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Will the ME have a DCT

 
Old 12-26-2017, 06:48 PM
  #161  
rgregory
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Originally Posted by lostsoul View Post
We have allot in common.....

Your just more successful at it





Very nice
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Old 12-30-2017, 10:31 PM
  #162  
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Well,
Maybe I should add my opinion since I own a 2018 M4 and 2017 SS Camaro(A8).

Actually, the Camaro is my sonís new car and I just bought my daughter the M4 for Christmas. The BMW is really odd when getting the car to move. In fact It can be very jerky when parking or having to inch the car forward/backward. The car engages the clutch upon acceleration(depressing the pedal). Iím not impressed with the control in respects to the clutch engagement. The shifts are definitely quick, but I think my sons car shifts just as quick. Iím not referring to the speed for reaction relative to the paddles. Without a doubt the BMW is instantly on the paddle pull. However, I think the Camaroís A8 actual shift time is just as good if not better. The Camaro has some upgrades, the 1LE wheels and Pilot sports provide good traction. After flooring the A8 and activating Performance Shift the car bangs the shifts. To, me the car shifts harder than the M4. The M4 has the competition package and that is in the Track mode.
On a side note the steering of the M4 is amazing and the car drives like a go kart. The vision is spectacular and seats are great. As the rags say, itís a drivers car and it really is. Itís a girls car compared to me sons.
The Camaro has a cat delete with duel mode exhaust and in the sound department destroys the M4.
Back to the tranny, the M4 has confirmed my choice for the M7 in my soon to be ZR1.
I will post pictures later
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Old 12-31-2017, 08:34 AM
  #163  
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Originally Posted by randyn View Post
Well,
Maybe I should add my opinion since I own a 2018 M4 and 2017 SS Camaro(A8).

Actually, the Camaro is my son’s new car and I just bought my daughter the M4 for Christmas. The BMW is really odd when getting the car to move. In fact It can be very jerky when parking or having to inch the car forward/backward. The car engages the clutch upon acceleration(depressing the pedal). I’m not impressed with the control in respects to the clutch engagement. The shifts are definitely quick, but I think my sons car shifts just as quick. I’m not referring to the speed for reaction relative to the paddles. Without a doubt the BMW is instantly on the paddle pull. However, I think the Camaro’s A8 actual shift time is just as good if not better. The Camaro has some upgrades, the 1LE wheels and Pilot sports provide good traction. After flooring the A8 and activating Performance Shift the car bangs the shifts. To, me the car shifts harder than the M4. The M4 has the competition package and that is in the Track mode.
On a side note the steering of the M4 is amazing and the car drives like a go kart. The vision is spectacular and seats are great. As the rags say, it’s a drivers car and it really is. It’s a girls car compared to me sons.
The Camaro has a cat delete with duel mode exhaust and in the sound department destroys the M4.
Back to the tranny, the M4 has confirmed my choice for the M7 in my soon to be ZR1.
I will post pictures later
Sounds like daddy's little girl gets more expensive presents..(kidding)

I'm sure they are both good kids.

I drove the camaro A8 and it helped me decide not to buy an A8 transmission.

Maybe the next gen corvette will have a better choice.

I do respect your insight and opinion. Thank you for your insights even if I disagree. The Porsche PDk I drove was flawless. I'd prefer that over a traditionaltorque convertor automatic at this time .

Otherwise a manual transmission is fine.

I'll test drive all transmission options before buying a c8

Last edited by JerriVette; 12-31-2017 at 08:35 AM.
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Old 12-31-2017, 09:51 AM
  #164  
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The M4 would be great driving on a track with two hands and pulling gears. The steering rate is so minimal that it is ideal for two handed driving. Iím so used to driving a stick so Iím most comfortable with one hand on the wheel and one on the shifter. My previous Z06 and 911 Turbo were manual. Hell, even my first car SD 455(shows my age) I drove with one hand on T400 auto slap shifter.

Most at people have not driven these automated manual transmission cars. They are simply manual transmissions that automatically engage the clutch without the control of a clutch pedal. Yes, you get the advantage of automatic shifts but lose precise control of the clutch. In my opinion in daily driving parking and stop and go traffic tends to make the experience in my opinion awkward. When backing up in a parking lot inching close to a car, i just donít like. You donít ride the brake like an auto, or ride the clutch in a true manual. The car will not move unless you give it gas.
I suggest anyone who has not driven a car like this to go try It.
Iím not bashing it, just saying itís different!
👍
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Old 12-31-2017, 10:00 AM
  #165  
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Originally Posted by randyn View Post
Most at people have not driven these automated manual transmission cars. They are simply manual transmissions that automatically engage the clutch without the control of a clutch pedal. Yes, you get the advantage of automatic shifts but lose precise control of the clutch. In my opinion in daily driving parking and stop and go traffic tends to make the experience in my opinion awkward. When backing up in a parking lot inching close to a car, i just donít like. You donít ride the brake like an auto, or ride the clutch in a true manual. The car will not move unless you give it gas.
I suggest anyone who has not driven a car like this to go try It.
Iím not bashing it, just saying itís different!
👍
There are some rumors that the C8 will include a TC in their DCT that would only be engaged at very low speeds. This would eliminate the issues that you are referring to and would provide that last bit to complete the illusion of driving a regular automatic.
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Old 12-31-2017, 10:33 AM
  #166  
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Originally Posted by randyn View Post
The M4 would be great driving on a track with two hands and pulling gears. The steering rate is so minimal that it is ideal for two handed driving. Iím so used to driving a stick so Iím most comfortable with one hand on the wheel and one on the shifter. My previous Z06 and 911 Turbo were manual. Hell, even my first car SD 455(shows my age) I drove with one hand on T400 auto slap shifter.

Most at people have not driven these automated manual transmission cars. They are simply manual transmissions that automatically engage the clutch without the control of a clutch pedal. Yes, you get the advantage of automatic shifts but lose precise control of the clutch. In my opinion in daily driving parking and stop and go traffic tends to make the experience in my opinion awkward. When backing up in a parking lot inching close to a car, i just donít like. You donít ride the brake like an auto, or ride the clutch in a true manual. The car will not move unless you give it gas.
I suggest anyone who has not driven a car like this to go try It.
Iím not bashing it, just saying itís different!
👍
What car is it that the DCT is so bad? I don't doubt your story but I would like to suggest you go test drive a Porsche with their version of the DCT, their PDK. It has none of the annoyances that you have experienced.
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Old 12-31-2017, 11:35 AM
  #167  
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2018 BMW M4

car is new with 100 miles. Itís not terrible, just different.

[img]webkit-fake-url://e71caf15-7bb0-48a4-bab2-0e46a4b95302/imagejpeg[/img]

the camaro

[img]webkit-fake-url://7fe02803-cf9a-4a46-be46-da4000647111/imagejpeg[/img]
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Old 12-31-2017, 01:25 PM
  #168  
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The PDK-S in the GT3/RS is as good as it gets, a better and more seamless experience than the current F80 M3/4.
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Old 12-31-2017, 01:35 PM
  #169  
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Originally Posted by rgregory View Post



Believe what you want...
Both of these "toys" earns a big:

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Old 12-31-2017, 03:03 PM
  #170  
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The Porsche box is very good. Unfortunately, we won't be getting that exact unit, along with the controls, in the C8. Most folks here are hung up on transmission architecture as the primary concern (DCT versus DCT/TC versus planetary) when in fact, any of these architectures can be made, or broken, by the mechatronics and controls.

With GM's history of over-constraining their designs while sharing costs and functions over multiple platforms, I hope the C8 transmission, whatever it may be, serves as a step up instead of a new set of compromises.

Last edited by RedLS6; 12-31-2017 at 03:17 PM.
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Old 12-31-2017, 07:04 PM
  #171  
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Originally Posted by ByByBMW
What car is it that the DCT is so bad? I don't doubt your story but I would like to suggest you go test drive a Porsche with their version of the DCT, their PDK. It has none of the annoyances that you have experienced.
The Audi we had behaved exactly as he described as well. Once you were underway it shifted nice. Buy in stop and go NYC traffic it wasn't all that pleasant.
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Old 01-01-2018, 12:32 AM
  #172  
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Originally Posted by ByByBMW View Post
What car is it that the DCT is so bad?











Now you see why I need a $65K and under c8.. dont let me die only knowing this in my life
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Old 01-01-2018, 08:36 AM
  #173  
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Originally Posted by NY09C6 View Post
The Audi we had behaved exactly as he described as well. Once you were underway it shifted nice. Buy in stop and go NYC traffic it wasn't all that pleasant.
Which Audi?
I love our A6 but it isn't a DCT and Audi is going back to TC's in some of their lineup.
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Old 01-01-2018, 12:09 PM
  #174  
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Originally Posted by RedLS6 View Post
The Porsche box is very good. Unfortunately, we won't be getting that exact unit, along with the controls, in the C8. Most folks here are hung up on transmission architecture as the primary concern (DCT versus DCT/TC versus planetary) when in fact, any of these architectures can be made, or broken, by the mechatronics and controls.
Pretty much an obvious statement. However, mechatronics and controls will never make a planetary transmission function acceptably when using paddles to downshift. (Can't make a silk purse out of a sow's ear!)
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Old 01-01-2018, 01:23 PM
  #175  
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Originally Posted by PurpleLion View Post
Pretty much an obvious statement. However, mechatronics and controls will never make a planetary transmission function acceptably when using paddles to downshift. (Can't make a silk purse out of a sow's ear!)
If you want to get into the realm of "never", then why not, from an engineering standpoint?



What we normally get from the automakers isn't always what the engineers wanted to build, instead it's a compromise for all platforms and costs. Planetaries are such, as are DCT trannies. The Porsche box is a very targeted unit. I'd like to see GM focus on targeting their C8 DCT to a very high performance level to match. This hasn't always been the case in the past, and the letters "DCT" alone don't guarantee performance with no compromises, but they certainly help pave the way for it in some areas.

One area where a planetary may never beat a DCT is in efficiency. A DCT architecture beats the planetary in most cases here considering the two biggest parasitic loss cases, which are oil pumping losses and drag torque in a planetary arrangement.

Last edited by RedLS6; 01-01-2018 at 01:56 PM.
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Old 01-01-2018, 04:04 PM
  #176  
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Originally Posted by RedLS6 View Post
One area where a planetary may never beat a DCT is in efficiency. A DCT architecture beats the planetary in most cases here considering the two biggest parasitic loss cases, which are oil pumping losses and drag torque in a planetary arrangement.
Exactly, thank you, you are making my case for me!

I believe that I read somewhere that GM is considering adding a limited use TC for very low speed operation to eliminate the jerkiness that occurs from 0 -5 mph? Thereby turning a DCT into a pretty bullet proof "automatic".
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Old 01-01-2018, 04:13 PM
  #177  
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We've owned 4 cars with a DCT, none of them have had this creep/slow speed issue.


Audi addressed it in '14 MY and since then does not exist.

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Old 01-01-2018, 05:37 PM
  #178  
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Originally Posted by PurpleLion View Post
Exactly, thank you, you are making my case for me!
.
You haven't made much of a case yet. In any event, I've been arguing the technical advantages and tradeoffs of both sides. If you understand both sides, you can envision where the future DCT architectures are trying to go.

Incorporating a TC has been done; it's a way to get around starting headaches. Some manuals and DCTs are torque limited due to the first gear tooth mesh area, which explains one reason why many of these transmissions do not have as low of a first gear as a planetary. When you add a TC to a DCT, the engineers have to account for any added torque placed on the lower gears (and bigger stronger gears add weight). But, the launch capability of a TC is hard to beat.


Originally Posted by Redls6
If you want to get into the realm of "never", then why not, from an engineering standpoint?
.

Last edited by RedLS6; 01-01-2018 at 06:03 PM.
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Old 01-01-2018, 06:05 PM
  #179  
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Originally Posted by PurpleLion View Post
Pretty much an obvious statement. However, mechatronics and controls will never make a planetary transmission function acceptably when using paddles to downshift. (Can't make a silk purse out of a sow's ear!)
The beauty for GM to create a planetary gearbox is that is what they presentlyhave their factories designed to build so the move to a planetary gearbox without a torque converter is realatively inexpensive Andy easy. Having driven a Mercedes Sl63 with its planetary gearbox without the torque converter I was impressed with the paddle response. Of course it had a renntech tune but I'd find it acceptable in the c8

Planetary gearboxs do have the ability to more easily package 10 speeds where a dct is limited in that regard and keeping the gearbox strong enough to handle massive low end torque.

Audi and BMW are moving away from dct to planetary torque converter gearboxes for a good reason even in their sports models.

I want a dct in the c8 but it's not that big a deal as long as manuals are available.

I'd prefer a dct but what will be will be.

The direct driving low throttle response of a dct and a manual are more fun than a torque converter automatic.

That said..how fast a person can downshift with paddles isn't really that big a deal other than it makes the car more fun to drive.

It would be nice if GM could get that concept beyond track time into their mission statement for the next corvette.

Btw the fuel efficiency of a ten speed torque converter automatic like in the ZL1 would be superior to a seven speed dct.not that it matters but that logic has BMW making its M5 and audis S5 utilize a torque converter automatic instead of the previously used dct.

I think the maintaince and repair as well as low speed jerkiness had something to do with that corporate decision as zf has improved the torque converter automatic beyond what was previously thought possible.

I haven't read a review yet that stated the new M5 with its torque converter automatic is a step backwards from its dct ...from a drivers standpoint

That was a shocker ..
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Old 01-01-2018, 10:51 PM
  #180  
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Originally Posted by RedLS6 View Post
You haven't made much of a case yet.
My point is very simply that there are intrinsic differences to the different transmission architectures that no amount of "mechatronics and controls" can overcome.

I am not a transmission engineer, so I will "guess" that it is not feasible to make a transmission that runs on hydraulic pressure to shift exactly like one that uses servo controlled mechanical links.

Last edited by PurpleLion; 01-01-2018 at 11:07 PM.
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