~Stingray

I thought the auto c7 had paddle shifters. Doesn't that mean a Dual Clutch Transmission?

Shaka

No it doesn't. Google dual transmission to check out animated videos. Not to be confused with dual or triple clutch plate that you can install on your Vette in place of one. Autos are electronically controlled so it is easy to have human intervention via paddles. There are many other clutches within the auto transmission.
There have been electronically controlled manual transmissions, like a Ferrari 430 and 360 with paddle shifts.
There have been push button electro magnetically controlled autos like Chrysler had in the 50s.
There have been electro mechanical shifters on manual transmission which made them autos. Renault had them in the 60s. Motor cycles have multi disc clutches on their sequential gearboxes. DCTs have multiple clutches in each clutch pack which also have their own input shaft.Google is your friend.

musclecar6

Paddle shifters are just a way to shift the transmission manually. The transmission may be automatic with a torque converter or dual clutch, single clutch etc. Many cars today have auto's with paddle shifters and a lesser amount ( BMW, Porsche, etc for some of their cars) have dual clutch trannys with paddle shifters.

Achmed

Do you foresee the acceleration times being better in a hypothetical 2015 8-speed auto versus a 2014 6-speed auto? If not or if only very marginally, I'm still not sure why the preference of an A8 over an A6 is as strong as it is.

b4i4getit

I am sure GM will change the gear ratios in a new transmission design to give optimum performance and fuel economy as well as lighter weight. I don't think the internal components have changed in the 6L80 since it was introduced.

Achmed

So perhaps 0-60 in 3.8 and 1/4 mile in 12.0 (for the A6 C7) will improve to something like 0-60 in 3.7 and 1/4 mile in 11.8 (for the A8 C7)? What is the actual estimated improvement in acceleration times?

p.s. the reason I'm asking so many specific questions is because I'm interested in an auto and will have to decide between waiting for the 8 speed or not

Mike Campbell

Hey guys have you ever wondered why Chrysler has been spouting an 8 speed tranny for years now,but has NOT put one in their Hemi SRT's??? Because...they cannot handle the torque!! So why should GM put one in a Corvette? So all of you can complain about it not working? NOT... Let's wait until they have one that won't blow apart. Meanwhile...I'll just keep booking along in my obsolete incapable A6.

Thespian

Doesn't the 2014 Jeep Grand Cherokee SRT with the HEMI V8 have an 8-speed?

Mike Campbell

Maybe they just added it for 2014....but they ( Chrysler)talked about it for 6 years. I know all the other SRT owners that I know with 2006 to 2013's all have a 5 speed auto's in them. Plus a couple blew the 5 speed up along the way. But, they're still rockets!

JudgeNjury

Yes the new SRT jeep does have the 8 speed..

oicw

You may want to do some research before making a statement like that. The ZF 8 spd has been used in vehicles with FAR more torque than the 6.4 HEMI.

And as others have pointed out, the Jeep SRT uses it.

A more correct statement would be that production hasn't caught up for the high torque spec 8 speed. Therefore, they put it in vehicles that affect CAFE the most - Grand Cherokee, Durango, Ram, and volume sellers (V6 sedans).

b4i4getit

Well here is how I look at it. If you absolutely have to have a C7 right now then get the A6. If however you can afford to wait and have no need to be an early adopter consider the following.

- first year teething problems
- limited availability
- some dealers adding markup
- engineering changes in 2015

I am waiting for the Z06 and a better transmision being either a DCT or A8. If it arrives great if not I will look elsewhere. In my opinion the A6 is long in the tooth and obsolete. All the comments about the C7 not needing something better because of torque are just to convince others to buy it.

Achmed

Personally I don't care if the C7 transmission is 6 years old or whatever, as long as the next transmission won't yield any material improvement in acceleration. What is the metric used to decide whether the A6 is obsolete or not? I don't think the metric should simply be how long it's been used for or whether it's less speeds than some of the other modern automatics.

b4i4getit

Consider that the C7 is heavier than the outgoing C6. I think its almost a given that the new transmission whatever it is called will carry with it significant weight savings. This translates into better fuel economy as well as increased performance. They would not go to all the trouble to bring out a new transmission if there were no benefits that they could advertise and have people want.

musclecar6

Yes. So much for that concern.

Achmed

Fuel economy sure, but so far I'm not convinced that it'll necessarily accelerate better. You mentioned lighter weight of the new transmission - are 8 speeds generally lighter? Or is the new 7-speed manual for example lighter than the C6 manual?

Shaka

ZFs A8 or a GM equivalent in a C7, will be very nice. I like the Lexus LFA gearbox if I had my way. An auto or a sequential gearbox is the only solution. Forget a DCT folks, except for kiddy cars in the future.

Jamaha will use their seamless gearbox for the first time the Moto GP on Sunday. Honda has had it for a couple years which comes from F1. The only true seamless gearboxes in the world are F1

moto gp rossi

F1 gearbox with an animation.

Here is a MTI conversion wich is pretty cool but much heavier than a true sequential.
mti c6 conversion.

Then there is the DCT.
zf 7dt

The F1 gearboxes are truly seamless in that they engage the next gear before the current gear is released. Used in up or down shifts.

The video above is not technically correct. F1 gearboxes have 2 barrels which are used to engage the gears. When a shift is requested the first barrel is asked to disengage the current gear, however due to the load on the gearbox the gear cannot disengage. About 1ms later the 2nd barrel selects the target gear, as the target gear is engaged, the gearbox is momentarily in 2 gears. As the target gear is engaged, the output shaft speed drops, this removes the load off the current gear and allows it to release. At no point during the shift has a gear not been selected.
It doesnt have to be this complicated in a Vette especially if they use their new torque converter but the girls will still bitch about the lack of dual clutches.

I can see F1 type buttons and dials on the steering wheel to change shift mode settings for street, track, rain etc. Like the ZF A8 and the sequential gearbox, they will be cheaper, stronger and more compact than what is currently available.

~Stingray

I think I may have misrepresented myself. I wasn't trying to say that the paddle shifter is a DCT. However, I was thinking one must proceed the other. Let me explain what I thought. I thought that DCT meant that a car has two clutch systems, one for manual intervention and the other was an automatic. That said, you can't have an actual stick with an automatic so the paddle shifters are used to electronically change the gears when a human says too (or the autos with the + and - next to the mode shifter (Drive, reverse, neutral) -- never knew what to call it in an auto). The only difference is that the actual clutch in a DCT is computer controlled. So the engine will stay in first, revving until the red line, until the driver flicks the paddle to tell the car to go to second. With that in mindset, I thought the C7 had a DCT. Am I am completely wrong about this?

Shaka

Above is a video of a DCT. You probably could Google a more simplified animation. I have explained the workings of the various transmissions on this thread.

~Stingray

Finally watched the videos. I guess I did have it completely wrong. Thanks for the info.
Just to clarify, what transmission does the new c7 have?