[GoKimiGo!]

Originally Posted by demosthenes

Because we talking about transmissions and the DCT is an alternative for current 6MT and 6AT buyers. To make an informed choice, we need to understand the alternatives.

I am not implying the DCT and 6AT are similar. They are completely different.

I understand, but that is a whole new can of worms. If there isn't already a thread on the topic that would warrant one.

But a loss of power and a loose, disconnected or even slipping feel has always been associated with mass market automatic torque converter transmission.

That is a big reason why I have always driven a manual transmission since day one of my driving days. The other being true manual gear selection.

However, DCTs are manual gear boxes with an automated function. There is no power loss penalty, if anything power delivering has the sensation of being more immediate and linear. True manual gear selection is ready when you are as is the ability to just cruise along without thinking much.

It is still very much involving to drive in manual mode. I would own one in a heart beat.

[GoKimiGo!]

Originally Posted by demosthenes

There is more drivetrain loss in the torque converter while shifting, but once the tranny is locked up, there is no additional loss, correct?

Theoretically, one issue is the slippage that occurs between shifts. The other involves the epicyclic (planetary) gears used by traditional automatic transmissions.

Though a lot of technology has gone into making automatics much better than they used to be, there is a threshold of performance that they just can't get passed due mainly to their inherent design.

[captainaudio]

Originally Posted by GoKimiGo!

Theoretically, one issue is the slippage that occurs between shifts. The other involves the epicyclic (planetary) gears used by traditional automatic transmissions.

Though a lot of technology has gone into making automatics much better than they used to be, there is a threshold of performance that they just can't get passed due mainly to their inherent design.

Tell that to AMG or Bentley. The new Bentley Continental GT Supersports has a ZF 6 speed Automatic (with a torque converter). It weighs 5,000 lbs has 600hp, 600lb/ft. of torque and does 0-60 in 3.7 seconds.

There is just a lot of misinformation being thrown around here. The torque converter in the 335 Steptronic is almost always locked up and it does not come into play above 10MPH or so. Also in manual mode the driver has full,control over gear selection unless there is a situation that will damage (overrev) the engine. So the car won't let you do something dumb and blow the engine. I guess that is in a way a 'loss of control'.

CA

[captainaudio]

Originally Posted by demosthenes

There is more drivetrain loss in the torque converter while shifting, but once the tranny is locked up, there is no additional loss, correct?

Correct, and the torque converter in the ZF is always locked up unless the car is going less than 10MPH. Some of the newer ZF designs that are about to be released do not even have a torque converter but use multi plate clutches.

CA

[galahad05]

Note how the 335 gets higher mpg with the auto vs the 6 speed manual, EPA cycle....

[e90-ZeRo]

Originally Posted by tuned2ride

Automatic is good enough. The Steptronic's interface is one of the best (if not the best) in the industry.

I was a die-hard fan for manuals. After many automatic, the Steptronic is the first to change my mind. In manual mode, you can control the engine as much as you want, it is as fun as a manual and there is no drawback.

I don't miss that 3rd pedal.

Question about Steptronic;

When i'm shifting, should I let go of the gas, let it shift, and then press it again or is this something I can just mindlessly keep my foot on the gas while tipping the thing up and down?

[captainaudio]

Originally Posted by TyPe-ZeRo

Question about Steptronic;

When i'm shifting, should I let go of the gas, let it shift, and then press it again or is this something I can just mindlessly keep my foot on the gas while tipping the thing up and down?

It is not necessary to take your foot off the gas while shifting.

CA

[Verbiage]

Originally Posted by captainaudio

Tell that to AMG.

There is just a lot of misinformation being thrown around here. The torque converter in the 335 Steptronic is almost always locked up and it does not come into play above 10MPH or so. Also in manual mode the driver has full,control over gear selection unless there is a situation that will damage (overrev) the engine. So the car won't let you do something dumb and blow the engine. I guess that is in a way a 'loss of control'.

CA

Yes, this was one of the things I noticed about this transmission. If there is danger of over-revving, then the engine will not allow the gear change.

Originally Posted by TyPe-ZeRo

Question about Steptronic;

When i'm shifting, should I let go of the gas, let it shift, and then press it again or is this something I can just mindlessly keep my foot on the gas while tipping the thing up and down?

No need to let go of the gas, as the Steptronic transmission does not require the disengaging of the engine (and the stoppage of engine rotation) to switch gears. It's more of an automated manual transmission.

[stressdoc]

The answer to the OP's Q should get resolved if Shiv gets a 335is.

Otherwise, I don't think any of us would be needing any repairs on a DCT short of 100k miles.

If I were buying a new BMW this year, and my wife adamantly tells me that we are not, it would be a 335is with DCT. Freude am fahren. All my bimmers have been manual trannys, back to my first, a 4speed 1602ti. Never could see spending all that $ for an auto. But now I would pony up for the DCT. At $1500 clams it seems a relative bargain. I would miss the delight of feathering a clutch, feeling the tires bite and slip. But there are new joys in life, and nanosecond shifts are one of them. Expensive? Yes. Complex? Yes. Likely to disappear when the 8speed step takes over? Maybe.

[montreal red]

i am sure the cost of a new clutch on a DCT will go down eventually when they become more common among bmws (not just the performance oriented ones)... when this happens, maybe i'll switch to DCT as well. for now, 6MT is just cheaper to maintain and easier to deal with. new technology always takes time to sort out their quirks and for prices to settle...

[demosthenes]

Originally Posted by captainaudio

Correct, and the torque converter in the ZF is always locked up unless the car is going less than 10MPH. Some of the newer ZF designs that are about to be released do not even have a torque converter but use multi plate clutches.

CA

Thanks CA. I've got 2 follow up questions.

1. If a 6mt, 6at and dct had the same gearing, and we jumped on them in 2nd gear at 30 mph, would they accelerate the same?
2. Why is 6at slower 0-60 than the 6mt, even though the 6at has ~12% gearing advantage?

Thanks.

[RX7guy]

I will drive a manual unless I become an amputee

You guys can smoke me at the next intersection in 2035 with your 11-speed quad clutch car that shifts in 0.00001 seconds. I won't care

[Tallest]

i wouldnt use them as a benchmark. those guys dump the clutch and practice launch control. So in real life of lazy armchair race driver it will last fine.

but i guess it's supposed to be one of those cars you can track - and that is bad if it breaks down so quickly.

[GoKimiGo!]

Originally Posted by captainaudio

Tell that to AMG or Bentley. The new Bentley Continental GT Supersports has a ZF 6 speed Automatic (with a torque converter). It weighs 5,000 lbs has 600hp, 600lb/ft. of torque and does 0-60 in 3.7 seconds.

There is just a lot of misinformation being thrown around here. The torque converter in the 335 Steptronic is almost always locked up and it does not come into play above 10MPH or so. Also in manual mode the driver has full,control over gear selection unless there is a situation that will damage (overrev) the engine. So the car won't let you do something dumb and blow the engine. I guess that is in a way a 'loss of control'.

CA

Yes, it is locked up after 10MPH. However the much more complex design means there are many more parts. As always the more moving parts you have, the more energy is required to moved them and that equals more drive train loss. Dyno two vehicles with the same output with both a manual and an automatic transmission and the manual will read slightly higher.

But there are so many variables such as gearing that make it difficult to compare one variant to the other many of times going on claimed 0-60 or 1/4 miles times.

Also If we may think about it in terms of performance on different terms. I am aware of traditional automatics being able to hold a lot of power, many drag racers prefer automatics for many reasons.

The problem becomes putting down that power over a long period of time in various load conditions. For example on a road course. The complexity of an automatic transmission as I am sure you know is much more intricate than the simplicity of a manual transmission. That being said, long periods of abuse tend to have adverse effects on the clutches and bands. As an example, for drag racers it can work well since it is a few seconds of abuse and not a sufficient amount of time to work too much heat into the components. Even still a lot of them do rebuilds every year or two depending on how actively they race just as an upkeep.

It works for a Mercedes or a Bentley with gobs of power because they will always be mainly used for cruising with the occasional dipping of a heavy foot. I have never seen a Bentley on a road course and very few Mercs. It can be done, but those cars just aren't built with that purpose in mind, even the C63 AMG is not really fit as a track machine.

For a car like an M3 which many weekend warriors take out to their local road course. The long lengths of time spent under load are in my opinion too much for a traditional automatic transmission to handle given its design.

I am not saying it can not be done, but there has to be a reason that no one does in any form of motorsport other than drag.

I am not against any particular technology, I can see all the pros and cons for given personal needs of each driver. I don't think I am misinformed though, but I have been wrong in the past.

[ianthegreat]

Originally Posted by Bavarian III

Be careful, you are asking for it saying things like that on this board

It's almost as bad as insulting those titanium silver guys :rolleyes:

[cotmfk]

Youch, that price is steep!

[ianthegreat]

Originally Posted by TrackRat

A DCT uses the same types of gears and internal layout as a manual trans. So no it's not an auto trans. It might be an "auto" to you, but technically it's actually a manual trans. with computer control.

What people chose to drive is a personal choice but a DCT and MT are both manual transmissions without planetary gears. You could always install a third pedal with spring that isn't attached to anything if it makes you feel better?

au⋅to⋅mat⋅ic  /ˌɔtəˈmætɪk/ Show Spelled Pronunciation [aw-tuh-mat-ik] Show IPA
Use automatic in a Sentence
See images of automatic
Search automatic on the Web
1. done unconsciously or from force of habit; mechanical: an automatic application of the brakes.

Do the gears automatically change? Yes. Automatic.

man⋅u⋅al  /ˈmænyuəl/ Show Spelled Pronunciation [man-yoo-uhl] Show IPA
Use manual in a Sentence
See images of manual
Search manual on the Web
–adjective 1. done, operated, worked, etc., by the hand or hands rather than by an electrical or electronic device: a manual gearshift.

Do I operate the gears independently? Yes. Manual.

[ianthegreat]

Originally Posted by TyPe-ZeRo

Question about Steptronic;

When i'm shifting, should I let go of the gas, let it shift, and then press it again or is this something I can just mindlessly keep my foot on the gas while tipping the thing up and down?

Nope, your faux-manual does all the work for you.

[captainaudio]

Originally Posted by GoKimiGo!

Yes, it is locked up after 10MPH. However the much more complex design means there are many more parts. As always the more moving parts you have, the more energy is required to moved them and that equals more drive train loss. Dyno two vehicles with the same output with both a manual and an automatic transmission and the manual will read slightly higher.

But there are so many variables such as gearing that make it difficult to compare one variant to the other many of times going on claimed 0-60 or 1/4 miles times.

Also If we may think about it in terms of performance on different terms. I am aware of traditional automatics being able to hold a lot of power, many drag racers prefer automatics for many reasons.

The problem becomes putting down that power over a long period of time in various load conditions. For example on a road course. The complexity of an automatic transmission as I am sure you know is much more intricate than the simplicity of a manual transmission. That being said, long periods of abuse tend to have adverse effects on the clutches and bands. As an example, for drag racers it can work well since it is a few seconds of abuse and not a sufficient amount of time to work too much heat into the components. Even still a lot of them do rebuilds every year or two depending on how actively they race just as an upkeep.

It works for a Mercedes or a Bentley with gobs of power because they will always be mainly used for cruising with the occasional dipping of a heavy foot. I have never seen a Bentley on a road course and very few Mercs. It can be done, but those cars just aren't built with that purpose in mind, even the C63 AMG is not really fit as a track machine.

For a car like an M3 which many weekend warriors take out to their local road course. The long lengths of time spent under load are in my opinion too much for a traditional automatic transmission to handle given its design.

I am not saying it can not be done, but there has to be a reason that no one does in any form of motorsport other than drag.

I am not against any particular technology, I can see all the pros and cons for given personal needs of each driver. I don't think I am misinformed though, but I have been wrong in the past.

I agree that the Step type automatic is rarely seen in road racing, but look at the number of people in this thread who have manuals and never track their car. My point is that for the way most BMWs are used the advantages to a DCT over a traditional automatic are more theoretical than real.

If you are a serious track junky there is no car that BMW makes with any type of transmission that is suitable for anything but casual track use.

CA

[Jeff@TopGearSolutions]

Originally Posted by car62

Those car magazine test cars get beaten to death. Probably the clutches last much longer being driven sanely by someone who actually owns the car and is paying their own money to drive it.

This logic holds no water. Its an "auto-like" transmission. (Design is manual like, without the input of manual operation, thus auto-like).

There is a gas pedal and brake pedal just like any other auto car.

The driver no matter how aggressive or subtle, cant provide any "Abnormal" wear from slipping the clutch or driving aggressive.

It is what it is..... it wears out from use, however, unlike an MT, with this transmission you have no choice to what extent and amount it wears out as it does everything mechncially with no driver input needed.

You can get a brand new 6MT and wear out the clutch the first day, or better subtle drivers will have it wear out in a 100K. <--- Dependent on the driver

This transmission wear is PARTIAL at best in terms of the driver, and moreso because of its design.

The fact that you guys are EXCUSING this failure at 40,000 because of driver is rediculous.. again, the user cant purposely provide any additional wear from driving the car like it should be driven. If it cant take the heat,(then get out of the kitchen) then they need to look into a better design.
I'm complicating the situation more then it really is, but my main point is I dont care whos driving, it still wore out pretty fast.

I know there will be a select few of people that disagree, and thats fine. But at the end of the day, how much abnormal wear can you input from driving the car like it should? I ripped around my last car, and doubled the stock power to the wheels and still ran on a stock clutch for 65K miles... Driver mod? I think so. Its not like C and Driver put 40,000 miles on the car going down a 1/4 mile drag strip all day. They had to be driving on the highway a majority of the time.

[technik330]

I've always owned manual transmission cars, see sig, and have never considered leaving them; although the thought is all too often crossing my as of recently.

I've driven in bumper to bumper traffic (manual trans), moving 1-3 feet at a time, for several hours at a time, and it can be quite a chore. A manual transmission is rewarding, but to how much of extent?

I believe DCT can be summed up as "fast" gear changes, with flawless accuracy.

Who wouldn't want that?

I love to heel/toe as much as any other enthusiast; however for the handful of times I get to do it daily versus...lumbering in bumper to bumper traffic, the dct seems to win, by combining the best of both worlds.

I'd have to test a 335iS with DCT before I do give up a 6 Speed, in the end...

[335e92tx]

Originally Posted by captainaudio

On a track the speed of a shift is not that important to lap times. What is important is the ability to left foor brake and the fact that a perfectly rev matched down shift can be accomplished with both hands on the wheel.

Bingo
The track day I had about a year ago involved a porsche cayman going through a fence and a S2000 that went end over end. Its much more complicated to make sure you get every turn entry/exit right when you have to take your hand off the wheel to downshift/upshift (not to mention clutch release). You just probably increased the chances of a yard sale by 3 times if you don't do it VERY often and are driving a manual.

Tell yourself you will go faster - unless you practice it very often your just fantasizing yourself as a real car racer and will likely have a reality check before long.