= 2015 Stingray Eight-Speed Auto =

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08-24-2014, 08:10 AM

Space

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= 2015 Stingray Eight-Speed Auto =

First Drive: 2015 Chevrolet Corvette Stingray Eight-Speed Automatic
Hi Member's, do you like it ? Do you want/desire one ? Post & let us know what you think ?

By Nate Martinez |`Space August 24, 2014 |

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We know, we know. Manuals rule. Automatics drool. It’s one of the core arguments among the purest of the purists. But for GM and its crown jewel, the Corvette Stingray, this dispute is not if an automatic will be offered, but rather, which automatic will be offered. Facts are facts: 63% of the 37,000-plus 2014 Corvettes sold had a six-speed automatic. The rest, well, you know what they had.More on Motortrend.com:

2015 Chevrolet Corvette Z06 Pricing Announced

Such telling data is precisely why GM is sinking copious time, money, and effort into an updated eight-speed gearbox. It’s dubbed the Hydra-Matic 8L90 and it’s all GM, baby. More than 24 patents were awarded to the company’s brainiacs during its creation. It’s more efficient and more capable than the current six-speed 6L80 it replaces. But, before we get into its specifics, there’s another reason why the 8L90 came to fruition: Z06. Yes, if you haven’t heard by now, the forthcoming Z06 will have a torque-converter-packing, planetary automatic transmission option.

“Really, this transmission was engineered around the upcoming Z06,” admitted Tadge Juechter, Corvette chief engineer. “Corvettes are extremely tightly packaged with the transmission in the back, so we’re bearing-limited in longitudinal `space. So essentially, this transmission is custom designed for our package space, as well as the performance capabilities of the car. Our priority was that it had to be able to withstand the 650 foot-pounds of torque and 650 horsepower.”More on Automobilemag.com:
2015 Chevrolet Corvette Z06 Priced at $78,995, Convertible at $83,995
Juechter and his team turned to Kavoos Kaveh, global chief engineer for GM’s eight-speed automatic, to take on the task of building not just a gearbox for the Z06 and its crazy power, but a gearbox for the Stingray, other Corvette variants, and GM’s 6.2-liter-powered SUVs and trucks.Kaveh’s goals were simple, at least on paper: It had to be more efficient; it had to fit inside the Corvette chassis’ already extremely cozy constraints; it had to be lighter; and, if that wasn’t enough, it had to withstand all the stresses that come with the various applications.More on Automotive.com:
2015 Chevrolet Corvette Receives New Options

Amazingly, Kaveh and his team worked within the 6L80’s existing space. They gave the 8L90 smaller step sizes (for better off-the-line go); four simple gear sets with a 7.0 overall gear ratio spread (4.56:1 first gear); a chain-driven, off-axis, binary vane pump (high output for performance, low output for fuel economy); synthetic Dexron 6HP fluid; and a torque converter turbine damper (to improve low-speed clutch smoothness). Just two open clutches reduce power flow losses now.

Its updated Gen II controls include a T87 electronic control module (four times faster than Gen I), three speed sensors for more accurate multi-step shifts, and high and low variable force solenoids to better the accuracy of clutch pressure. The gearbox is eight pounds lighter due to its liberal application of magnesium and aluminum. Its piston housing and channel plate are made of the former, pricey metal; its case with bell housing, clutch pistons, input carrier, and rotating clutch housings are all aluminum. Its input carrier shell uses high-strength low-alloy steel to shed mass.

The end result is a Stingray that is up to five percent better on GM’s highway fuel economy test cycles in Tour mode (not Eco mode). That means 29 mpg — or 29.4932 mpg, if you want to get exact — compared to this year’s 28 mpg EPA rating. “We have an Eco mode in the car, and you have an Eco mode on the label, but we expect more people to drive in Tour, Sport, Track, so we label the car based on the Tour mode,” explained Juechter.He says that with additional fine tuning and testing, they’ll get to 30, no problem. “We’re going into production, so we don’t have time to tweak or retest for this year, so we’re going in with a 29 (mpg) label. In Eco Mode, it would do solidly in the 30s. And probably next year, we’ll come back and tweak the calibration of the transmission to (officially) get to 30 miles per gallon. In Corvettes, you can actually get the number that’s on the label.” Still, as is sits, that means it’s as efficient as its EPA-rated 2015 counterpart having a seven-speed manual.But get this: It’s also quicker. In fact, the 8L90-equipped Stingray is quickest Corvette in a straight line (until the Z06 arrives) with a 0-60 mph dash in 3.7 seconds and quarter-mile run 11.9 seconds (no word on trap speed). Added Juechter: “(Those times) should be easily replicated. We’ve had cars in the 3.6s — even some cars in the 3.5s, but we’re going to market with the 3.7 as the performance (figure).”

Wide open throttle second-to-third upshifts are 0.08 seconds quicker than those of its benchmark, Porsche’s seven-speed PDK, says Kaveh (0.45 vs. 0.53). Downshifts from WOT at 60 mph in Sport mode are just as quick (0.95 seconds) too. The PDK also nips at the Hydra-Matic’s heels during WOT first-to-second upshifts (0.49 vs. 0.52). To experience the gearbox’s character, Chevrolet set us loose on its 2.9-mile twisty, undulating, blind-corner-filled track at the Milford Proving Grounds. Nil-to-wee sprints in Track mode, automatic shifts, were quite telling: The gearbox knocked off gears at its indicated 6500 rpm abruptly, spectacularly, with an accompanying violent explosion that only a 6.2-liter V-8 with quad pipes could produce. As corners neared, downshifts were again crisp. Deep inside corners, gears held with no moments of confusion or hesitation — it was as if the CPU was more intuitive than reactive; more organic than robotic — which ballooned my confidence and allowed me to pinpoint the longish nose.While Chevy’s numbers beg to differ, the 8L90 in Track mode simply didn't feel as quick as the PDK when operated via its plastic paddles. Don’t get me wrong, clicking off a WOT upshift is a glorious, stupidly fast affair. It is much the same for downshifts. Yet, Porsche, with its well-honed cohesion of an extra clutch and different structural packaging, still has the upper hand in smoothness and feel while on track. Even still, the 8L90 was impressive, especially when off the track. We drove more than 40 miles in highway and city settings around Milford. Smoothness was the name of its game. Intuitiveness was too. Multi-step highway passes in automatic mode required no pauses on its part. The ‘Vette just flew. Then it calmly upshifted into a gear best suited for casual cruising. So, you may be thinking, why no dual-clutch? There were a few reasons why, says Juechter: Structural tunnel packaging, vehicle balance, durability, and fuel economy. It needed to be shared within General Motors as well. “There was no DCT or advanced transmission in the world that would just fit in that package and that would live behind the upcoming Z06 with 650 horsepower. So we were faced with a conundrum: We could have designed our own DCT, which could have worked for us, but it would not be useful anywhere else in General Motors. It wouldn't be good for heavy duty trucks and things like that. DCTs are great for some things, but they’re not great for a lot of clutch slipping.

One of the big fuel economy advantages of this car is being able to run in four-cylinder mode. DCT are not terribly compatible with AFM (Active Fuel Management). So having a torque convertor as a torsional damper in the system actually helps to use four-cylinder operation. That’s a big fuel economy enabler. Between those two factors, we, GM, elected to say ‘Ok, were going to do a planetary eight-speed transmission with a torque convertor, but we’re going to model it after DCT performance characteristics.’’ That election resulted in a very stunning, very capable, lightning-quick automatic transmission. It is gearbox that will surely have potential buyers scratching their heads, wondering if a five-, six-, or seven-speed manual is their way to go. Now, that’s saying something.

Corvette Stingray, Eight-Speed Automatic

BASE PRICE $55,500 (est) LAYOUT Front-engine, RWD, 2-pass, 2-door hatchback, convertible ENGINE 6.2L/455-hp/460-lb-ft OHV 16-valve V-8 TRANSMISSION 8-speed automatic CURB WEIGHT 3450 lb (MT est) WHEELBASE 106.7 in LENGTH x WIDTH x HEIGHT 177.0 x 73.9 x 48.6 in 0-60 MPH 3.7 seconds EPA CITY/HWY FUEL ECON 16/29 mpg (est) ENERGY CONSUMPTION, CITY/HWY 211/116 kW-hrs/100 miles (est) CO2 EMISSIONS 0.97 lb/mile (est) ON SALE IN U.S. Fall 2014

Last edited by Space; 08-24-2014 at 08:35 AM.

08-24-2014, 08:26 AM

SSilver

Join Date: Apr 2009

Location: Aurora, IL

Posts: 379

08-24-2014, 08:37 AM

Space

Thread Starter

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Thanks for your Post/Vid

Thanks much for adding to this thread.
Super `Vid 4-Sure

I desire one 4-Real

"2 dare 2 dream in SpaceVision"

08-24-2014, 08:41 AM

Space

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Eight *8* second Vette (WOW)

08-24-2014, 10:16 AM

SSilver

Join Date: Apr 2009

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Posts: 379

That's not a C7...but it sure is quick

08-24-2014, 11:56 AM

Space

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Join Date: Jul 2008

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U never know what U will find in a post unless you click it (lol)

Quote:

Originally Posted by SSilver

That's not a C7...but it sure is quick

LoL `Silver, I knew that it wasn't a C7, but just a 8 sec Vette (WoW)....

Below is one that would fool a lot of people `if it pulled up to you @ a traffic light & a clear road ahead...

To me it was worth a click & a Big Laugh >

Check it out `if you have the time to Laugh > Enjoy