Old buckeye

I apologize if this has been discussed but it appears GM has made an improvement to their auto transmission.

For the C7, I have read that the auto may be just a wink faster than the manual. Is this true? Did the change in the torque converter cause this and if so what did they do to the torque converter design to make the auto a “wink” quicker?

When you see the times for Zero to 60 mph quoted by GM for a C6 awhile back, the auto was .3 to .4 seconds slower which I realize is not that much.

6-spd manual w Z51 4.1 sec
6-spd manual w/o Z51 4.3 sec
4-spd auto tranny w Z51 4.5 sec
4-spd auto tranny w/o Z51 4.6 sec

Obviously manual depends on the ability of the driver and I cannot verify if the data above is factual but this is what I found doing a search on this web-site.

b4i4getit

In theory the automatic should be quicker than a manual but nobody really knows since I don't believe official numbers have been released.
Eventually we will know but I don't think it will be a big difference.

Shaka

Tadge says C7 Z51 owners will be very pleased with the auto in the C7. It will be tuned differently to the stock c7.
I don't know what mods they will do for high G turns. Perhaps there will be some sort of a dry sump that combines the xmission oil and the diff clutch oil. The torque converter is very efficient these days but still compromised toward economy and everyday driving with much lower stall speeds. Tadge said the shifts will be faster and clutches will be pre loaded. Quick fill and drainage of the clutch drums will do that.
Automatic transmissions are in their infancy. DCTs days are numbered in high performance cars.
Rumor has it from pretty good sources, like Jalopnic and others, that a pretty fancy 8sp. auto is in the works for 2015 C7, which is been designed in conjunction ZF USA. It will go into the high HP Vette as well as the stock one. I doubt whether they will go for a wet clutch pack like the MB E and SL 63/5 has done. The current TC has an internal clutch pack and ZF has an advanced combined design.
Asian has similar designs in Lexus cars. These transmissions are much lighter than the 7sp manual and 6sp auto and certainly the bucket of bolts DCT.
I would like to see the LFA F1 type design in a Vette myself.

JoesC5

4-spd auto was only used in the 2005 C6. Since 2006, the 6-spd auto was used, so you can't compare a 2014 C7 with a 6-spd auto to a 2005 C6 with a 4-speed auto.

Old buckeye

Thanks - I did not catch that those times were with a 4 speed. But this is another link on the 2008 and it indicates:

"For the 2008 model, the Corvette receives a new engine, the LS3. With displacement increased to 6.2 liters (376 cu in; 6162 cc)[3] , power is increased to 430 hp (321 kW) and 424 lb·ft (575 N·m) of torque, or 436 hp (325 kW) and 428 lb·ft (580 N·m) with the optional vacuum actuated valve exhaust.[4] The previous Transmission Technologies Corporation T56 transmission on manual Corvettes was replaced with a new version, the TR6060, in model year 2008.[5] Manual Corvettes have improved shift linkage; the automatic model is set up for quicker shifts, and (according to Chevrolet) goes from 0 to 60 mph in 4.3 seconds, faster than any other production automatic Corvette.

Old buckeye

Thanks for that information. 8 speed auto - interesting!

User 2623

They certainly changed the shifting points based on a software fix with the GS. It made the A6 a lot more responsive and for the most part almost eliminated the gear hunt delay along with the clutch pack problems which was most annoying and detrimental to the performance of the car.

I can only hope they have continued to version this out until now they have it just right. Because from my understanding it's the same damn tranny.

Reiterating, when it comes to corvettes I prefer to remain grounded.

Shaka

I don't think the term, 'pre loaded' is quite correct or at least it can be misinterpreted. The gear combo selection for the next up or down shift, is staged. The clutch chamber begins pre or de pressurization in advance of the shift.

~Stingray

Does anyone know why GM put a 6 speed auto in and not a 7 speed auto like the manual?

dcbingaman

Because when your LT1 engine torque curve is as flat as a pool table any more than 6 speeds is overkill - manual or automatic !! Also, it was already in the GM parts bin, (6L80 from the C6, Camaro, etc.).

GZire

What a single clutch direct shift gearbox?! Some here might string you up for saying that.

Slynky

Not that anyone wants to hear it but I would hope autos would pass manuals in every aspect pretty soon.

In 2009 when the new 370Z came out, its 7-spd auto outperformed the 6-spd manual pretty easily. From "Car and Driver":

http://www.caranddriver.com/reviews/...take-road-test

Though I know it's more fun to drive the stick, I would predict the days of manuals outperforming the auto are close to an end. Hopefully, for the '14 'Vette, too. (or the '15).

Shaka

F1 cars seem to do pretty well with it. People don't understand that a DCT only uses one clutch pack at a time so you are lugging a heavy clutch and it's shaft around for no gain. Weight is the enemy in sports car design.
Better sell you PDK or DCT car before the warranty expires. The resale value of those cars will plummet.
READ MY LIPS, you will never see this contraption in a Vette.
Lexus did it the right way for a high performance car.
Corvette has something up it's sleeve. Z06 sales were low because the was no auto option.

Thespian

"Rumor has it from pretty good sources, like Jalopnic and others, that a pretty fancy 8sp. auto is in the works for 2015 C7"

... I'm really hoping this is the case !!!

jkcam6017

What will be the advantage of an 8 speed A/T over a 6 speed A/T?

Shaka

The engine stays at idle 'til 70. 30 mpg. The 4 speed is faster than the 6 speed auto according to Tadge.

sam90lx

Getting rid of the A6!

b4i4getit

The A6 has been here for too long. Give us a state of the art transmission GM.

JCtx

You meant 'Aisin', right?

That has been the case for a while man, except in cars with crappy (performance) transmissions, like the Vette . As soon as GM puts a worthy tranny in the Vette, it'll smoke the manual as well. Having said that, I just don't find the pleasure of driving an auto sports car, so for me is either manual or nothing. And yes, I know those days (or years) are numbered . My last sports car might be a new Cayman S. After that, might as well buy a high-performance sedan, and enjoy its other benefits. Can't really enjoy a sports car where I live anyway. Have a good one folks.

JerriVette

Who knew the A6 c7 z51 mrc npp auto review would be in such demand.

I bet its awesome.

Lots of forum owners have them on order...

What till they get to the strip...

I believe the a6 has launch control as well.

Guys like Bill will fill us in! Street driving,etc..