6MT to DCT swap

[Theodore2]

Impressive, I'm interested to see how this turns out and which parts you needed to source in the end.

[amg6975]

Originally Posted by amrazM

if you have the ability purchase a DCT engine harness and replace it, repinning it would be alot of guessing. this will be the only difficult part.

The Engine Harness side isn't even the hard part. It's just a pig-tail that runs from the DME box to the DKG plug. I think maybe the SAP pump wires run in the same bundle?

Inside the car the chassis harness will need to be pulled apart and modified and you can't just swap the chassis harness unless you find the exact same car with a DCT as a donor since in the E9x the harness is made specific for each car.

There are also power and control wires that need to go through the firewall penetrations which will is not nearly as easy as it sounds.

[2226cc]

Originally Posted by amrazM

you need a dct shaft, what are you doing for the wiring? if I could interject here, i did this conversion but the other way around, if you have the ability purchase a DCT engine harness and replace it, repinning it would be alot of guessing. this will be the only difficult part.

Have been looking to the schematics a little just now and for what i can see the MT6 doesn't have a ECU so all the sensors and actuators are controlled by the engine ECU.

Now the DCT has his own ECU. So from what i can see the only thing that connects the engine and gearbox ECU's are two power-train can-bus wires.

I cant really find a reason to repin anything on the engine ecu side

[2226cc]

Originally Posted by amg6975

The Engine Harness side isn't even the hard part. It's just a pig-tail that runs from the DME box to the DKG plug. I think maybe the SAP pump wires run in the same bundle?

Inside the car the chassis harness will need to be pulled apart and modified and you can't just swap the chassis harness unless you find the exact same car with a DCT as a donor since in the E9x the harness is made specific for each car.

There are also power and control wires that need to go through the firewall penetrations which will is not nearly as easy as it sounds.

Also inside the car the shifter is a stand alone module. Also looked it over quickly and it look its just a canbus, power and grounds and like two or 3 wires to some modules noting crazy

[2226cc]

Looked a little closer to the wiring and it looks like the only things I have to connect to the car are:

2 12v power wires from fuse
3 ground wires

2 pt cam-bus wires

2 wires to footwell module right
1 wire to footwell module left
1 wire to car access system

[KhanhyeEast]

excited to see how this turns out, good luck with the project!

[gnx]

Thank you for reporting on your progress. My car is a manual and even though it has the best OEM clutch action of any M car I own, I would seriously consider this swap.

[amrazM]

Originally Posted by amg6975

The Engine Harness side isn't even the hard part. It's just a pig-tail that runs from the DME box to the DKG plug. I think maybe the SAP pump wires run in the same bundle?

Inside the car the chassis harness will need to be pulled apart and modified and you can't just swap the chassis harness unless you find the exact same car with a DCT as a donor since in the E9x the harness is made specific for each car.

There are also power and control wires that need to go through the firewall penetrations which will is not nearly as easy as it sounds.

what are you talking about........ i did this swap

[amg6975]

Originally Posted by amrazM

what are you talking about........ i did this swap

Me too.

I'm not saying you were wrong, I'm just saying the engine side of the electronics box is the easy part compared to doing the chassis side harness.

[2226cc]

So my car is originally a manual and i want to keep it that way so i decided to not make any modifications to the car but instead modify the DTC stuff so i can always swap back to manual and keep it original.

The DCT harness goes up the gearbox into the DME box into the interior. There's noting i need to connect in the DME box i decides its much easier to have the harness enter the car at the gear selector. Also a lot of wires go from the DCT to the gear selector so that would make it nice and clean.

So i modified the orgioal harness and added 2 connectors so i can connect it to the car and take it out whenever i want.

So i now have one 8 pin connector with:
1. Powertrain canbus low
2. Powertrain canbus high
4. 58G illumination signal for shifter and button
5. Park position signal to allow the engine to only start in neutral
6. Wakeup signal for DCT ecu and gear selector ECU
7. Sift-paddle signal ground
8. Shift-paddle signal

And the 4 pins connector:
1. +30G postitive power for DCT
2. +30G Postitive power for gearselector
3. Ground DCT
4. Ground DCT

Power-wires are connected inside the fusebox on the original positions also are the grounds.

From the 8 pin connector 5 wires are connected inside the blue plug under need the glovebox. Park signal is connected on the clutchswitch wire and the illuminatetion control wire i found it was easiest to connect that on the radio wire.

I can now read the DCT and gear selector with my code scanner and everything looks good.

Next step will be to code it all to the car and change the actual hardware it self. Hopefully ill have time in the coming days!

[DrFerry]

Subscribed.

[amg6975]

I don't hate that line of thinking. Definitely easier than going through the firewall and modding the factory harness.

Only thing to pay a lot of attention to is routing of the PT-CAN. There are very specific specs for stub lengths and stuff which is why on the factory DCT harness the PT-CAN goes from the JBBF, through the firewall, down to the gearbox, back up through the firewall again and then to the rest of the car. The GWS is already on a stub of the PT-CAN that I would be very nervous about making longer.

[2226cc]

Originally Posted by amg6975

I don't hate that line of thinking. Definitely easier than going through the firewall and modding the factory harness.

Only thing to pay a lot of attention to is routing of the PT-CAN. There are very specific specs for stub lengths and stuff which is why on the factory DCT harness the PT-CAN goes from the JBBF, through the firewall, down to the gearbox, back up through the firewall again and then to the rest of the car. The GWS is already on a stub of the PT-CAN that I would be very nervous about making longer.

I see! Never knew stub lengths would make a difference tbh, I’ll just see how it goes and other I’ll just wire the canbus differently. I once seen someone connecting a pt can for the gearbox on the fuel pump module behind the back seat and that worked fine so I wasn’t really worried.

[2226cc]

But the last two days I been working on swapping all the hardware, pretty straightforward, taking the manual out was a pain 😆 also got lucky with the clutch. Didn’t noticed anything but it was damaged badly.

[2226cc]

So this is were we are now, got everything coded and my vin programmed into the dct and I was able to drive the car home!

But the only issue now is it’s difficult to find software for the manual 3.85 ratio diff. So now the shifts are harsh and I’m getting codes 5a74 5a75 stored in the DCT.

Now working on getting the 3.85 tune

[M3SQRD]

Originally Posted by 2226cc

So this is were we are now, got everything coded and my vin programmed into the dct and I was able to drive the car home!

But the only issue now is it’s difficult to find software for the manual 3.85 ratio diff. So now the shifts are harsh and I’m getting codes 5a74 5a75 stored in the DCT.

Now working on getting the 3.85 tune

I thought cruising with a DCT w/ 3.62 FD had a high enough rpm for 70 mph. Can’t imagine cruising with a 3.85 FD! Epic is a solid choice for DCT diff FD changes/software but he’s worked with plenty of race builds so perhaps he’s already worked with a 3.85. Software with 3.62 is great.

[DrFerry]

Originally Posted by 2226cc

But the last two days I been working on swapping all the hardware, pretty straightforward, taking the manual out was a pain 😆 also got lucky with the clutch. Didn’t noticed anything but it was damaged badly.

Wow! For a Do-it-Yourself (DIY) project I would say you are mechanically gifted. Well done. Amazing. If you have time to add some more details this thread could become a great resource for people wanting to make the same swap in the future. Great job.

[DrFerry]

Originally Posted by 2226cc

So this is were we are now, got everything coded and my vin programmed into the dct and I was able to drive the car home!

But the only issue now is it’s difficult to find software for the manual 3.85 ratio diff. So now the shifts are harsh and I’m getting codes 5a74 5a75 stored in the DCT.

Now working on getting the 3.85 tune

Go with EPIC Motorsports custom DCT final drive tune.
.
https://epicmotorsports.com/shop/e9xm3
.

[2226cc]

Originally Posted by DrFerry

Wow! For a Do-it-Yourself (DIY) project I would say you are mechanically gifted. Well done. Amazing. If you have time to add some more details this thread could become a great resource for people wanting to make the same swap in the future. Great job.

Thanks! I can do that after it fully working!

[2226cc]

Originally Posted by DrFerry

Go with EPIC Motorsports custom DCT final drive tune.
.
https://epicmotorsports.com/shop/e9xm3
.

Looks good! For now the guy who did the coding for me is looking Into it and if that doesn’t work out I would rather try something more local first. I live a few hours from the nurburgring so I’m sure it will be fine

[gilberjj]

Fun follow, but I’m SHOCKED that you’re converting a 6mt single hump into a DCT car!!!
Cool that you’re figuring it all out, but wouldn’t it have been easier to sell your rare car for any dct car?

[2226cc]

Originally Posted by gilberjj

Fun follow, but I’m SHOCKED that you’re converting a 6mt single hump into a DCT car!!!
Cool that you’re figuring it all out, but wouldn’t it have been easier to sell your rare car for any dct car?

Have done lots of mods to the car already and finding a single hump DCT is really hard.

Also don’t forget I’m from Europe, it’s different, manuals here are normal, 75% of all cars here are manual, every granny is driving one