Tadge specifically addresses DCT in the C7
 

Go to 54:09 - http://www.corvetteblogger.com/2013/...-the-ncm-bash/

1. There aren't any that will fit in the platform.
2. There aren't any that will handle the torque output of the LT1.
3. They don't handle AFM in V4 mode.

Watching this video and the other bash seminar videos it's quite clear they put serious work into this car. They've reviewed and improved every single area of the car. They've used the latest technology to give you a car that has an incredibly wide range of capability. You can have a truly track-capable car that becomes a daily driver with the turn of a knob; no compromises.

:thumbs:

Well he is 100% incorrect about none that will handle the torque of the LT1...

not sure about the other two points, but I call ********. They could of done it, it just would of been expensive, oh well, perhaps at the refresh.

What other car makes 450+ ft/lbs for such a broad rpm range? Most vehicles equipped with DCT make horsepower via rpm and relatively low torque.

I watched the vid, what he's saying is that there is not a DCT that will fit AND handle the torque.

For purposes of this discussion, the Veyron has a DCT and makes 1000 lb-ft. It is obviously modified to handle that much torque and I am not suggesting that the development cost associated with the Veyron apply to the Corvette, but the point is that DCTs can be made to handle more torque than the Corvette will ever need.

The issue is not the torque. Saying it won't fit is a better reason. If they did not develop the C7 with the intention of using a DCT, they can't just drop one in after the fact because they are bigger and heavier so the current packaging may not allow for it.

No DCT is fine as long as the Corvette has a comparable offering. GM really has no choice but to put their new 8 speed in the Vette when it's ready but it will never shift as fast as a DCT. We can only hope it's close.

2014 GT-R - 463 lb-ft
SLS AMG - 479 lb-ft
BMW M5 - 500 lb-ft (from 1500 rpm)
Ferrari F12 - 509 lb-ft
Porsche 997 Turbo S - 516 lb-ft (from 2100 rpm)
Panamera Turbo S - 553 lb-ft (590 with overboost)
LaFerrari - 663 lb-ft
McLaren P1 - 664 lb-ft

Various Audis have both dual clutch and cylinder deactivation.

Of course it's not going to fit if you don't design it to fit from the start. And of course it's not going to fit from the start if you have no viable DCT plan to begin with.

That makes sense... sounds like they chose AFM for the economy gains from the start and designed around that requirement.

A friend of mine is a big Audi fan, he test drove the new S7 with DCT and AFM, He said he could distinctly feel when going in and out of 4cyl mode and while in 4cyl mode. He was so disappointed with DCT-AFM that he bought a BMW.

That might answer a lot of people's questions.

Maybe its not an issue of getting it to work, it's an issue of it getting to work perfectly like they would want. I'm sure the Vette will eventually get one in a performance model, but they have to have the right setup that will handle all the power, fit, and work nicely.

I imagine the Zxx car(s) will get one eventually, as they may not have AFM on those cars anyway.

"At the same time, the 2013 Audi S6 is also unexpectedly refined. The use of air suspension takes away much of the road harshness that is the customary price you pay for low-profile tires, while the engine's cylinder-deactivation system works so silently and transparently that you're pleasantly surprised when you discover the good news about the fuel economy."
--edmunds.com on S6

"The engine has a cylinder cutoff feature that powers it down to a four-banger at relaxed cruising speeds. The shutoff is hard to detect, and neither my driving partner nor I could find the indicator light on the multi-function dash."
--Motor Trend on S6/S7

"Stop/start worked consistently well through our test, but it was harder – all credit to Audi – to detect the cylinder deactivation at work. This is partly because this car is so quite and refined at low revs that you can’t really hear the engine anyway, and when you put your foot down, you’re immediately calling for all eight cylinders."
--Car Magazine on S6

"like the rest of the car the S7 is just too subtle to make a song and dance about its moves. Even the active cylinder deactivation, switching to four cylinders at low revs and throttle loads, is barely perceptible - partly thanks to the active noise cancellation that aims to reduce any change in engine speed frequencies."
--Carenthusiast.com

"When they're not driving it fast, the other S6 detail people will focus on is its cylinder deactivation. Can you really tell when it's running on four, not eight? Well, if our first drive is indicative, no. There's a light on the dash to say when four cylinders are turned off: without this, we wouldn't know."
--MSN Autos UK

"its operation is seamless, which will be a shock to those of you who understand primary balance.
Audi engineers have gone to incredible lengths to ensure you can’t pick when the system is operating. Active Noise Control (ANC) and dynamic engine mounts play a huge role in the technical subterfuge. Four microphones integrated into the headlining record the complete noise spectrum within the cabin, isolating and discarding music and conversation. When the cylinder deactivation shuts down half of the engine, a sensor at the crankshaft tells the microphones to generate a 3D ultrasonic pattern to disguise any vibrations from the unbalanced engine. The speakers work whether the audio system is on or off. It is a brilliant solution and there’s no way to tell when then engine is in V4 or V8 mode. You have to cheat and refer to the instrument display."
--Teamspeed

Other tests by Automobile Magazine, Car and Driver, TopGear, Autoexpress, etc, don't even mention it. Many of them suggest the car is too refined, so if indeed it was intrusive, it should have been noted as a black mark. I suspect anyone who is a self-proclaimed "fan" that is so turned off by the AFM operation is probably looking for nits to pick...with a microscope.

Tadge said none can handle the torque AND fit the platform. The OP mistated how the information was stated or tadge just stated it that way in that particular speech. I spoke with him directly about it and while there are boxes that fit, they cant handle the torque.

To those posting tq numbers, having blown various tranny's apart with LSX motors, I can tell you that the tq number doesnt really tell the story, its the torque curve and tq onset, as well as the responsiveness of the engine. The tq that these motors make at such low rpm is what breaks sh*t...the LT1 curve is even worse. You gotta have bulletproof sh*t to handle that, and not kill a company with warranty claims.

He has owned several Audis, his disappointment was visible, traded his S5 for a M5. I didn't say he was self proclaimed, that was my view of him, no need to make things up. Those magazines never mentioned the many catastrophic Porsche M96 engine failures either, or weren't they real?

This hits the proverbial nail on the head. All manufacturers made similar claims as GM when they didn't have DCT. When GM will be done building, and I guarantee they are working on one, then it will be the new fantastic DCT. Until then it will be it can't be done, or it's too heavy, or it doesn't fit.

GM will finish theirs after everyone develops one. That's just the truth, it's cheaper to walk on a beaten path and GM wants the bargain vehicle. The GM costumer wants the bargain vehicle, so he/she will have to wait.

I love it when people compare cars costing 2 - 6 times the price of the vette in question.....:lol:

Did you ...want to reinforce the stereotype?? lol

No, if I wanted to do that I would have mentioned LaFerrari is probably at least 15 times the cost :lol:.....:cheers:

I call BS on all three items above. The first two are backed up by a post I made about the Corvette being raced at the 12 hours of Sebring. Speed did a spot on the DCT transmission that the GM Corvette team was running. Had 14ms shift times. It also handled all the torque of the racing motor. And it obviously fit in the C6R, which is based on the C6 and the C7 is not any different architecturally. As for the third item, that is BS too. A DCT is not any different than a regular manual tranny other than the clutches and pushbutton shifting. So I can't think of any reason why AFM would be a problem other than vibration and feeling the engagement/disengagement, which would also be a problem with a regular manual transmission and that is obviously not the case. They are just deflecting and making excuses until the DCT that they are developing is ready. Probably for the ZO6/ZR1 models that will come for 2015.

^This,this,this^

Man, I didn't realize we had such a high number of engineers on this site.

:iagree:
The one thing I would point out is that the SMG in the C6R is a purpose built race unit. I looked at one in Carlisle a few years back (I think Katech was offering one for the C5/6 if I remember correctly) and it retailed for around $27,000. Perhaps it was just a bean counter decision. I doubt we would have a base model that costs under $52k if they had gone that route. The cost would obviously be distributed over more units, but it would still be an increase.
Besides, just like with any model, you can't show all your cards the first year...