an M3 KOMBI, M3 SZL, M3 DSC, M3 GWS, M3 Center Console, M3 Switch Cluster, M3 Shiftlogic Buttons, M3 Rear Diff, M3 Axles, Custom Driveshaft, M3 DCT Flash.

As you can imagine this was a long, expensive process. It was a valuable learning experience however. And we want the community to have this knowledge.

Section III – How to Guide

This is so large of an endeavor it is an external PDF found here:
https://bmw.spoolstreet.com/attachments/m3-drivelogic-and-m-drive-on-a-non-mver2-pdf.9691/

Section IV – Future Development

We are looking to bring MDM mode to my car to test it out. The M3 DSC only has on/off…there isn’t a “half on” setting like the 335i has. As such you can get in a lot of trouble fast with DSC full off. MDM mode would be much welcomed. So we will be applying a 1M DME flash soon to prove the last piece out.

Section V – FAQ

TO BE DEVELOPED AS QUESTIONS ARE ASKED

Section VI – Glossary

VO – Vehicle Order
SZL – Steering wheel clock spring
DSC – Dynamic Stability Control (ABS Unit)
KOMBI – Gauge Cluster
DCT – Dual Clutch Transmission
DKG – German Acronym for Dual Clutch Transmission
TCU – Transmission Control Unit (for the purposes of this article, this is an American term and is used for ease of conversation)
EGS – This is the real name of the transmission control unit
GWS – DCT Shifter Mechanisim
DME – Digital Motor Electronics or the computer that runs your engine
MDM – M Dynamic Mode
Shiftlogic – The on the fly adjustability of shifts

 
Last edited:

blisstik

Corporal
Mar 27, 2018
151
I still can't believe this. Is the M3 center console mandatory? I purposely bought a 6MT w/o the NAV for the cleaner interior look.

Also, how much is the actual DCT? And is there a reason for getting a custom length (assumption) driveshaft?
 

derekgates

Corporal
Feb 23, 2018
134
NW FL
I still can't believe this. Is the M3 center console mandatory? I purposely bought a 6MT w/o the NAV for the cleaner interior look.

Also, how much is the actual DCT? And is there a reason for getting a custom length (assumption) driveshaft?
Yes, you need the center console for the "GWS" which is the shifter unit; it houses hall sensors and circuitry that the DCT and DME use to change modes/gear/etc.

The DCT comes with 335is cars (mine included). It happens to be the same hardware as the M3 DCT cars.

The drive shaft is needed because of the M3 rear end required for this retrofit (for now). The M3 diff and half-shafts bolt up to the 335i* rear subframe but the drive shaft differs; the splines differ from the 335i and the length is different on M3 vs 335i.
 
  • 2Like
Reactions: Jeffman and blisstik

blisstik

Corporal
Mar 27, 2018
151
Ahh this is for 335iS cars with DCT already. Hoping the guys with 6MT or AUTO can be retrofitted as well.

Yes, you need the center console for the "GWS" which is the shifter unit; it houses hall sensors and circuitry that the DCT and DME use to change modes/gear/etc.

The DCT comes with 335is cars (mine included). It happens to be the same hardware as the M3 DCT cars.

The drive shaft is needed because of the M3 rear end required for this retrofit (for now). The M3 diff and half-shafts bolt up to the 335i* rear subframe but the drive shaft differs; the splines differ from the 335i and the length is different on M3 vs 335i.
 

derekgates

Corporal
Feb 23, 2018
134
NW FL
Ahh this is for 335iS cars with DCT already. Hoping the guys with 6MT or AUTO can be retrofitted as well.
You certainly CAN.... but there is a TON more work and investment involved. Retrofitting DCT is not an easy process in the least. This work is for the shifting behavior of the M3.

What parameters/behavior are you looking for with your 6MT?
 

Christian87n

Lurker
Feb 19, 2018
19
What if you don’t care for launch control? Can you get away with just installing the gws, shifter knob, center console, M3 diff/axles/driveshaft, shiftlogic buttons and the M3 flash?
 

BMSTATION

Lurker
May 9, 2018
16
What if you don’t care for launch control? Can you get away with just installing the gws, shifter knob, center console, M3 diff/axles/driveshaft, shiftlogic buttons and the M3 flash?
If your DSC is 09/2008--> you will have LC, you dont have to change to M3DSC and SZL
 

aus335iguy

Captain
Nov 18, 2017
1,036
If your DSC is 09/2008--> you will have LC, you dont have to change to M3DSC and SZL
Why is that ? The DSC in the test car was a NA ‘IS model and therefore later and adjustable LC didn’t work properly until they were changed....?
 

LMB335is

Sergeant
Apr 12, 2017
262
FOB FL
Why is that ? The DSC in the test car was a NA ‘IS model and therefore later and adjustable LC didn’t work properly until they were changed....?
I think they're confusing standard LC with adjustable LC. Any DCT car can have LC with a few rare EU exceptions that I've read about. Any DCT car's LC can be turned off by disabling the kick down switch. But to have adjustable LC you need the M3 SZL on most cars and I'd do the M3 DSC just to get rid of all the traction nannies and have the availability of MDM and Mdrive in the future.
 
Last edited:
  • 1Like
Reactions: RSL

BMSTATION

Lurker
May 9, 2018
16
Im using M3 GTS GS40 with 09' 335i DSC and SZL and my adjustable LC is functioning no problem and thats with traction completely off,
But i agree to use MDM you need M3DSC
 
  • 1Love
Reactions: BMWJunkie

doublespaces

Administrator
Oct 18, 2016
8,009
AZ
What does MDM actually do?
M Dynamic Mode is just presets for all your M settings if I am remembering that correctly.

Im using M3 GTS GS40 with 09' 335i DSC and SZL and my adjustable LC is functioning no problem and thats with traction completely off,
But i agree to use MDM you need M3DSC
See, I said this might have been a possibility. Do you have a heated steering wheel?
 
Last edited:

Christian87n

Lurker
Feb 19, 2018
19
Why is that ? The DSC in the test car was a NA ‘IS model and therefore later and adjustable LC didn’t work properly until they were changed....?
I guess I should have clarified adjustable LC. I personally don’t have a need for it. I don’t race or track. I just want to be able to adjust how aggressive I want the transmission to shift for those days I’m feeling sporty. My understanding is that I need just the driveogic capability.
 

aus335iguy

Captain
Nov 18, 2017
1,036
Im using M3 GTS GS40 with 09' 335i DSC and SZL and my adjustable LC is functioning no problem and thats with traction completely off,
But i agree to use MDM you need M3DSC
So youve completed the conversion ? What final drive do you have and do you have any issues with shifts beyond third gear being affected ? Ie Does the engine rpm float around and stabilise slowly after shifting 3rd to 4th gear ?
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Top