vetteLT193

I have a DCT and it light years ahead of the TC tranny in performance scenarios. However it sucks as a daily driver transmission. SUCKS. It really needs to warm up to behave properly, is terrible in slow driving situations (i.e. parking lots). Behaves differently on hills than a regular auto would. etc. Everyone who says they don't have these issues is just lying or never drive their cars in normal driving scenarios (i.e. the Lambo drivers). Those of us who do both really don't want the compromise. I want a DCT that my wife can stick in auto mode and be comfortable with.

The fix is the new DCT's with a TC. The way they work is the clutches are fully engaged or the TC is fully locked... this way normal driving is not changed from a normal auto if that is what mode you are in. Slow driving is back to normal and not clunky. The tranny can warm up without jerking the car around.

To say a DCT with a TC isn't a DCT is nonsense. The TC is used when it is beneficial to use one. The rest of the time, and the times a DCT shines, the TC is locked and out of the equation.

Shaka

Only one way to go. Lexus LFA type sequential.

NoOne

I've driven the same and was very surprised. Only had about 30 minutes in the car so not sure if it was as smart but it was a great trans without the DCT cost from what I saw.

My understanding is it is there regular trans but with a multi-clutch pack in place of the TC.

The DCT is my S4 was smooth as glass. Other VW/Audi/Porsche DCT's I've driven also were.

2014 seemed to be the big year it changed. 2013 S models had creep and rough start issues but after that MY they have been perfect.

ByByBMW

I have heard this before from DCT owners and all I can tell you is that I am sorry.
My 2013 Boxster S has NONE of the symptoms that you described during slow/parking lot scenarios nor does it need to warm up before behaving. Might I ask what car you are driving with the DCT that is giving you those issues?
As to the statement you made that I highlighted, WRONG! I have no reason to lie about this. My PDK equiped Boxster is well behaved in all the scenarios I have driven it including autocross and a full day event at Inde Motorsports in Wilcox AZ. In both cases the PDK made me a better driver, not good mind you just better than I would have with a manual.
So again, what car are you driving with such a lousy DCT? I want to make sure I don't buy one of them.

vetteLT193

BMW M3.

Doesn't matter if you search on rennlist or any other site with cars that have dual clutch transmissions.... they ALL have reports of clunky, jerky, cold temperature sluggishness, hesitation, or other issues. Typically what I have experienced is the people that have gone from a Manual tranny to a DCT think it's fine. Those that came from an Auto and were expecting something automatic like think it stinks.

It's the nature of the beast. The car can't possibly know what is going on as well as a human would to work the clutch and can't make up for decades of people getting used to the way a TC makes driving feel in an auto. There is a reason why auto manufacturers have pulled WAY back on DCT's in regular passenger vehicles. Someone's expectations on how a Porsche, Lambo, etc drives is likely a lot different than someone expecting a smooth experience from a 'regular' car. And this is what it comes down to... expectations. Decent read here: http://www.autonews.com/article/2015...e-favor-in-u.s.

ByByBMW

You know what I see when I go to reenlist or any other forums I frequent that talk about DCT's? How amazed folks are about how well the cars drive that have them. Are there articles about issues? Sure, just like there are issues with the GM A8 and A6 trannies. Does that make the GM trannies bad? To use your logic the A6 and A8 GM trannies are rubbish and I shouldn't by a Corvette with either of them.
As to the car not being as able as a human to work the clutch and select the gear. Sigh, you haven't driven the PDK then if you say that.
Are they for everybody, maybe not, but if GM were to put a DCT in the ME as good as the Porsche PDK, I would be in line to buy it. The PDK is THAT good.
I don't base my decisions on reading articles. While they are informative and may guide me in a certain direction, they don't make my decisions.
As to your M3, you may have noticed my user name. The M3 DCT's when they came out were terrible I agree. I drove one and hated it. That, among other things, drove me away from a brand I loved.
And in that post, there are references to issues with DCT chief among them Ford, ss well as others. While I can see where folks want the "smooth" shifts they have become accustomed to, that doesn't mean the DCT isn't good. As I have stated mine is great. My wife can drive the Boxster just like any of the other auto cars (non DCT) and has no issues and trust me, she is picky about certain things like clunky transmissions.
Go drive a modern Porsche with the PDK then come back and tell me how awful they are. Until then, no matter how may articles you post, your postings about DCT aren't viable, to me.
But thank your for taking the time to find that article.

NoOne

As I said in my post.

Pre-2013 Audi DCT's have complaints, mostly with creep and jerky launch.

2014+ Zero complaints. If the previous poster says his 2013 Boxster has no issues my guess is Porsche addressed the issues and it filtered down to the other brands.

Even cheap DCT's from VW have been perfect. We are on a Audi/VW corporate lease plan so I've driven, and had, several DCT cars. S4, S3, GTI's, none of them have been anything less than flawless.

Cold weather, sure maybe 1 jerk on the first shift but the 8 speeds in the other Audi's we've had have done the same thing.

ByByBMW

Heck, the TC auto tranny in my Audi A6 has a jerk when slowing down to a stop. TC trannies aren't perfect either it would seem. ��

NoOne

The 8 speed in my wife's SQ5 was a pile of ****, huge problems with the same issue. As you slowed every downshift the car jerked.

elegant

In response to the OP’s thread question, yes the ME will have a DCT.

roadbike56

And this is based on?????

elegant

Being told that by two folks way more highly GM connected than me. Does that guarantee anything? No. However, all the information they told me years about the C7, long before it was revealed, turned out to be totally correct.

As that famous saying goes, “time will tell.” Hopefully we can find definitive information before its reveal.

f-16pilotTX

why did I just smile
that would be outstanding! Would love a DCT!

JerriVette

I wish the c8 would offer a dct. Still the concern of early production of insane amounts of torque that GM powerplants put out snap the current batch of existing dcts. I don't believe GM has tested a dct in the marketplace today that could hold up to the low end torque that GMs powertrain creates.

Wish I was wrong.

I want a dct in the c8.

NY09C6

Our Audi had the same drivability annoyances. Nothing major, but it always amazed me how that characteristic would be tolerated in a luxury car when it wouldn’t be in a Chevy Malibu.

NoOne

What sucked was we had a Q5 2.0 loaner that was absolutely perfect.

I should have left when the tech told me DCT's were rough shifting, he didn't realize it did not have a DCT.

RedLS6

A TC planetary is in the next gear already. All that needs to be done to engage it is to release one clutch while simultaneously engaging another corresponding to the next gear path. No extra gears or components need to move or align.

A planetary is actually in more than two gears at once, or more specifically, it has multiple gear paths available with only two clutch movements. This is why a transmission like the A8 can skip multiple gears on the downshift, with a single clutch release / another single clutch engagement, unlike many DCTs.

I think what we all want is a more responsive shift from paddle to engagement, while maintaining smooth fast starts and smooth operation. For a TC planetary, this comes down more to the actuation and various delays, than it does the actual gear or tc design. If GM can accomplish this with a brand new DCT or with a faster more responsive TC planetary, then I'm OK with either.

JerriVette

I wouldn't be surprised if an advancement of GM s planetary gearbox could be utilized.

Thank you for your insights.

JoesC5

I believe that I read that the 750 HP ZR1 has 715 lb-ft of torque. I also believe that the TR-6070 manual transmission in the ZR1 with 715 lb-ft of torque is the same as used in the Z06 with 650 lb-ft of torque. The Tremec TR6070 is not rated for 715 lb-ft of torque, so there must be a bunch of torque management going on with the 7M ZR1.

If GM does go with a smaller twin turbo V8 in the mid engine Corvette, I doubt it will have the stump pulling 715 lb-ft of torque found in the 6.2L LT5.

Some examples of smaller engines with a DCT.

AMG GT R with a 4.0L TT V8 at 577 HP and 516 lb-ft of torque.
Porsche GT2 RS with a 3.8 L TT flat six with 700 HP and 553 lb-ft of torque.
Ford GT with a 3.5L TT V6 with 647 HP and 550 lb-ft of torque.

The Tremec DCT TR-9007 is rated at 664 lb-ft of torque, so I'm assuming it could be used behind a 750 HP LT5, without breaking since the TR-6070 can, in a mid engine car and surely the TR-9007 DCT can be used behind either a 4.2L or a 5.5L V8 with much less than 715 lb-ft of torque in a mid engine Corvette.

Do you believe that a 5.5L TT V8 in the mid engine Corvette will have more than 664 lb-ft of torque?

Lets assume that you could reduce a 6.2L LT5 to 5.5L and not change a thing other than it's displacement and the supercharger's size(11% smaller). That's ~11% reduction. Reduce the 715 lb-ft of torque by 11% and you have 636 lb-ft of torque. That's well within the TR-9007's capability. With twin turbo's instead of a Root's Blower, I believe the engine torque would even be slightly lower.

JerriVette

I don't believe GM will go with a Dohc engine in the 8 th generation.

Jmo

I don't believe GM will go with a dct with the mid engine ohv corvette.

I wish GM would but I don't believe GM will.

I imagine we will find out in time