First of all, I don't know if this post belongs in the manual or automatic transmission section.

I did a bad thing today. I was hanging out with my friends at Maximum PSI, a BMW performance shop where it's not uncommon for them to work on 1000HP + BMWs.

They were schooling me on DCTs and showed me a video of an F80 M3 running through the gears of the DCT transmission and I had an epiphany.

I want a DCT in my turbo LS C3 vette!!! Don't get me wrong, I love my 4l80E, but I will try to get the video they showed me and you'll see why. They are 7 speed, electronic, dual wet clutch transmissions with almost instantaneous shifting. Some are set up with a clutch control pedal for aggressive launches while some don't need it. Shifting can be slow and soft for cruising or quick and aggressive for racing.

Gettrag stock clutch DCTs can handle 600 ft/lbs of torque and with upgraded clutches or higher line pressures, way, way over that. Other than clutch wear, they just don't break. The majority of the internals is like two manuals transmissions, each connected to their own multi disk wet clutch and controlled electronically by the internal computer brain.

So the problem is that BMW DCTs have an internal computer that controls the trans. And the protocol to the transmission if highly encrypted and are VIN locked to the engine. When an M3 crashes, the transmission cannot be installed in another car. It's pretty useless and therefore readily available and reasonable . No one has broken the encryption yet to my knowledge.

I understand that there are already some standalone computer brains available to control these and some others in development. These replace the locked internal computers and have to be manually wired in. I'm thinking of either using one of these or designing my own.

The gear ratios:
Gettrag DCT -----------4L80E
1st - 4.806-------------- 2.48
2nd - 2.59 --------------1.48
3rd - 1.701---------------1
4th - 1.277-------------- 0 .75
5th - 1
6th - 0.844
7th - 0.671

So I'm going to try to get my hands on one of these crashed transmissions and research this some more.

At a minimum, here's some stuff that will have to be done.
-An adapter plate to mount the Gettrag to the LS. I've seen an adapter plate to a 2Jz so LS can't be far behind if it's not already out there.
-Some connection between the DCT input shaft and the LS flywheel.
-Fitting the starter.
-Output of the trans goes to a 3 bolt plate connected to a rubber driveshaft isolater (guibo) so going to have to make a adapter from that to 1350 driveshaft.
-Probably have to modify or replace the trans mount, but the one in my Vette bolts in, so maybe not too hard.
-Buy a replacement computer/controller or make my own. Cut the old computer out and wire in the new one.
-Change my DIY 4l80e controller from 4speed w/lockup to 7 speeds and connect to the new computer.
-I already have a parking brake so that's not a problem.
-Adapt the oil cooler lines to the Gettrag.
-Maybe change the rear end rear ratio from 4.10 to 3.70 or 3.50. With the DCT 4.80, stump puller, first gear gear ratio, I probably don't need that much gear in the rear. That means I might cruise at 80 at 1500 RPM? Need to do some math.
-Change the shifter or just delete it.
-Maybe a new length driveshaft.

 

Someone's gotta post the 10 speed shifts faster than the DCT. And since I'm not gonna accomplish what you're about to, it might as well be me.

 

You got my attention. Tell us more about it.

How much is it?
Does it bolt up to an LS?
How do you control it?
How much power?
The more info the better.

 

Plan on doing lots of R&D to make it work with a custom ($$$) fuel management/trans controller setup. Tremec makes the new DCT in the Corvette and GT500... while it will be a few years before they sell them in kit form... I'm sure it is on the horizon.

I looked into making a 2009+ Skyline GTR transaxle work behind an LS motor and aside from the trans cost ($5K+), it needed a SyVecs EFI setup, plus a custom program from some guys in UAE that made it work ($2K), so all in all it was going to be $20K.

There are many sequential transmission options... here is a simpler and lighter Quaife sequential in a road race mustang with turbo V8. This car is nuts with lots of aero! He said the transmission is taking the abuse thus far!

I have a 100% stock T56 Magnum behind my 88mm turbo LS9 powered Mazda RX-7 making around 1200rwhp and it hasn't broken yet in YEARS of abuse.

 

Sounds super interesting! Keep us updated. And BMW, those jerks, encrypting the vin and computer to the transmission; so worthless and makes for a lot of car landfill if you can't reuse a part like that.

 

Yes, it won't be done by tomorrow. I'm not sure about the custom fuel management, my DIY transmission controller already ties into the AEM and can force a throttle plate cut and possibly fuel cut.



Above my budget for sure.

Wow, love that quaife sequential. I want to use it for cruising as well as drag racing, so may not be best solution.

I'll bet the Tremec for the Vette and the Ford will be encrypted. Manufacturers are getting more and more cautious about hacking.

 

https://www.facebook.com/eliseracing/photos/pcb.2537958293155941/2537953086489795/?type=3&theater
The two main companies offering controllers are DKG and GZRacing with their HTG tuning controller.

But as mentioned both do require re-wiring of the mechatronics unit in order to achieve control. I've spoken to a couple of users and whilst yes they do work....they still lack refinement.

MaxxExu from Sweden offer a standalone ecu that will control the earlier DCT boxes ( not F80 yet ? ) natively via CAN, which seems a better solution.

My biggest concern would be...that if you likely need a clutch upgrade that will cost a few thousand dollars....and control over the clutches is critical, and I've seen posts where people have fried clutches even on stock ecu's, that would concern me. Is that a risk of something isnt just right with these aftermarket controllers ?
The gearboxes themselves are cheap though for what they are.

I think there's another company in Poland also making adapters etc for them at the minute.

From the Facebook link at the top of my post, Howell Race Engineering in the UK.

Another company Autobionics offer a load of options using Porsche PDK transmissions too.

 

As for sequentials, I wouldnt be trusting Quaife with anything making power.

I see a US company is now a dealer for Samsonas, they make great stuff and keenly priced compared to some and they've most LS platforms covered. Even the Vette

 

 

The control aspect is easy....IF there is someone to crack it for a viable market.

Which seems unlikely as even the 6L range is poorly supported for aftermarket swaps...and does anyone do the 8 speed ?

The likes of the https://www.dkgecu.com/l/what-is-dkgecu/ and the http://htg-tuning.com/


https://gzracing.se/blog/post/htg-tu...kKdvec6pOuC_wI

can control all manner of transmissions as they remove the OEM/CAN/comms aspect, but will require the user to sort the internal wiring mods and the control strategies, if the suppliers have not already done this.

Viable options...maybe not the easiest options

 

The Samsonas are super high quality; however are rated at 1000 ft/lbs approx... while for most that would suffice... you can buy a $3400 T56 Magnum and it holds 1000rwhp without breaking a sweat.... there is a modified one in full drag Supra running a $$$$ billet 2JZ making 2000rwhp+ and it runs 7.0's@207mph with an H-Pattern box... it has a dog ring conversion on the FACTORY gears, billet shift forks, and some other MINOR tweaks. Factory input and main shaft.... That is impressive!

 

There's no doubt what Grannas has achieved with that box..is beyond impressive !

Samsonas do offer a stronger 5 speed box. That said, they do say nobody has broke one of theirs. But as much as their stuff is good ( I've used a few in Subarus )....I still didnt have the faith to put one behind my engine. But I also didnt want to lose the refinement of a road box hence why I went Magnum.


But the DCT's if they can prove strong....really do open up new avenues. The boxes themselves are cheap. Clutches not so much. But the clutches should tolerate a lot more than a conventional dry clutch, and of course if all the control strategies are correct, should be very refined all round. And 7 gears could be a benefit.
But a lot of the boxes seem to be a 1:1 top gear, which may not suit. I think it's the V8 cars that came with the overdriven 6 and 7 gears which might be easier for most to use.
As to how that affects box or gear strength, I've never found an answer. Clearly a 1:1 top if it's a direct drive would be preferable for high speed use albeit requiring a very tall diff ( or massive rear tyres )

I'm definitely watching the DCT stuff with interest. And the boxes themselves dont even seem overly big. It's just a pity they arent all controlling them with the factory TCM via CAN. Having to break open the box and re-wire it inside...not so nice.

 

MaxxEcu seems to have cracked the code for BMW DCT. They are running one behind a Coyote Mustang. Price seems reasonable compared to t56+clutch kit.

 

Needless to say, I did a quick google search. Looks like they are testing it, but not yet released. Very promising. When there are more control solutions maybe the price of the controls will drop followed by an increase in the transmission price.

 

This is the video that got me interested. First part of the video they have a conventional clutch. Then they swapped in a BMW DCT.

 

The MaxxEcu been released for a while.If I may post a link from another forum ; https://bmw.spoolstreet.com/threads/...trip-car.6142/.
Nisse is the owner of the e30 that you linked and is also possibly the owner/developer of the dkg system that is running the dct in his car. There is an active section on that site dedicated to dct swaps.
Very interesting things posted in it. Just no ls adapter for the dct. With transmissions between 600-2000 dollars an adapter to the ls platform would certainly open some avenues.

 

Nisse is the DKG guy....but I don't think he's related to the MaxxECU stuff ?

The two systems are totally different. MaxxECU are controlling everything via CAN without any modifications to the transmission etc. IMO, a much nicer solution, but does also require the correct shifter and a few other parts. There are good details on their website.

DKG is an Arduino based controller where you need to totally re-wire the mechatronics unit in the box, so all aspects can be controlled independently ( same sort of thing as the HTG )

these can work with any shifter or simple switches, or probably fully automated control if you wanted.

 

Not BMW, but still a relevant and good video

 

I already posted a link with info to an LS adapter. And there are other companies working on them now as well.

 

OK now you've got my attention. I already do arduino based transmission controllers. I have no problem re-wiring.