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-   -   Is a dual-clutch transmission right for you? (https://www.corvetteforum.com/forums/c8-general-discussion/4294267-is-a-dual-clutch-transmission-right-for-you.html)

68roadster 07-10-2019 12:44 PM

Is a dual-clutch transmission right for you?
 
Not about a high performance car, but some good info.


ByByBMW 07-10-2019 01:12 PM

I can only speak to the negatives and I am only comparing the video to my personally owned DCT which is the Porsche PDK.
1. The hesitation when shifting to an unexpected gear is NOT an issue in the PDK
2. Lots of folks talk about the slow speed creeping. While it seems to have happened to other DCT's, the PDK doesn't seem to have the issue and has auto hill control built in and creeping in the PDK is seamless. I have driven the PDK in stop and go traffic in LA on the 405. You won't find worse creeping issues than are found there. There are no reports of Porsche PDK's having this issue that I am aware of.
3. The steep hill item is also a non issue in the PDK.

Just one DCT users personal opinion. And note, I have no way of knowing anything about the DCT coming in the C8 so until the C8 is released and tested, BUYER BEWARE!

dexterkatt 07-10-2019 01:20 PM

I have had no manufacture's issues with my 2010 Nissan GTR. That being said, I have spent considerable amount of money for a upgraded DCT after engine mods. 688 rwhp.

RapidC84B 07-10-2019 02:12 PM

The only DCT I've ever driven is a PDK. Put it in auto mode and it drives like any other auto. Put it in sport mode and it's very quick and holds gears longer. Put it in manual mode and it shifts instantly. It's not as engaging as a manual on a Sunday cruise, but it's fun and very versatile.

vndkshn 07-10-2019 02:24 PM

IF (and knowing GM... that's a HUGE "IF") it shifts and acts like PDK, I may be talked into one. I am impressed with PDK, at least the later versions (not sure if the early experiences were later fixed in those cars with software or not). I'm not convinced it will keep me as engaged and entertained, but it's about as close as I can imagine.

JDSKY 07-10-2019 02:26 PM

Why yes, yes it is...... Just FYI, the DCT in my wife's Hyundai daily driver has been flawless even though the masses that own them complain constantly because they don't bother to read the owners manual.

Foosh 07-10-2019 02:34 PM

PDK is the gold standard, and I agree it exhibits zero objectionable traits, without having to read the owner's manual or do anything a certain way. However, like modern TCs such as the ZF8, there is a lot of tuning involved, and Porsche spent years perfecting the PDK in conjunction with manufacturer ZF. Just as all ZF8 TC autos do not perform the same because of programming, I would expect the same w/ a new DCT.

I think it is a very real concern as to whether it's as "perfect" as the PDK out of the box.

RapidC84B 07-10-2019 02:43 PM


Originally Posted by Foosh (Post 1599731439)
PDK is the gold standard, and I agree it exhibits zero objectionable traits, without having to read the owner's manual or do anything a certain way. However, like modern TCs such as the ZF8, there is a lot of tuning involved, and Porsche spent years perfecting the PDK w manufacturer ZF. Just as all ZF8 TC autos do not perform the same because of programming, I would expect the same w/ a new DCT.

I think it is a very real concern as to whether it's as "perfect" as the PDK out of the box.

Of interest, the mules had a flap labeled "TCM PORT" on the passenger side quarter about where the fuel door is on the driver side. Most likely for quick easy access to upload tunes to the Transmission Control Module. Hope that means they spent a lot of time tweaking/testing/refining it.

ByByBMW 07-10-2019 03:03 PM


Originally Posted by Tool Hoarder (Post 1599731501)
Of interest, the mules had a flap labeled "TCM PORT" on the passenger side quarter about where the fuel door is on the driver side. Most likely for quick easy access to upload tunes to the Transmission Control Module. Hope that means they spent a lot of time tweaking/testing/refining it.

Fingers crossed.

vndkshn 07-10-2019 03:11 PM


Originally Posted by Tool Hoarder (Post 1599731501)
Of interest, the mules had a flap labeled "TCM PORT" on the passenger side quarter about where the fuel door is on the driver side. Most likely for quick easy access to upload tunes to the Transmission Control Module. Hope that means they spent a lot of time tweaking/testing/refining it.

But... a relatively small number of testers (both cars and drivers) does not offset the thousands of cars with at least that number of drivers that Porsche has been able to take advantage of. When PDK first released, it was not perfect, or really even close. Had a couple of students who ran into issues, a good friend of mine got rid of his car over problems with PDK. Now, I think that their issues were all software related because I've talked to owners of that same generation who say it got better and better each time it went in the shop... but that still took time.

RapidC84B 07-10-2019 03:13 PM


Originally Posted by vndkshn (Post 1599731659)
But... a relatively small number of testers (both cars and drivers) does not offset the thousands of cars with at least that number of drivers that Porsche has been able to take advantage of. When PDK first released, it was not perfect, or really even close. Had a couple of students who ran into issues, a good friend of mine got rid of his car over problems with PDK. Now, I think that their issues were all software related because I've talked to owners of that same generation who say it got better and better each time it went in the shop... but that still took time.

Well... hopefully Tremec poached a ZF engineer or two.

Foosh 07-10-2019 03:17 PM


Originally Posted by vndkshn (Post 1599731659)
But... a relatively small number of testers (both cars and drivers) does not offset the thousands of cars with at least that number of drivers that Porsche has been able to take advantage of. When PDK first released, it was not perfect, or really even close. Had a couple of students who ran into issues, a good friend of mine got rid of his car over problems with PDK. Now, I think that their issues were all software related because I've talked to owners of that same generation who say it got better and better each time it went in the shop... but that still took time.

^ Bingo and exactly why I brought it up. I remember those days well. A whole bunch of 911 owners were not happy, and I recall it being much like the A8 C7 situation.

On the heels of that, I'm holding my breath here, because it could get ugly if there's a repeat of that.

Corgidog1 07-10-2019 03:25 PM

A dual clutch transmission is not for me. I like the single clutch model with a pedal you step on to disengage.

ByByBMW 07-10-2019 03:25 PM


Originally Posted by Foosh (Post 1599731684)
^ Bingo and exactly why I brought it up. I remember those days well. A whole bunch of 911 owners were not happy, and I recall it being much like the A8 C7 situation.

On the heels of that, I'm holding my breath here, because it could get ugly if there's a repeat of that.

:iagree: And it is the #1 reason I will not buy a first year C8.

Warp Factor 07-10-2019 03:41 PM

I don't think there would be anything better about a DCT than a good torque-converter paddle-shiftable transmission.
The DCT in my Audi is pretty much indistinguishable from a conventional automatic. When I first got the car, I had to look it up to figure out which it had.

Foosh 07-10-2019 04:01 PM

I agree. The ZF8 in my F-Type was tuned in such a way that it was every bit as good as the PDK. I was storing a friend's 911 at the same time I owned the F-Type, and he asked me to keep it exercised.

And interestingly enough, we have two other cars with ZF8s. Each of them is tuned a bit differently, both from each other, and from the F-Type. The same box felt like 3 different transmissions.

vndkshn 07-10-2019 04:10 PM

Moral of the story: It took Porsche and ZF a few years to get it right (I don't know what trans Audi is using for DCT or who makes it, searching kinda makes it seem like it is VW), I expect the same from Chevy and Tremac. The problem, how much harm is done before that time arrives?

I found this article interesting:
https://www.caranddriver.com/news/a2...transmissions/

The part I laughed at was when he said DCTs are heavier, which is ironic because many of the same proponents of the technology coming to the Corvette are the same who want it to stay standard OHV because it is lighter that way!

AORoads 07-10-2019 04:23 PM

What I'd like to know (and what I might be concerned about) is the expired-warranty cost to replace parts of a DCT. I don't see much mention of that, possibly because most people who own them either don't keep it past a warranty, or keep the car but use it very little. I used to know the costs to rebuild, maintain and even purchase a new 4A, 5A, and 6A, but I've left that info untouched for too many years to be current.

Anyone got any ideas on costs AFTER the warranty is off the car and DCT trans? If you want, you can take labor rates if it's a full installation, at between $100-$150/hr.

Maxpowers 07-10-2019 04:31 PM


Originally Posted by Foosh (Post 1599731920)
I agree. The ZF8 in my F-Type was tuned in such a way that it was every bit as good as the PDK. I was storing a friend's 911 at the same time I owned the F-Type, and he asked me to keep it exercised.

And interestingly enough, we have two other cars with ZF8s. Each of them is tuned a bit differently, both from each other, and from the F-Type. The same box felt like 3 different transmissions.

Was your ZF8 as quick as a PDK when shifting in manual mode? Curious because I drove an Aston Martin Vantage V12 last year (which was an auto). This shifts were very good, but in manual mode they weren't PDK quality.

68roadster 07-10-2019 04:35 PM

Would a bad /worn out clutch in the GM DCT be covered or considered a wear item not covered?


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