I'm curious because I've read that the standard 6 speed auto in the earlier F56's can actually hold more power safely than the DCTs. I know that DCTs are fairly expensive to manufacture with higher tolerances. Anyone know anything? I'm more specifically referring to the AISIN 300 from the S/JCW vs the ZF.

 

The DCT in the current F55/56/57 is made by Getrag (7DCT300), not ZF. It’s a transmission that’s actually been around for 11 years now, but only in MINIs and some European FWD BMWs for a handful of years. The “300” in the model number refers to its rated max torque of 300 Nm, which is ~220 lb-ft.

 

I have a '15 F-56S that dynos out at 300flhp & 350 ft./.lbs torque . It's also got a 6sp. auto.-trans. Are you telling me my tranny doesn't have the guts to handle the torque ?

 

Your car has the older Aisin torque converter automatic. Though I don’t know that anyone knows with absolute certainty, there seems to be speculation that the torque converter automatic can handle more power than the DCT. Though, I’ve also seen tuned DCT cars that don’t have any issues. It’s a shame that we don’t have a TCU aftermarket for the DCT (like you find with the VW/Audi DSG gearboxes). Those transmissions can handle a lot of extra power and torque with a rather affordable TCU remap.

 

Sort of. They mostly just remove torque limits which, while allowing for higher levels of power to transmit, isn't really doing anything about wear on clutchpacks and other components.

In general the torque converter autos handle more power better. The JCW still uses one for a reason. The DCT is great for stock power but both that and the manual aren't really built to handle too much more, they're designed to be compact and lightweight and to a degree, cost-efficient

 

You mean 2018+ JCW still use 6 speed auto? Didn't know that.

 

JCWs never got the DCT, went from a 6spd to 8spd Aisin AWF8F35, factory rated for 350lbft.

 

Very interesting. This actually answers my question to some extent.

 

Not really. Having owned several VWs with the DSG, all of which were modified to a decent extent, the DSG gearboxes are quite capable with a TCU tune. Are they bulletproof? Of course not, but with proper maintenance they can last a lifetime even with a tuned engine putting out significantly more power than stock. Even some of the truly nuts aftermarket companies like HPA use DSG transmissions in their vehicles, sometimes with clutch pack upgrades and a TCU remap being the only transmission modifications. However, I have seen DSGs without a TCU tune get finicky after a while when paired with, for example, an ECU tune.

There is no inherent power capacity advantage to a torque converter automatic vs. a DCT. In fact, they basically use the same technology (wet clutches, and brakes in the case of a torque converter automatic, controlling mechanical gears of some sort), most often controlled by hydraulic pressure. It really comes down to what the mechanicals are capable of handling. The case is similar for manual transmissions, where the clutch is often the OE weak point. The MINI/BMW DCT may be at a disadvantage in general compared to other DCTs in that it uses electric-hydraulic actuators to control the clutches, as opposed to hydraulic pressure like is common among DCTs. In that sense, perhaps the MINI/BMW DCT isn’t capable of holding as much power, not sure. But there are quite a few DCT owners in the UK and Europe (where the DCT has been available for longer) who have tuned cars without issue.

And I suspect the actual reason the JCW F56 has the torque converter automatic, and not the DCT, is because MINI doesn’t (well, didn’t) have a DCT that’s rated for the torque the JCW puts out. I believe Getrag makes at least two, the 7DCT400 and 7DCT500 (rated for 400 Nm and 560 Nm, respectively), but BMW and MINI don’t or at least didn’t have them in any of their vehicles. And with an automatic JCW selling in overall low numbers, I’m sure it didn’t make economic sense to homologate yet another powertrain combo into the lineup when they already had the Aisin 6- and 8-speed automatics in numerous models. Which is all a moot point since MINI has moved to an updated DCT for all models, 300+ HP JCW models included, for the F66 generation of vehicles. I acknowledge that with MINI’s move to the DCT in the JCW Countryman, torque is down from 331 lb-ft to 295 lb-ft (which happens to be the 7DCT400’s rated torque capacity), which could be intentionally related or coincidental. Though, BMW/MINI are notorious for underrating their engines so…

 

Oh nice similiar background and I've owned a tuned VAG car with upgraded clutchpacks and TCU tune. What I meant was that yes a TCU tune is a good thing to have, but if you really start pushing a lot of torque a tune alone won't make it magically more durable. Might help a bit (upping clamping force etc) to extend clutchpack life vs not doing it but otherwise... ehh?

As far as auto vs dct, I was speaking to these specific boxes, the Getrag DCTs in the F56 may or may not last long under higher power levels, but I do know that the clutchpacks slip. This was on a completely stock B46 running an E85 tune, really had to play around with torque curves to get it to stop. The manuals also need upgraded parts to take advantage of a good stage 2 setup on E, otherwise you have to walk back the torque as well. JCW Aisin is good to go for all that.

I've been trying to see more with how this has been handled overseas, but my guess is just doing smart DME tuning but ultimately leaving some low-end power on the table.

Where'd you see the announcement about the 2025 JCW DCT? That's potentially pretty sweet if true and I wonder what box they're gonna use.

 

That's fair. I agree that tuning a DCT car, without the ability to make other mods not the least of which is a TCU tune, isn't perhaps the best path forward. But given all the 4th gen cars will have DCTs (bye bye manuals &#128549, it's probably the best possible chance that companies will start to modify the MINI DCT.

As for the move to all-DCT transmissions, MotoringFile mentions it in some of their articles about the 4th gen cars. Gone are the Aisin automatics, in for all models across the range (except BEVs, of course) are Getrag DCTs. The U25 Countryman is the first, which is basically a mechanical twin of the new X1 that's been out for 2(?) years now, with the M35i (aka BMW's version of the JCW) hitting dealers now or soon if I recall correctly.