BMW M5 Forum and M6 Forums banner
Cancel

Let's talk DCT conversion

199026 Views 610 Replies 99 Participants Last post by  gpeterson, 
C
So as many of you know, the DCT conversion has been done, so it IS possible. I've been doing a little bit of research and have put together a very *rough* plan to explore the reality of what would be required to make this work. I wanted to reach out to everyone in hopes that we could accumulate some useful info to help make this happen. So far, I've gathered the following:

1. The bell housing bolt pattern is the same between the SMG & DCT.
2. The shift lever is obviously different; mounting could be different as well as wiring. (will confirm later in ISTA)
3. The DCT transmission appears to have an external fluid reservoir. Lines would need to be run and a reservoir mounted. (Fairly easy)
4. The DCT flywheel has the same mounting bolt pattern as our. It appears that a DCT flywheel will bolt right up to the S85 crankshaft.
5. A vast majority of the wiring for DCT electronics is internal in the valve body. The only electrical connection to the trans is a round 20 pin connector.
6. The crank/trans speed sensors are the exact same PN between SMG3/DCT.
7. Shift paddles are also directly compatible. Electrically, they are the same. (dead short/open circuit triggers when pulled)
8. DCT gearbox suspension/mounting/crossmember appears to be different, but it looks like it could be modified/re-drilled to make the holes line up.
9. M drivelogic button would need to be wired.
10. There may be mechanical differences related to drive shaft length due to possible different length of the DCT trans. (If we're lucky the length difference is so slight it can me taken up in the slip joint allowing us to kep our drive shaft.)
11. Vehicle may need coded to look for DCT. Because DCT was never an option for E60, coding would need to be done with a ghosted VO similar to retrofitting combox. Doesn't the m5 DCT have an e60 M5 kombi in it? If not we may need to use an e90 kombi from a DCT car. (Vin conflicts/mileage issues are easily resolved from the software side.)

Everyone turns a blind eye to this retrofit because they are intimidated by electronics (which happens to be my profession), when actually, this is not very complicated electrically. The DCT connector only has 10 wires....2 are PTCAN, pwr, GND, wakeup, and the rest are from the shifter & M drivelogic button which is a simple bistable momentary ground switch with an integrated LED. It seems like the hardest part of all of this is the software/programming side making everything transmit the right messages and making everything interpret them properly. (Everything PTCAN related) If the DCT shifter transmits its messages on the GWS LIN in the same structure as the SMG shifter, they would essentially be a plug and play swap.

Anyone have anything to contribute?

I have a couple German colleagues who are looking into some additional details too as far as what was required for the M5 CSL project, which would be a huge help. :)
See less See more
Reply
Save
Like
1 - 20 of 611 Posts
3
What about auto-shifting properly when in D mode?

I know changing the rear diff to a different ratio causes issues with that. Are the DCT ratios compatible with our engine rpm?

p.s. It would be really cool if this was a possible substitution if/when the SMG dies although I would be tempted to go 6-speed from the F10 in that case. no need to worry about electronics. Mechanically you'd need more work though.
Reply
Save
Like
C
335xi said:
I know changing the rear diff to a different ratio causes issues with that. Are the DCT ratios compatible with our engine rpm?

p.s. It would be really cool if this was a possible substitution if/when the SMG dies although I would be tempted to go 6-speed from the F10 in that case. no need to worry about electronics. Mechanically you'd need more work though.
Click to expand...
But the car will still run/drive/shift right? Does anyone have the specific fault, which module threw it, etc? If the nuisance of the fault is the only issue, this could also be easily fixed with programming.

Good point, looks like the DCT drives a 3,15 ratio.

DCT Drivelogic

I : 4.780
II : 2.933
III : 2.153
IV : 1.678
V : 1.390
VI : 1.203
VII : 1.000

Gear Ratio SMG3

1st gear 3.985
2nd gear 2.652
3rd gear 1.806
4th gear 1.392
5th gear 1.159
6th gear 1.00
7th gear 0.833


Perhaps DSC coding can be modified to see e9x figures....when I look at my DSC trace, it is a modifiable field.
See less See more
Reply
Save
Like
C
Sub'd, great topic, I'm more than curious myself. There was some Russian board member that supposedly has a DCT retrofit going on by Gintani, but I don't think there has been much updates/progress/info in his thread..
Reply
Save
Like
C
Looks quite an impossible task. Such gearboxes exhange a lot of information with the engine ECU to make the shifts right in every situation.
Must require ability to:
- Completely remap the engine ECU
- Completely remap the DCT ECU
And a few hundred hours testing on a dyno, maybe more...
Reply
Save
Like
C
Cool Cat said:
Looks quite an impossible task. Such gearboxes exhange a lot of information with the engine ECU to make the shifts right in every situation.
Must require ability to:
- Completely remap the engine ECU
- Completely remap the DCT ECU
And a few hundred hours testing on a dyno, maybe more...
Click to expand...
The fundamental operation of the transmission is based on a bunch of exchanged messages on the PTCAN. As long as the messages are still available and valid...operation should still be ok. Calibration to make is shift properly can be accomplished with the many scripts available in ediabas for that specific hardware variant.
Reply
Save
Like
J
Letting the cat out of the bag a bit, the thought may have already crossed my mind to do this. As well as some planning for my E61 build.

- You might be surprised to find that all of the SMG parameters stored inside the mss65 DME are also present in the mss60 DME. The map structure is identical as well as the naming conventions in the development version I looked at one time. Therefore, as long as both DME and DCT module are connected to each other via PT-CAN, we might be surprised and it actually just works. There's a guy in Germany putting a DCT in an E30 with an S85. E30 M3 - supercharged S50B32 [RNGTOY] - PistonHeads

Read the Sep. 21, 2013 entry. He apparently has the software from BMW somehow. I asked to him some time ago if he'd be willing to share it and he implied he might after they get it working.

- Pull all the drive shaft part numbers from ETK and you can deduce that the SMG box is longer than the E60 6MT box, by about 23mm. The E60 and E90 6MT box are identical externally for length. The DCT box is 32mm shorter than the 6MT. Therefore, in order to use a DCT in an E60 or E61, you need a drive shaft 55 longer. Or, have an adapter 55mm machined for the output pinion on the DCT and use longer bolts to engage the Guibo. Problem solved. These numbers may not be exactly correct as they are from memory, I have a spreadsheet at work I calculated it on and will post the actual numbers Monday.

- The transmission rear mount for the E92 6MT is the same part number as the 6MT mount for the E60. This means the mounting holes are spaced identically underneath the car. Therefore, the E92 DCT bracket will fit the E60's mounting holes.

The SMG harness is completely independent from the engine harness, so there shouldn't be much splicing involved. I've been thinking the same thing, but haven't dug into ISTA yet to pull wiring diagrams and pin connections.

- I sourced at DCT box pretty cheap, but haven't pulled the trigger. I've found a few on eBay for around $1500-1800 complete.


Would be nice to have a community effort going on with this. I tend to bite off more than I have time for and that needs to change with the new direction I'm heading in.
See less See more
Reply
Save
Like
C
6
jcolley said:
Letting the cat out of the bag a bit, the thought may have already crossed my mind to do this. As well as some planning for my E61 build.

- You might be surprised to find that all of the SMG parameters stored inside the mss65 DME are also present in the mss60 DME. The map structure is identical as well as the naming conventions in the development version I looked at one time. Therefore, as long as both DME and DCT module are connected to each other via PT-CAN, we might be surprised and it actually just works. There's a guy in Germany putting a DCT in an E30 with an S85. E30 M3 - supercharged S50B32 [RNGTOY] - PistonHeads

Read the Sep. 21, 2013 entry. He apparently has the software from BMW somehow. I asked to him some time ago if he'd be willing to share it and he implied he might after they get it working.

- Pull all the drive shaft part numbers from ETK and you can deduce that the SMG box is longer than the E60 6MT box, by about 23mm. The E60 and E90 6MT box are identical externally for length. The DCT box is 32mm shorter than the 6MT. Therefore, in order to use a DCT in an E60 or E61, you need a drive shaft 55 longer. Or, have an adapter 55mm machined for the output pinion on the DCT and use longer bolts to engage the Guibo. Problem solved. These numbers may not be exactly correct as they are from memory, I have a spreadsheet at work I calculated it on and will post the actual numbers Monday.

- The transmission rear mount for the E92 6MT is the same part number as the 6MT mount for the E60. This means the mounting holes are spaced identically underneath the car. Therefore, the E92 DCT bracket will fit the E60's mounting holes.

The SMG harness is completely independent from the engine harness, so there shouldn't be much splicing involved. I've been thinking the same thing, but haven't dug into ISTA yet to pull wiring diagrams and pin connections.

- I sourced at DCT box pretty cheap, but haven't pulled the trigger. I've found a few on eBay for around $1500-1800 complete.


Would be nice to have a community effort going on with this. I tend to bite off more than I have time for and that needs to change with the new direction I'm heading in.
Click to expand...


This is exciting news....

If we could find someone with a DCT equipped vehicle who would be willing to unplug the trans & cycle the ignition we could see all the messages the PTCAN sends to DME from the DCT. (It will throw a faults for all the missing messages.) The same can be done with DME to see which signals are needed from the DME for the DCT.

We also need someone who has a DCT shifter laying around so we can wire it up to an e60 and see how it behaves. I'm willing to bet it is electrically identical.

I have a lot of stuff out of ISTA i'll post up here in a bit

EDIT:

Here's the DCT flywheel. Notice the pickup tone ring is also the exact same.





DCT electronic requrements:







Paddles:

See less See more
Reply
Save
Like
L
Exciting!
Reply
Save
Like
J
You ready to send me your car yet @ACG?
Reply
Save
Like
  • Like
Reactions: 1
ACG
jcolley said:
You ready to send me your car yet <!-- BEGIN TEMPLATE: dbtech_usertag_mention --> @ACG <!-- END TEMPLATE: dbtech_usertag_mention -->?
Click to expand...
I have been sitting here keeping quiet about this as I know of one shop which has been working on this for almost 2 years + and still do not have a working model to show. If it was as easy as it is listed on here then I would have hoped to see a working model by now, especially after this much time.


Jim if you think you can achieve this then I will happily send you my car :wink
Reply
Save
Like
J
Might lose a little top end...but it will be quick!

All the problems associated with rear end gearing changes on both the SMG and DCT are solved inside the DME. The speed table for the SMG (still labeled SMG even in the mss60) uses just that...wheel speed. But not as read, but calculated by RPM from the selected gear and either CPS or layshaft sensor.

Just going to leave this here...

Text Font Line Number Design


If you want to retain the stock total gear ratio, a shorter final drive gear is an option.
See less See more
Reply
Save
Like
J
While I'm just leaving things here...what's the point of using a stock DCT. Eventually, you're gonna want more power...

BimmerBoost
Reply
Save
Like
ACG
don't mine losing a little top end, I can make up for that in other ways. Just let me know when it's a good time to take a drive down your way :3:, I can always get a flight back via the company :angel
Reply
Save
Like
  • Like
Reactions: 1
J
ACG said:
I have been sitting here keeping quiet about this as I know of one shop which has been working on this for almost 2 years + and still do not have a working model to show. If it was as easy as it is listed on here then I would have hoped to see a working model by now, especially after this much time.


Jim if you think you can achieve this then I will happily send you my car :wink
Click to expand...
The software is the key. Having access to the internal of both the mss65 and mss60 helps. Maybe we can narrow down the differences and create our own.
Reply
Save
Like
ACG
Jim that is a 5 year long thread, I am not going to read the entire thing lol
Reply
Save
Like
J
ACG said:
don't mine losing a little top end, I can make up for that in other ways. Just let me know when it's a good time to take a drive down you way :3:, I can always get a flight back via the company :angel
Click to expand...
You foot the bill for parts and I'll do the labor for free. Not kidding. Can't promise a timeline, but the wiring, mechanicals, installation is all easy for me to conceptualize and lay out. If we get the right people involved in this, the software will be the only challenge. @BrenTuning is a mere 60 miles away and tunes the SMG mapping inside the DME. By default, he would also know how to tune the DCT maps inside the mss60 as well, so could be a very helpful here.

CAN sniffing might come into play. Fortunately, I've done a little of that too.
Reply
Save
Like
ACG
jcolley said:
You foot the bill for parts and I'll do the labor for free. Not kidding. Can't promise a timeline, but the wiring, mechanicals, installation is all easy for me to conceptualize and lay out. If we get the right people involved in this, the software will be the only challenge. <!-- BEGIN TEMPLATE: dbtech_usertag_mention --> @BrenTuning <!-- END TEMPLATE: dbtech_usertag_mention --> is a mere 60 miles away and tunes the SMG mapping inside the DME. By default, he would also know how to tune the DCT maps inside the mss60 as well, so could be a very helpful here.

CAN sniffing might come into play. Fortunately, I've done a little of that too.
Click to expand...
As long as we do not touch the tune for the actual SC then I think I can swing it. I do have a few upgrades going on in the next month with ESS to boost the power level so maybe we should touch bases offline and get down to some figures of actual cost of parts and such. Just need a ball park figure to get a better understanding of this project. Don't worry about the timeline, I will not create a gantt chart to track this one haha!!
Reply
Save
Like
J
ACG said:
...I will not create a gantt chart to track this one...
Click to expand...
Um...I will...:|

It's how my brain works these days.
Reply
Save
Like
  • Like
Reactions: 1
ACG
jcolley said:
Um...I will...:|

It's how my brain works these days.
Click to expand...
Unfortunately mine does also :smile especially now that I am in charge of 3 divisions at my company :crying
Reply
Save
Like
  • Like
Reactions: 1
1 - 20 of 611 Posts
BMW M5 Forum and M6 Forums
M5Board is the best forum community for information on the BMW M5 E60 (V-10), E39 (V-8), E34 (straight 6), E28, F90 and F10. Discuss performance, specs, reviews and more!
Full Forum Listing
Explore Our Forums
E39 M5 and E52 Z8 Discussion E60 M5 and E61 M5 Touring Discussion Parts / Other For Sale or Wanted E63/E64 M6 Discussion E34 M5 Discussion
Top