uae_83

I think this explains why they used the 6-speed auto
http://www.corvette7.com/c7-corvette...ission-chosen/

SCM_Crash

Link doesn't work. I went looking for the article, but didn't find it in a 2 second search. (Limited time. LOL)

uae_83

sorry
here it is

"Some interesting bits:

He explains why the choice to go with a 6 speed automatic transmission (and not 8 speed) - see 10:30 into video. Basically reason is that the 6 speed is good for high torque engine like the LT1, while fitting an 8 speed just adds weight and mass.

Also says that they haven't shared everything about the car yet (woohoo!)."

jimmyb

Not to rain on the parade but this video is almost 7 months old now. I am pretty certain we know all there is to know about the 2014 Corvette.

Also, I think Tadge is towing the company line about the 6 speed auto (the 8 speed isn't ready yet). It would not surprise me a bit if the new 8 speed auto goes in the C7 in 2015 or 2016 model years.

Jimmy

Bill17601

If you want to understand why high torque and high powered engines- are quicker with less gears , study the automatics in drag racing. Changing gears in a 450 ft lb engine is a waste of time. The purpose of adding all the gears is for little engines to stay in their narrow power ranges.but like horsepower numbers, the number of gears is a bragging point. Corvette had to go to 7 speeds because of Porsche. A Porsche needs more gears to stay in the power band.

If it makes you happy GM will go to 8 speed autos. My 4 speed automatic C5 is quick with its LS3 engine..

04_Z06_CE

i guess i dont care 6 or 8 speed but rather how it shifts. Most GM autos Ive know have been pretty ****** slushies.

MikeyTX

skip3389

Does anyone know if the A6 in ZL-1 camero is the same as the one that will be in the C7?

Goaty

Really? I've been very happy with the autos in my GM cars, formerly an 04 GTO and a C5 Vette, now a '13 C6. What is ****** about them? Not being a smart ***, just curious.

$$$frumnuttin'

I think he means ******= chitty.

Speednet

Actually, I think it has more to do with gas mileage than some kind of competition with Porsche. The new seventh gear is an ultra-tall overdrive gear -- the lower 6 gears were not compressed into a narrow power band. Porsche may need to do that, but Corvette does not.

BRCC

In essence the ZL-1 and CTS-V share the same engine (LSA) and the same Automatic transmission 6L90, so far the only thing that they show for the C7 is the 6L80, that is according to the current order guide. The 6L90 is rated at 531 Lbft, the 6L80 is rated at 439 LbFt, I would have to assume there is going to be some changes to the 6L80 to beef it up.

robvuk

There's a point of diminishing returns on any engine with the number of gears needed to keep the power up. The more broad your torque curve, the less gears you need.

For those who don't understand this, contemplate the extremes in both directions. You have a 20 speed transmission so you can keep your porsche at its narrow peak horsepower 3 times as long but you spend 3 times more time shifting and significantly more weight (rotating weight at that). The other direction you have an engine that produces the same rpm at all rpm's with only one gear. No shifting no additional weight.

sam90lx

2015 = 8 speed.

jschindler

Gee, a six speed is better for the torque of the car....but please don't ask me to explain why we went to a seven speed manual.

jschindler

Bill, do you really think there is some correlation between what is good for purpose built drag cars and street cars that have a whole lot of other conditions and parameters to deal with? And do you really think buyers of Corvettes will not buy a car because it has less gears than a Porsche? If that's the case, they would have done better to offer a DCT because manual transmission Porsche's are damn rare - even with the new seven speed.

Part of what more gears does is not for performance, but for fuel economy. It works. Look at cars that have the exact same engine and everything else, but went to a transmission with more gears. In every case they have a higher CAFE rating.

Skullbussa

TRANSLATION:

GM couldn't source or engineer their own 8-speed auto in time for the C7 release window.

While there is added mass and expense with an 8-speed auto (duh), there is also gained efficiency and performance. Yes, a torquey engine like the LT1 has less need for more gears than a 3-liter V6, but it could still benefit from the transmission.

And Car and Driver and others have already reported that new 8 speed auto transmissions will be offered for 2015 or 2016 model years. It's not hard to believe, this is the way every automaker is going in order to maximize MPG in their fleets.

Of course, what really interests me is whether or not they will offer the dual-clutch transmissions in the base Corvettes or if they will reserve that for the Z06 and ZR1 models.

FloydSummerOf68

It's all horse ****....they have the 6 speed because they don't have anything else ready yet.

The 6 speed would be ok if it didn't shift like a lazy old lady. The reason the auto ZL1, C6 and CTS-V are bashed so much is because of the lazy transmission. Compared to what comes in other cars these transmissions are pretty poor

It's the reason I'll be getting the manual C7....the auto C6 was such a disappointment.

sam90lx

BuckyThreadkiller

Quick isn't the objective for this gearbox. What's your highway mileage?

The additional gears won't be much for acceleration and straight line performance, it's for improved fuel economy.