How do DCTs work?
#61
I know it isn’t a good comparison as far as smoothness and working.
Gallardo will stay in first gear as long as your foot is on the brake, it is a safety thing not clutch wear. It will disengage 1st if you leave your foot off the brake so that you don’t accidentally accelerate thinking in neutral. I never drive mine in auto mode and my first clutch was replaced at 24k and the 2nd one is still going now at 61k.
I know a number of guys that had the same experience with the early model and premature clutch wear.
I sold mine at 18k miles so not sure how much wear was left on the replacement clutch but I was told by Lamborghini service that there were software update done that extended the life of the clutch.
I also recall reading that you put car in neutral when approachING a stop rather than down shift which I am sure helps.
One other thing you mention was taking your foot of the accelerator while performing a shift.
That another difference between the Egear and the Getrag in my 458. Per the Ferrari owner manual is specifically tells you NOT to take your foot of the accelerator during up or down shift.
I believe that has something to do with the algorithm and software but can't be sure.
I just remember reading that was one of the thing you attribute to the long life of your egear clutch.
I can tell you I never lifted as I felt that defeated the purpose of the egear and it's quite shifts.
But sound like you have found the formula to getting acceptable clutch life with the egear setup.
#62
Le Mans Master
Originally Posted by vetteLT193
Mine also feels like a manual transmission even in auto mode... which is why Acura has the DCT with the Torque Converter.... DCT's don't drive all that well in some conditions but are great when driving fast. The TC allows a smoother operation, and more importantly, a more expected result (i.e. the car starts rolling when you take your foot off the brake, won't roll backwards on mild hills, etc.)
Last edited by NY09C6; 12-03-2018 at 06:25 PM.
#64
Melting Slicks
I agree. GM will absolutely go the same route Acura did. The average new Corvette buyer won't put up with what BMW, etc. buyers do.
#66
Melting Slicks
The problem is you are wrong. This concept may blow your mind but you can tap the paddles quickly multiple times and the DCT will skip gears and still do it faster than you can manually... I know mine does exactly this. Mine also feels like a manual transmission even in auto mode... which is why Acura has the DCT with the Torque Converter.... DCT's don't drive all that well in some conditions but are great when driving fast. The TC allows a smoother operation, and more importantly, a more expected result (i.e. the car starts rolling when you take your foot off the brake, won't roll backwards on mild hills, etc.)
A DCT is very much a manual transmission with an automated clutch pedal. The paddles let you shift just like you would in a manual. The reason they don't just give a manual gear lever to pick whatever gear is that would be stupid... you can keep both hands on the wheel and shift faster with the paddles.
A DCT is very much a manual transmission with an automated clutch pedal. The paddles let you shift just like you would in a manual. The reason they don't just give a manual gear lever to pick whatever gear is that would be stupid... you can keep both hands on the wheel and shift faster with the paddles.
Saying that you need to flip a paddle once for each gear change only solidifies what I said: You can't skip gears. One flip for each gear change. And you're also not taking into account that only the first flip of the paddle happens instantly, because only one gear can be pre-selected by the transmission. So on any objective measure it would be you who is wrong.
When I want to go from second to fourth in my actual manual transmission, I just go from second to fourth. That is skipping a gear. Shifting from 2nd to 3rd and then 3rd to 4th is not skipping a gear. That is an objective fact. I'm correct... and you continue to struggle to win a debate using emotional nonsense.
Your "automated clutch pedal" comment is remarkably stupid, and not even worthy of debate in any fashion.
#67
DCTs are not manual transmissions. Ever.
manual:
"of or done with the hands."
"a thing operated or done by hand rather than automatically or electronically, in particular."
I know manufacturers have used the term, "automated manual" at times, but frankly the term makes no sense.
manual:
"of or done with the hands."
"a thing operated or done by hand rather than automatically or electronically, in particular."
I know manufacturers have used the term, "automated manual" at times, but frankly the term makes no sense.
#68
E-Ray, 3LZ, ZER, LIFT
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^^^
Suggest you watch the video in Post #50 of the internals of one they take apart. It IS a manual with hydraulic pistons moving the shift forks instead of your hand. It has efficient spur gears, synchro's assuring smooth operation etc.
But I guess if you have no idea why two non sliding surface spur gears with few teeth under load in mesh is much more efficient than sun and multiple planetary gears on shafts activated with oil soaked clutch packs in an automatic- yep they are "just like an automatic trans!"
For smoother operation that unit does use multiple disk clutch packs for the dual clutch arrangement. Some use two dry clutches similar to what is in the C7 M7.
Suggest you watch the video in Post #50 of the internals of one they take apart. It IS a manual with hydraulic pistons moving the shift forks instead of your hand. It has efficient spur gears, synchro's assuring smooth operation etc.
But I guess if you have no idea why two non sliding surface spur gears with few teeth under load in mesh is much more efficient than sun and multiple planetary gears on shafts activated with oil soaked clutch packs in an automatic- yep they are "just like an automatic trans!"
For smoother operation that unit does use multiple disk clutch packs for the dual clutch arrangement. Some use two dry clutches similar to what is in the C7 M7.
Last edited by JerryU; 12-05-2018 at 07:40 PM.
#69
Le Mans Master
Originally Posted by JerryU
^^^
Suggest you watch the video in Post #50 of the internals of one they take apart. It IS a manual with hydraulic pistons moving the shift forks instead of your hand. It has efficient spur gears, synchro's assuring smooth operation etc.
But I guess if you have no idea why two non sliding surface spur gears with few teeth under load in mesh is much more efficient than sun and multiple planetary gears on shafts activated with oil soaked clutch packs in an automatic- yep they are "just like an automatic trans!"
For smoother operation that unit does use multiple disk clutch packs for the dual clutch arrangement. Some use two dry clutches similar to what is in the C7 M7.
Suggest you watch the video in Post #50 of the internals of one they take apart. It IS a manual with hydraulic pistons moving the shift forks instead of your hand. It has efficient spur gears, synchro's assuring smooth operation etc.
But I guess if you have no idea why two non sliding surface spur gears with few teeth under load in mesh is much more efficient than sun and multiple planetary gears on shafts activated with oil soaked clutch packs in an automatic- yep they are "just like an automatic trans!"
For smoother operation that unit does use multiple disk clutch packs for the dual clutch arrangement. Some use two dry clutches similar to what is in the C7 M7.
#71
Race Director
Have you ever driven one? It is surely automated but drives NOTHING like a traditional slush box. Why is it so difficult for certain very obstinate folks on this Forum to comprehend that these dual-clutch trannies are really a hybrid?
Their internals are MUCH different than traditional automatics (like Vettes have been saddled with since 1953). I have seen NOBODY in this thread claim they are not automated. And yet guys like you keep claiming that folks are saying just that. And then doubling down by asserting that these dual-clutch trannies will work and/or feel like any automatic heretofore installed in any Vette. That’s just flat-out wrong — and it is not even close.
Their internals are MUCH different than traditional automatics (like Vettes have been saddled with since 1953). I have seen NOBODY in this thread claim they are not automated. And yet guys like you keep claiming that folks are saying just that. And then doubling down by asserting that these dual-clutch trannies will work and/or feel like any automatic heretofore installed in any Vette. That’s just flat-out wrong — and it is not even close.
#72
Race Director
Just speaking for myself — Neither my wife nor I have owned an automatic vehicle in 38 years. You might say we REALLY dislike them. And yet after driving a DSG we are both open to one. Because, HONESTLY, they feel way better than the typical slushboxes that we so dislike. So it’s simply a matter of how important the clutch pedal is to us. Maybe not so much.
#73
Race Director
Thread Starter
Any way we can stop the semantics of if the DCT is an auto or a manual transmission and get back to how it works? It does not make any difference if you call it an automatic or a standard. Just call it a DCT and be done with it.
Now on back to its inner workings.........
Now on back to its inner workings.........
#74
Le Mans Master
You say that I'm "wrong", but then do not say anything that contradicts what I have said. You simply dig your hole deeper.
Saying that you need to flip a paddle once for each gear change only solidifies what I said: You can't skip gears. One flip for each gear change. And you're also not taking into account that only the first flip of the paddle happens instantly, because only one gear can be pre-selected by the transmission. So on any objective measure it would be you who is wrong.
When I want to go from second to fourth in my actual manual transmission, I just go from second to fourth. That is skipping a gear. Shifting from 2nd to 3rd and then 3rd to 4th is not skipping a gear. That is an objective fact. I'm correct... and you continue to struggle to win a debate using emotional nonsense.
Your "automated clutch pedal" comment is remarkably stupid, and not even worthy of debate in any fashion.
Saying that you need to flip a paddle once for each gear change only solidifies what I said: You can't skip gears. One flip for each gear change. And you're also not taking into account that only the first flip of the paddle happens instantly, because only one gear can be pre-selected by the transmission. So on any objective measure it would be you who is wrong.
When I want to go from second to fourth in my actual manual transmission, I just go from second to fourth. That is skipping a gear. Shifting from 2nd to 3rd and then 3rd to 4th is not skipping a gear. That is an objective fact. I'm correct... and you continue to struggle to win a debate using emotional nonsense.
Your "automated clutch pedal" comment is remarkably stupid, and not even worthy of debate in any fashion.
There is nothing deflective about my comment. I was referring to the manual operation of a DCT, since there are some nut jobs here who keep saying it's an "automated manual", or some derivative. So then all the sudden some contrarian chimes in about DCTs skipping gears without mentioning that it can happen only in automatic mode. So I acknowledged the comment and stated that it proves my point.
There may be other things that a DCT does in automatic mode that I did not mention in my previous comments. But writing detailed posts about such features only serves to bolster my remarks that a DCT is absolutely not a manual transmission. I see people are continuing to spread FUD about this. Probably because they want to believe in their hearts that it is true. It's not. Go back to bed.
There may be other things that a DCT does in automatic mode that I did not mention in my previous comments. But writing detailed posts about such features only serves to bolster my remarks that a DCT is absolutely not a manual transmission. I see people are continuing to spread FUD about this. Probably because they want to believe in their hearts that it is true. It's not. Go back to bed.
I've seen you make these arguments before in the forums, and you're just plain wrong. When you say that flipping paddles on a DCT is the same as "moving a shifter around" I know that you're either just a troll or a dolt, but in either case I have no interest in reading further. You go on justifying your love of automatics by continuing to lie to. I really couldn't care less.
#75
E-Ray, 3LZ, ZER, LIFT
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Location: NE South Carolina
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Perhaps in your mind.
In mine it's not an inefficient "slush box" so it's different. I have had standard shifts in all my DD's for ~60 years! Not super happy the C8 will have a DCT (T for transaxle) but bought the first TRS 80 computer in OH in the mid 1970's (per the Radio Shack Manager who kept reminding me as it was months later than promised) for our R&D Lab and have had a computer every since!
I went from a slip stick, to a TI59 programable calculator to a computer. That TRS80 did not have the power of my iPhone, they got better. I'll give the new technology a chance and get good at using paddles!
In mine it's not an inefficient "slush box" so it's different. I have had standard shifts in all my DD's for ~60 years! Not super happy the C8 will have a DCT (T for transaxle) but bought the first TRS 80 computer in OH in the mid 1970's (per the Radio Shack Manager who kept reminding me as it was months later than promised) for our R&D Lab and have had a computer every since!
I went from a slip stick, to a TI59 programable calculator to a computer. That TRS80 did not have the power of my iPhone, they got better. I'll give the new technology a chance and get good at using paddles!
Last edited by JerryU; 12-06-2018 at 12:41 AM.
#76
Melting Slicks
Speednet, by now, we all know how you think a DCT works and functions (and most of us do not agree with it). Even though your name callings were not addressed to me I find it offensive. If I see another instance of it, I'll insist the Admins give you some timeout here. I, for one, need a break from your tone of voice.
#77
Melting Slicks
Have you ever driven one? It is surely automated but drives NOTHING like a traditional slush box. Why is it so difficult for certain very obstinate folks on this Forum to comprehend that these dual-clutch trannies are really a hybrid?
Their internals are MUCH different than traditional automatics (like Vettes have been saddled with since 1953). I have seen NOBODY in this thread claim they are not automated. And yet guys like you keep claiming that folks are saying just that. And then doubling down by asserting that these dual-clutch trannies will work and/or feel like any automatic heretofore installed in any Vette. That’s just flat-out wrong — and it is not even close.
#78
E-Ray, 3LZ, ZER, LIFT
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DCT is Needed For Efficency
Something to consider as Mary Bara is defending the GM decision to lay off ~15,000 US workers to produce more energy efficient cars! DCT will have an impact on the Corvette of the future! Perhaps near future.
DCT (T for Transaxle) is needed to make it easier to implement Start/Stop that reduces some of the ~15% energy in gasoline wasted, on average, idling. The next step is to use an F1 type Kinetic Energy Recovery System (KERS) to reduce the gasoline engine's large energy consuming use, accelerating from a stop or slow speed to cruising speed. (Suggest Googling Newton's 1 Law of Motion!)
After Start/Stop in normal driving, a light weight KERS system could be used to bring the Vette to cruising speed before starting the engine. Then regenerate that energy while braking. As used in F1 it could also delivery ~150 extra hp for 5 or 6 seconds when driving in anger! (Perhaps of interest to some is only about 15% of the energy in gasoline gets to propel the car. Most of the remainder goes to wasted heat out the exhaust, into the cooling system and friction. And of that 15% that gets to the rear wheels about a 1/3 gets turned back to wasted heat when braking. KERS generates it's stored energy while braking.)
F1 Achievement
F1 has improved their energy efficiency by over 50% overall. They no longer allow refueling and with a 1.6 Liter turbocharged gasoline powered engine are achieving over 800 hp and have the additional ~160 hp KERS that reportedly weighs under 75 lbs. They are beating track records for the same length race on the same tracks as much larger V12 engines on the past.
Flywheel Systems
F1 systems that have been used for the past several years are all using motor/generators coupled directly to the engine and utilizing a ~30 lbs Lithium battery. Some years ago when KERS was first introduced, a few teams used flywheel energy storage. Being mechanically oriented I have been a flywheel energy storage fan since the 1980's! Porsche recently had a 911 Le Mans race car that also produced about 160 hp that stored, delivered and recovered energy on braking using a flywheel that reached 40,000 rpm. It increased the lost rpm when braking. These systems are still being evaluated by various manufactures for passenger car use.
Should IMSA allow a KERS system to be used? Sure if there were no penalty for having an additional ~160 hp, the C8R (and all others) would add one quickly!
DCT (T for Transaxle) is needed to make it easier to implement Start/Stop that reduces some of the ~15% energy in gasoline wasted, on average, idling. The next step is to use an F1 type Kinetic Energy Recovery System (KERS) to reduce the gasoline engine's large energy consuming use, accelerating from a stop or slow speed to cruising speed. (Suggest Googling Newton's 1 Law of Motion!)
After Start/Stop in normal driving, a light weight KERS system could be used to bring the Vette to cruising speed before starting the engine. Then regenerate that energy while braking. As used in F1 it could also delivery ~150 extra hp for 5 or 6 seconds when driving in anger! (Perhaps of interest to some is only about 15% of the energy in gasoline gets to propel the car. Most of the remainder goes to wasted heat out the exhaust, into the cooling system and friction. And of that 15% that gets to the rear wheels about a 1/3 gets turned back to wasted heat when braking. KERS generates it's stored energy while braking.)
F1 Achievement
F1 has improved their energy efficiency by over 50% overall. They no longer allow refueling and with a 1.6 Liter turbocharged gasoline powered engine are achieving over 800 hp and have the additional ~160 hp KERS that reportedly weighs under 75 lbs. They are beating track records for the same length race on the same tracks as much larger V12 engines on the past.
Flywheel Systems
F1 systems that have been used for the past several years are all using motor/generators coupled directly to the engine and utilizing a ~30 lbs Lithium battery. Some years ago when KERS was first introduced, a few teams used flywheel energy storage. Being mechanically oriented I have been a flywheel energy storage fan since the 1980's! Porsche recently had a 911 Le Mans race car that also produced about 160 hp that stored, delivered and recovered energy on braking using a flywheel that reached 40,000 rpm. It increased the lost rpm when braking. These systems are still being evaluated by various manufactures for passenger car use.
Should IMSA allow a KERS system to be used? Sure if there were no penalty for having an additional ~160 hp, the C8R (and all others) would add one quickly!
Last edited by JerryU; 12-06-2018 at 09:05 AM.
#79
Melting Slicks
Nobody here is saying that a DCT has the same driving experience as a torque converter automatic. But the fact that they have invented a better-shifting automatic is not the point. The point was that DCTs are not manual transmissions. For some oddball reason some people here keep wanting to insist that a DCT is an "automated manual" or other such nonsense. Really, think about how dumb that description is.
It is far better to call the PDK transmission a manual transmission with ‘automated features’, than a true ‘Automatic’. I’m not sure why you keep contesting this.
BTW: I have a DCT in my AMG GT R. I can be in say 5th gear and high speed; brake hard for a corner and by pulling and holding the left hand (downshift) paddle, the transmission will almost instantly change down to the lowest acceptable gear. These transmissions are able to change gears in as little as 80 milliseconds when in ‘Race/Sport +’ mode, so for all intents and purposes they are capable of instant gear changes. Certainly they the DCT in my car will change down from 5th to say 2nd far, far quicker than you could ever shift a manual from 5 down to 2, and it does so incredibly smoothly without upsetting the balance of the car. If you do not understand the above you have never driven in a car with a good DCT.
Bish
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Rapid Fred (12-06-2018)
#80
Race Director
Nobody here is saying that a DCT has the same driving experience as a torque converter automatic. But the fact that they have invented a better-shifting automatic is not the point. The point was that DCTs are not manual transmissions. For some oddball reason some people here keep wanting to insist that a DCT is an "automated manual" or other such nonsense. Really, think about how dumb that description is.
Last edited by Rapid Fred; 12-06-2018 at 10:53 AM.