Looks Like The 2015 Corvette Is Getting An 8-Speed Automatic

"SonorousSpeedJoe" (SonorousSpeedJoe)
12/08/2013 at 22:35 • Filed to: 2015 Chevrolet Corvette, C7, Corvette, Stingray

History seems to be repeating itself with the 2015 Corvette. Just as the 2006 Corvette C6 swapped the 2005 C6's 4-speed automatic transmission for the 6-speed 6L80E automatic, the 2015 Corvette C7 will forgo the 2014 C7's 6L80 for an 8-speed "8L90" automatic. Per the abstract to this !!!error: Indecipherable SUB-paragraph formatting!!! paper:

General Motors shall introduce a new rear wheel drive eight speed automatic transmission, known as the 8L90, in the 2015 Chevrolet Corvette. The rated turbine torque capacity is 1000 Nm. This transmission replaces the venerable 6L80 six speed automatic transmission. The objectives behind creation of this transmission are improved fuel economy, performance, and NVH. Packaging in the existing vehicle architecture and high mileage dependability are the givens. The architecture is required to offer low cost for a rear drive eight speed transmission while meeting the givens and objectives. An eight speed powerflow, invented by General Motors, was selected. This powerflow yields a 7.0 overall ratio spread, enabling improved launch capability because of a deeper first gear ratio and better fuel economy due to lower top gear N/V capability, relative to the 6L80. The eight speed ratios are generated using four simple planetary gearsets, two brake clutches and three rotating clutches. The resultant on-axis transmission architecture utilizes a squashed torque converter, an off-axis pump and four close coupled gearsets. The three rotating clutches have been located forward of the gearsets to minimize the length of oil feeds which provides for enhanced shift response and simplicity of turbine shaft manufacturing.

The transmission architecture features a case with integral bell housing for enhanced powertrain stiffness. A unique pump drive design allows for off-axis packaging very low in the transmission. The pump is a binary vane type which effectively allows for two pumps in the packaging size of one. This design and packaging strategy not only enables low parasitic losses and optimum priming capability but also provides for ideal oil routing to the controls system, with the pump located in the valve body itself.

The transmission controller is externally mounted, enabling packaging and powertrain integration flexibilities. The controller makes use of three speed sensors which provide for enhanced shift response and accuracy. Utilization of aluminum and magnesium components throughout the transmission yields competitive mass. The dedicated compensator feed circuit, used in GM six speed designs, was supplanted by a lube-fed design in order to simplify oil routing and enhance shift response. Packaging is within that of the GM 6L80 design, allowing for ease of application integration.

The overall result is a robust, compact, and cost effective transmission which offers significant fuel economy and performance benefit, over its six speed counterpart, and shall provide an attractive balance of overall metrics in the automatic transmission market.

For fellow 'Mericans, I should note that 1,000 N•m of torque is roughly 738 lb-ft of torque. I first read about the 8L90 !!!error: Indecipherable SUB-paragraph formatting!!! .

[Photo Credit: !!!error: Indecipherable SUB-paragraph formatting!!! ]

DISCUSSION (28)

The Opponaut formerly known as MattP123 > SonorousSpeedJoe
12/08/2013 at 22:38

And the 04 GTO got the 5.7 while the 05/06 got the 6 liter. And the 04/05 CTS-V got the 5.7 and the 06/07 got the 6 liter. Seems typical of GM.

Reigntastic > SonorousSpeedJoe
12/08/2013 at 22:52

To be honest, I don't really care. I laugh when I see these with the autotragic.

Kailand09 > SonorousSpeedJoe
12/08/2013 at 23:17

Interesting on the torque capacity...

MtrRider Just Wants Doritos > The Opponaut formerly known as MattP123
12/08/2013 at 23:20

Ford does it too. Remember to 2010 Mustang, then the 2011 got the 5.0 and 3.7? And the 2009 F150 had the old engines, then in 2011 they got all new engines?

PS9 > Reigntastic
12/08/2013 at 23:51

Of all the cars to get with an auto, why this?

Boxer_4 > Reigntastic
12/09/2013 at 01:06

Believe it or not, the Corvette was not always available with a manual. The 1953-mid 1955 C1 Corvette was only available with a 2 speed automatic. You could potentially argue that a "real" Corvette should have an automatic. "Real" meaning as close as possible to the original model, as the original models of everything around here quite often are used as the benchmark to compare the current and future models.

Now, that fact doesn't really mean anything with regards to modern Corvettes, and I'm not trying to defend automatic equipped Corvettes. However, the automatic does have a bit of history in the Corvette.

Still, when ever I see an automatic equipped Corvette, I always wonder "Why would you do that?"

SLR999 > Reigntastic
12/09/2013 at 02:15

Provided it's reasonably sophisticated (a la ZF 8 in RRs, Jags, and MOPARs), this makes the C7 a much more attractive proposal to the right-foot-impaired.

Axial > SLR999
12/09/2013 at 02:30

You mean left foot impaired? Or are you one of those people who lives in a wrong-hand-drive country? Actually, and I've never thought about this before, are the pedals in RHD countries also reversed from LHD or are they the same?

Axial > SonorousSpeedJoe
12/09/2013 at 02:32

Looks like all the speculation at CF last year was right on the money.

SLR999 > Axial
12/09/2013 at 03:06

Wow. This is what 16 hours of staring at eq'ns does to you.

AFAIK left is always clutch, even in RHD.

Atomic Buffalo > Axial
12/09/2013 at 03:10

Yeah, this surprises absolutely no one who's been following C7 development.

We all knew Tadge's defense of the six-speed auto was just stalling. (There's a torque converter joke in there somewhere, but I'm too lazy.)

Axial > Atomic Buffalo
12/09/2013 at 03:40

The difference is that up until the release, everybody thought it was going to be an Aisin-sourced gearbox (yuck). Then reports started showing up saying GM was working with Ford to develop 8-, 9-, and 10- speed boxes.

Reigntastic > PS9
12/09/2013 at 09:36

Exactly. I'd want to actually drive this beast.

Reigntastic > Boxer_4
12/09/2013 at 09:38

I'm the type to argue for progress, not stagnation, so I must say I'm glad that the 2015 'Vette won't be coming with a 2 speed auto, but I generally don't care about keeping new models original.

Generally I view the automatic equipped 'Vettes as cars for posers.

Reigntastic > SLR999
12/09/2013 at 09:40

I'd still rather use my antiquated 7 speed, call me old fashioned. Automatics for these never seem to hold their value as well (at least speaking from history at this point) and I'm not sure why.

MooseKnuckles > Axial
12/09/2013 at 11:08

They are (with Ford), development of the trans together then software has to be done separate. I think it's an 8spd fwd trans and 10spd rwd.

MooseKnuckles > SonorousSpeedJoe
12/09/2013 at 11:09

So is this the same 8spd that is in the CTS?

SonorousSpeedJoe > MooseKnuckles
12/09/2013 at 11:59

No, I believe the CTS uses the Aisin TL-80SN.

Atomic Buffalo > Axial
12/09/2013 at 12:16

Not everybody. Rumor was it would be an Aisin-sourced box for one model year as a stopgap until GM's own 8-speed was ready, since Aisin had a unit that seemed compatible. That seemed a little sketchy to some, even if the gear ratios matched and a lot of the programming carried over. After all, the one-year-lame thing is so deeply ingrained into the GM psyche that even bankruptcy couldn't be counted on to purge it completely, and we had the 2005 four-speed as a recent example that didn't burn them too badly.

What's interesting about this new tidbit is the torque-handling. It may just be a truck thing, or a design-maximum thing, and not planned for higher-powered Corvettes... but it might be a big middle-finger to the idea of a Corvette DCT. As a fan of human-modulated clutches even at the expense of lap times, I don't really care, but as I'm sure you know there was a lot of disappointment when C7 arrived with no DCT, and more than a few people think it can't be world-class without one.

Axel-Ripper > PS9
12/09/2013 at 12:20

Faster on track, no matter driver skill.

SLR999 > Reigntastic
12/09/2013 at 12:25

On the fence. I love manuals, but would tend towards an automatic if it was my only car.

Reigntastic > SLR999
12/09/2013 at 13:30

See, I just don't understand why. My only car is a manual currently, and it's a breeze. Really the only drawback is that I have to use my built in bluetooth instead of being able to yap on my phone directly.

Is it just laziness?

brass1223 > SonorousSpeedJoe
12/09/2013 at 14:10

as long as they offer a manual transmission, i say let the lazy people join in on the fun!

A.DrewWilliams > SonorousSpeedJoe
12/09/2013 at 15:07

Kinja'd!!!

Of course. How else are they going to sell in large numbers to their main demographic?

m.stallion > PS9
12/18/2013 at 17:21

i'm actually interested in purchasing a C7 in 2015/16. while i do like manuals more and have one now simply because they are more fun, honestly i prefer the stingray with a 7 or 8 speed sequential gearbox. read: NOT an automatic, but a paddle shifted smg or dual clutch sequential transmission. i know it wont be as fun but it will be simply amazing on track. but if the only other option is slushbox auto, 7 speed it is.

PS9 > m.stallion
12/18/2013 at 17:47

SMGs are automatics. Auto trans = Transmission capable of choosing its own gears. The only SMGs that can't are in actual racecars, so of the C7 got one, it would definitely have auto functionality.

m.stallion > PS9
12/20/2013 at 10:09

i prefer this. definitely not an auto (no fluid filled torque converter) but rather clutches with electronic+hydraulic actuation and control. this is similar to the transmisions found on the GTR and most of the exotics these days.

http://en.wikipedia.org/wiki/Twin_Clut…

PS9 > m.stallion
12/20/2013 at 10:14

Again, an 'automatic' is not defined by what machinery inside it enables it to choose it's own gears, but by the fact that it can choose it's own gears. In that, both torque converter driven transmissions and dual clutch transmissions are automatics, since they can both pick gears without driver input.