Procede v5 7DCT shift/safety logic

[Calvin@Vishnu]

Hi guys
We've been working on this for a while. One of the problems we noticed when adding more torque to a 7DCT equipped car (either n54 or n55) is that the extra midrange torque can result in clutch slipping during full-throttle automatic downshifts. Depending on clutch/trans oil temp, this slippage can last a second or two where you notice the revs just float high without any vehicle acceleration. If it gets bad enough, an overtemp warning will appear on the dash sending the transmission in to a temporary safety mode were it wont even down/upshift for a few seconds.

So we added some logic that detects automatic downshifts and triggers a low boost mode until the clutch is fully engaged. Once engaged firmly, the Procede quickly transitions to full boost. Works like a charm. Downshifts are quick, slip-free and car takes off like a rocket.

(Similarly, the Procede will trigger a low power/boost mode if it detects transmission slippage in the middle of a pull.)

Below is demo video demo on our n55 DCT. Boost (0-20psi) is represented in the gas level gauge. Car is in regular D mode. For the first two pulls, all I did was stop on the gas and let the Procede+transmission control unit do the rest. On the third run, I tried to confuse the two by going 1/2 throttle to trigger a primary downshift and then quickly full throttle to trigger a secondary downshift before the primary downsnift was complete. Didn't miss a beat.

This feature has just been ported over to the n54 firmware but still a bit more testing to go. Anyone in the SF bay area have a n54 DCT car?

[TMR]

Ive been driving with this new firmware all day. And WOW is it smooth. Vishny guys did it again.

[RimasRS]

That's the answear why BMW doesn't offer 1M DCT

[RimasRS]

BTW when will be released full V5? I'm looking to buy it, maybe there will be group buy?

[MarkR171]

Will v4 owners get an update?

[bryans2k]

Does it have this problem in sport mode?

[Calvin@Vishnu]

Originally Posted by RimasRS

BTW when will be released full V5? I'm looking to buy it, maybe there will be group buy?

The new n55 maps/firmware was posted up last night: http://procedetuning.com/BMW/n55/dow...downloads.html

[Calvin@Vishnu]

Originally Posted by bryans2k

Does it have this problem in sport mode?

Yep.. it happens in either D or DS. Basically anything that builds boost and downshifts at the same time. Remember that the ZF transmission in the n54/n55 aren't rated at the same torque holding capacity as the ZF transmission in the M3. And the n55/n54 naturally make more torque. So without a clutch pack upgrade, it's best to be precautionary. And in this case, precautionary means faster shifting and better performance/drivability.

After running our n55 DCT 135 at the drag strip (a few months back) with drag tires+meth at 17psi, our transmission would overheat and through a fault/limp during launch. So these transmission aren't as abuse proof as the 6MT/6AT. And upgrading clutch packs isn't exactly cheap (labor+install is over $2500).

[Mrbig]

So what do we 335is owners do wen will we get an update ?

[daixloxbmw]

Originally Posted by Calvin@Vishnu

The new n55 maps/firmware was posted up last night: http://procedetuning.com/BMW/n55/dow...downloads.html

What is new with V5?

I currently have the N55 V4 and wanted to know if its worth upgrading to V5.

[scott135i]

Not surprising for the DCT - good fix...

[Calvin@Vishnu]

Originally Posted by daixloxbmw

What is new with V5?

I currently have the N55 V4 and wanted to know if its worth upgrading to V5.

Yes, worth it for sure. Persistent autotuning. Better boost/trans logic. Smoother boost mapping. More in-dash display options. More power as well.

[Calvin@Vishnu]

Here's a funny/sad out-take from two nights ago when i was doing another demo video of this DCT feature. I just happened to run over a grotesque pothole and slice a 2 inch long hole in my front passenger side tire. All captured on video :/

[MarkR171]

Just downloaded the v5 maps on the link... but before I do anything, just want clarification. Do we just follow the steps of your updating firmware videos and just use the "pro5v002.bin" file? Do we need to do anything with the "1-5 7DCT" etc. files?

Edit: Nevermind, the "1-5 7DCT.pcd" would be for the map update, yes?

[TN_3]

Originally Posted by MarkR171

Just downloaded the v5 maps on the link... but before I do anything, just want clarification. Do we just follow the steps of your updating firmware videos and just use the "pro5v002.bin" file? Do we need to do anything with the "1-5 7DCT" etc. files?

Edit: Nevermind, the "1-5 7DCT.pcd" would be for the map update, yes?

Yes.

[Calvin@Vishnu]

Originally Posted by MarkR171

Just downloaded the v5 maps on the link... but before I do anything, just want clarification. Do we just follow the steps of your updating firmware videos and just use the "pro5v002.bin" file? Do we need to do anything with the "1-5 7DCT" etc. files?

Edit: Nevermind, the "1-5 7DCT.pcd" would be for the map update, yes?

Yep! The .bin file is the firmware file. And the .pcd is a map file. The Procede software wont recognize the wrong file so nothing to worry about.

[scott135i]

Originally Posted by Calvin@Vishnu

Here's a funny/sad out-take from two nights ago when i was doing another demo video of this DCT feature. I just happened to run over a grotesque pothole and slice a 2 inch long hole in my front passenger side tire. All captured on video :/

Nice vid. I know that feeling all too well.

Ps. Get gas. You're on E.

[cwg]

Can anyone refer me to a good technical write up or discussion on how the BMW DCT actually works. All I have been able to find is fluff and generalities. Thanks and sorry if I missed an earlier thread which covered this.

[MarkR171]

Originally Posted by cwg

Can anyone refer me to a good technical write up or discussion on how the BMW DCT actually works. All I have been able to find is fluff and generalities. Thanks and sorry if I missed an earlier thread which covered this.

Video from ZF of their DCT, though I think the 135/M3 uses a Getrag made DCT

edit: I think this is actually the transmission built for Porsche's PDK though BMW's DCT is essentially the same principle.

[cwg]

Thanks very cool video

I scrolled through the avaialble videos - I think ours is the ZF 7 dtc 50 - it has its own video. it says max torque input is 520 Nm

[MarkR171]

Does ZF make our transmission? Wiki says Getrag does.

[cwg]

Originally Posted by Calvin@Vishnu

Yep.. it happens in either D or DS. Basically anything that builds boost and downshifts at the same time. Remember that the ZF transmission in the n54/n55 aren't rated at the same torque holding capacity as the ZF transmission in the M3. And the n55/n54 naturally make more torque. So without a clutch pack upgrade, it's best to be precautionary. And in this case, precautionary means faster shifting and better performance/drivability.

After running our n55 DCT 135 at the drag strip (a few months back) with drag tires+meth at 17psi, our transmission would overheat and through a fault/limp during launch. So these transmission aren't as abuse proof as the 6MT/6AT. And upgrading clutch packs isn't exactly cheap (labor+install is over $2500).

The Vishnu guys say its ZF in their post