Question about 8 speed auto

[mattkim85]

Soon to be a 650ix owner, had a quick question to anyone with experiences with the 8 speed auto and DCT.

When manually switching gears, is the 8 speed noticeable slower on the up/downshifts compared to the DCT?


Thanks for any input

[Mentos]

If you drive them back to back it will seem a little slower, but in return it will also feel smoother. After a day or so you adjust and the difference becomes negligible, I notice the smoothness more then the slightly slower shifts.

Obviously the mode you have the car in also makes a difference. In sport/sport+ the shifts are plenty fast enough that I don't miss a DCT/or any other auto clutch system. In comfort mode, since I'm after a smooth ride I'm glad I have the ZF. I honestly wouldn't have taken the DCT even if it was a free option. My car is a 640d, so the monstrous torque may play a part in my experience, but by all accounts I've read/heard from friends/etc I've yet to hear a negative word about the 8sp ZF. It really is a revelation for someone that's often found conventional autos clunky.

The only thing I don't like, is to meet economy targets from a standstill it will select 2nd. Usually I remember to flick down, but if not there's a slight pause as it switches to 1st when it realises I really want to take off, not just gradually move. It may be different in the US, as in the Uk we have extremely punitive taxes based on standardised emissions tests. Stop start and things like starting in 2nd help the car into a much lower tax band, making it more attractive to company car buyers.

[bjayfan]

Yes, the ZF is slower.

But, in the 6 the SAT is standard which is slightly different programming and the shifts will be a touch faster than the standard ZF (on the 5's the SAT is an option) and as said above, the ZF is considered one of the best in the industry. I don't think you'll be disappointed at all.

[ibimmer954]

I test drove a DCT in the 135i once. I'd also say the DCT shifted slightly faster. But not by much. As mentioned earlier, the 8AT is much smoother. When starting from a stop, I think the DCT has more clutch lag than the torque converter. That makes a big difference for fast starts.

With 8 speeds and the wonderful BMW engines, you have to click the downshift button many times to get any significant engine braking on hills. So if your goal is downhill engine breaking, be prepared for 4-5 clicks. It's pretty crazy.

[mattkim85]

Thank you

Yeah, now that I think about it, the DCT on my M3 is very clunky especially at low speeds. I guess this is also a regular automatic so it will roll off the line when I let go of the brake during drive mode?

But makes me wonder, is the DCT on M5 and M6's clunky as well?

[bjayfan]

Originally Posted by mattkim85

But makes me wonder, is the DCT on M5 and M6's clunky as well?

No, not at all.

[ibimmer954]

Originally Posted by mattkim85

Yeah, now that I think about it, the DCT on my M3 is very clunky especially at low speeds. I guess this is also a regular automatic so it will roll off the line when I let go of the brake during drive mode?

Yep, once the engine turns back on.

But makes me wonder, is the DCT on M5 and M6's clunky as well?

My short test drive, I felt the M5 DCT was reasonably smooth once you were moving. However, the combination of the engine starting plus the clutch kicking in made it tricky to start smoothly for me on the test drive. I'm sure I'd get used to it eventually, but it would take some practice.

[mattkim85]

I just hope the 8 speed's shift changes are fast enough for "spirited" drives. *crossing fingers

[bjayfan]

If you like to drive with the suspension a bit stiffer, set your sport mode to chassis only and use the buttons to the left of the shifter to put it in sport. When puttering around in town when you have it in Drive mode, after you learn to anticipate step down at low speeds you can simply move the shifter left and increase the revs and bypass the step down. You'll like the drive better and feel a bit more connected even in stop and go.

When you're carving simply go to sequential and enjoy, it really is pretty damn good.

[ibimmer954]

Originally Posted by mattkim85

I just hope the 8 speed's shift changes are fast enough for "spirited" drives. *crossing fingers

Yes, it will definitely be fast enough for that. I think the 8AT shifts amazingly fast.

Or just leave it in Sport Mode. The tranny will hold revs a lot higher in Sport mode if you are getting on the gas. All the way to the top if you'd like.

Remember though that 8 gears is a lot of gears. When you slow down to take a slow corner you will find yourself having to click 3 or 4 times. Might be faster just to let the Sport mode do its thing. I think it can shift directly from higher gears to lower gears without hitting the ones in between. You can't do that with the paddles. Maybe if you click the paddles fast enough, the tranny will do multi-gear jumps. Not sure.

[neversummer78]

Originally Posted by mattkim85

I just hope the 8 speed's shift changes are fast enough for "spirited" drives. *crossing fingers

I got heavy foot and always drive my car just how it was meant to be, and this 8 speed shifts brilliantly. It is unlike the automatic box from Mercedes which is more of making suggestion when manually shifting.

[mattkim85]

Originally Posted by Mentos

If you drive them back to back it will seem a little slower, but in return it will also feel smoother. After a day or so you adjust and the difference becomes negligible, I notice the smoothness more then the slightly slower shifts.

Obviously the mode you have the car in also makes a difference. In sport/sport+ the shifts are plenty fast enough that I don't miss a DCT/or any other auto clutch system. In comfort mode, since I'm after a smooth ride I'm glad I have the ZF. I honestly wouldn't have taken the DCT even if it was a free option. My car is a 640d, so the monstrous torque may play a part in my experience, but by all accounts I've read/heard from friends/etc I've yet to hear a negative word about the 8sp ZF. It really is a revelation for someone that's often found conventional autos clunky.

The only thing I don't like, is to meet economy targets from a standstill it will select 2nd. Usually I remember to flick down, but if not there's a slight pause as it switches to 1st when it realises I really want to take off, not just gradually move. It may be different in the US, as in the Uk we have extremely punitive taxes based on standardised emissions tests. Stop start and things like starting in 2nd help the car into a much lower tax band, making it more attractive to company car buyers.

Does the US models start off in 2nd gear as well?

And does the Auto Start/Stop feature turn on as a default?

[bjayfan]

Originally Posted by mattkim85

Does the US models start off in 2nd gear as well?

No, but then my experience with the ZF was in a 2011.

There are many that complain about this 'lurch on startup', blame it as starting in second, but it's actually step down. When coming to a stop, if you don't completely stop, then add a fraction of a second, the transmission never makes it to first. If you then hit the gas while still in 2nd, the transmission steps down, adding a delay and then a lurch as you have the pedal pressed for second, but in first you take off harder. It's just getting used to the behavior of the drive logic.

That's why I said above when driving in town in Drive mode, you can anticipate the step down and switch the transmission into sport by moving the shift lever left. That raises the revs and keeps you in a range that the step down isn't necessary.

As for Euro cars, have no idea. They could start in 2nd or it could be the same step down issue.

[wzj519]

Originally Posted by mattkim85

Does the US models start off in 2nd gear as well?

And does the Auto Start/Stop feature turn on as a default?

Both r right.
Mine is 2013, the auto star/go is default to turn on, but I heard 2014s have the option can set turn off as default. Not sure about it.
I have coded my vehicle, and default it to turn off.

[ibimmer954]

If the 8AT is not in Sport mode, it will most likely start in second gear. Once you push it to Sport mode (move the lever to the left), then it will start in first gear. That's how my car behaves anyway.

Punching the accelerator on my car in first gear makes it lose traction quickly. 20" RFTs.

[bjayfan]

Originally Posted by ibimmer346

If the 8AT is not in Sport mode, it will most likely start in second gear.

Different then over the years. Comfort/Normal/Sport/Sport+ all started in 1st if you were completely stopped. Sport and Sport+ rarely made it to 8th.

[wzj519]

Originally Posted by bjayfan

Different then over the years. Comfort/Normal/Sport/Sport+ all started in 1st if you were completely stopped. Sport and Sport+ rarely made it to 8th.

This is exactly I wanted to say.