135 DCT Owners

[Evice]

I read this question in Porsche forums and wanted to ask here.

Does your DCT behave the same way ?

If you hold the paddle in when you release it the PDK will select the lowest gear possible for the released speed, same as up-shifting if you hold it will select the highest gear for the speed you are at.

Thanks!

[MarkR171]

Never tried it... I'm eating breakfast right now but I'll give it a shot in about an hour and post again

I have a feeling it might, even the 7sp auto in my previous Mercedes did that.

[XCC Motorsports]

I haven't tried this either. Interesting.

[MarkR171]

Gonna go for a drive now, will report back in 30min max

[MarkR171]

Originally Posted by MarkR171

Gonna go for a drive now, will report back in 30min max

Oops, as always, I extended my drive, hard not to do with this car.

Anyway, no, it will not select the lowest possible gear for you when you hold the downshift paddle or downshift on lever. I was disappointed at first until going into a turn at 40mph in 6th gear and clicking the paddle quickly 3 times fast and the car rev matched into 3rd instantly.

I think they didn't bother programming the hold downshift function because it's faster to just click multiple times to select the gear you want. I drove some empty backroads spiritedly and did multiple 6-3, 5-3, 4-2 gear changes and everything was flawless. Even more happy with the DCT now

[Artz 330]

doesnt your DCT have a click in the accel pedal. I forget what its called but with the padel shift on my auto 335 it has a click in the pedal almost all the way in that after that click it auto downshits to lowest gear possible.... is that still the case?

[MarkR171]

Well yes, there's the kickdown, but that's in auto mode. Kicking the pedal down in manual mode won't cause a gear shift.

[Trojan4evr]

I'm still getting used to DCT. so much fun.

[Evice]

I am disappointed. PDK engineers seems like they can think outside the box compared to the DCT engineers.

[TreDirtyFive]

Actually, it does on mine...so, YES. If I'm in M5 and slow down to 30 or so and click down it actually skips a few and goes straight to 3rd. Did so when I beat on it my European Delivery as well.

[MarkR171]

Originally Posted by TreDirtyFive

Actually, it does on mine...so, YES. If I'm in M5 and slow down to 30 or so and click down it actually skips a few and goes straight to 3rd. Did so when I beat on it my European Delivery as well.

You sure about that?

I tried multiple times at ~40mph in M5 and holding the downshift paddle. It downshifted to 4th and stayed there with the paddle still held. Double click lets it skip 5>3, triple click 5>2 etc. I think multiple clicks is faster than holding and waiting anyway so I'm happy.

Originally Posted by Evice

I am disappointed. PDK engineers seems like they can think outside the box compared to the DCT engineers.

They aren't thinking outside of the box. Mercedes' 7 speed slushbox in my previous '07 SLK (and pretty much all their cars) did the same thing if you hold the paddle/lever to downshift. You shouldn't be disappointed either. I've test driven a Cayman equipped with PDK so I'm aware of it's hold > skip gear function, but I actually prefer the double/triple click function of the BMW DCT. Pull > Hold takes more time than *click* *click.* Double click your mouse now and you'll see why. In the time it takes to double click a mouse, your transmission is down 2 gears. Now triple click your mouse, that's 3 gears. Pulling and holding the paddle is not as quick. Also, you know exactly what gear you're in since you know exactly how many gears you went down.

With the PDK or Mercedes system, you don't know how many gears it shifted down. As you get used to your car, you already know what gear is good for what speeds, so you don't need the computer to make that decision for you.

[Evice]

@Mark171: I see your point, however, PDK STILL has the ability to click-click-click...and from my perspective, if you breaking from 150 mph to 60mph for a turn on track, I can prefer DCT to it with a perfect match with single drop, rather than "possible" upsetting the car's balance in a braking zone, 2-3 times. Now, I know DCT/PDK etc is super smooth that you may not feel the gear changes, but it still is some kind of "upset" in overall balance of the car. Plus, I have a feeling that you can get back on throttle earlier than click-click-click, or worse at the same time. Don't know if it makes sense.

[MarkR171]

Actually, when you "click-click-click," only 1 gear change is made. It doesn't do each shift individually, so it won't upset the balance.

[GeeRam]

Originally Posted by Evice

I am disappointed. PDK engineers seems like they can think outside the box compared to the DCT engineers.

Well, to be fair, Porsche after all were the first to build an effective DCT transmission back in the early eighties.

[Evice]

Originally Posted by maxnix

So this seems to be an argument for leaving it in automatic mode, right?

No. clicky clicky manual.

Originally Posted by maxnix

Translation: Dual clutch transmission engineers can outhink dual clutch transmission engineers? Er, what?

Wake the f. up. That sentence means Engineers working on PDK vs Engineers working on DCT in 2 different companies. Are you trying to be idiot like this on purpose?

Originally Posted by MarkR171

Actually, when you "click-click-click," only 1 gear change is made. It doesn't do each shift individually, so it won't upset the balance.

I guess you are right, but I thought every click is possibly engaging to revving 2 gears, 1 up and 1 down, so I guess 2 total gear changes for 3 clicks?

[Evice]

Originally Posted by GeeRam

Well, to be fair, Porsche after all were the first to build an effective DCT transmission back in the early eighties.

Makes sense.

[MarkR171]

Originally Posted by Evice

I guess you are right, but I thought every click is possibly engaging to revving 2 gears, 1 up and 1 down, so I guess 2 total gear changes for 3 clicks?

Shifting 5>2 or 6>3 was just 1 rev match and shift. When I tried 7>3, you could hear it rev match twice and do 2 shifts.

[Evice]

Originally Posted by maxnix

No, but I think the author of the original garbled sentence was, or he was at least careless.

Still don't really grasp your point, if there is one.

It's like debating if angels should wear pink or white tutus.

There is nothing to debate on. It was a comment, and seems like only you have the ability to understand it as argument to discuss about. Now, silence please.

[DHA]

Originally Posted by MarkR171

Well yes, there's the kickdown, but that's in auto mode. Kicking the pedal down in manual mode won't cause a gear shift.

Do US cars not kickdown in manual? My UK car does, lots of people slate it for that but you can avoid it by not mashing the throttle to the floor in too high a gear.

[MarkR171]

That may be something I have to check again, DHA. You could be right.

[GaryS]

Originally Posted by MarkR171

Shifting 5>2 or 6>3 was just 1 rev match and shift. When I tried 7>3, you could hear it rev match twice and do 2 shifts.

As I understand it, you have one clutch for 1-3-5-7 and another clutch for 2-4-6-8, and it engages one clutch while it simultaneously disengages the other. So does that mean it shifts from odd to even gears or vice-versa with one engage/disengage and one blip, but it has to do the whole thing twice to shift between two odd gears or two even gears?

[MarkR171]

Originally Posted by GaryS

As I understand it, you have one clutch for 1-3-5-7 and another clutch for 2-4-6-8, and it engages one clutch while it simultaneously disengages the other. So does that mean it shifts from odd to even gears or vice-versa with one engage/disengage and one blip, but it has to do the whole thing twice to shift between two odd gears or two even gears?

I think you're right with the clutches being for odd or even gears, but in my experienced (and I've been playing with it a lot lately,) I don't notice a slower shift between 4>2 or 5>3 than if I did 4>3 or 5>4. The only difference is that extra click, which, if you double click your mouse, is equal to roughly .0001 seconds. I guess it's quick enough to engage the clutch, register you want to change 2 gears, and go into whatever gear you end up selecting in 1 shift instead of selecting a gear on the other clutch and making another change.

The same goes for 6>3 or 5>2 shifts. The only difference in shift time is that 3rd click, otherwise, 1 quick rev match and 1 gear change is made.

I think asking the transmission to downshift 4 gears is too much because of driver error. The driver can't click 4 times fast enough before the transmission already downshifted 3 gears down, so another one is made immediately after. Still very quick, just not smooth.

Use the kick down for anything more than 3 gears.

I have a GoPro HD... maybe I'll do a quick video, that will explain it a lot better.