UPDATE: After reaching out to Chevy PR for clarification, we now know that the 16/29/20 City/Highway/Combined mile-per-gallon ratings are for the standard Corvette with the new eight-speed transmission, while the 0-60 and quarter-mile times are for the Z51-equipped car using the new trans. The company does not yet have mpg estimates for the Z51/8AT combination.

The Chevrolet Corvette Stingray is already one of the best performers in its class and price range, and Chevy is making it even better for the 2015 model year with the introduction of a new, eight-speed automatic to replace the previous six-speed. The updated transmission isn't exactly news, but the Bowtie brand is finally telling customers why the two extra gears are so important. Autoblog will have driving impressions of the 2015 up later today, but for now, you can snack on this delicious morsel of info as an amuse-bouche ahead of our full impressions.

The eight-speed carries an EPA-estimated rating of 29 miles per gallon highway, a 1-mpg improvement over the previous automatic, and the 16-mpg city and 20-mpg combined figures remain the same as before. According to Chevy, part of the improvement comes from a new 2.41 rear axle ratio that has the engine turning 8 percent less at 70 miles per hour. Though, Z51 models keep their 2.73 ratio at the rear.

However, it's not all about eking out slightly better economy, as the eight-speed also makes the Stingray even quicker than before. The gearbox hustles the 2015 'Vette to 60 mph in 3.7 seconds, a tenth better than with six gears. The run through the quarter mile also drops a tenth to 11.9 seconds. The boost in performance comes thanks to a more aggressive first-gear ratio than before, the company claims.

Of course, not everyone wants an automatic, even an improved one, so for those who want to row their own gears, the seven-speed manual is still available too. Scroll down to read Chevy's full announcement and look forward to our Quick Spin coming soon.
Show full PR text
8-Speed Automatic Makes Corvette Faster, More Efficient

DETROIT – The all-new, paddle-shift eight-speed automatic transmission makes the 2015 Corvette Stingray faster and more fuel efficient, with 0-60 acceleration of only 3.7 seconds and an EPA-estimated 29 mpg on the highway.

"The Corvette Stingray is a great example of how we are leveraging engineering and technology to improve both efficiency and performance," said Mark Reuss, GM executive vice president, Global Product Development, Purchasing & Supply Chain. "No other car can match 460 horsepower, 0-60 mph in better than 3.7 seconds, and 29 mpg on the highway."

The Stingray's 0-60 performance is 0.1-second quicker than the previous six-speed automatic, contributing to a quicker quarter-mile elapsed time of 11.9 seconds – a 0.1-second improvement over the six-speed auto.

Its 29-mpg highway rating represents a 3.5-percent increase over the six-speed. New eight-speed models are EPA-rated at 16 mpg in the city and 20 mpg combined.

In fact, the Stingray's stingy fuel consumption on the highway is not only better than sports car competitors such as Porsche 911 Carrera (28 mpg), Audi R8 V-8 (20 mpg), Jaguar F-Type R (23 mpg) or Nissan GT-R (23 mpg), it tops conventional cars with smaller engines, like the Subaru Outback six-cylinder (27 mpg), Volkswagen Passat six-cylinder (28 mpg) and Mercedes-Benz C350 coupe (28 mpg).

The greater performance and efficiency enabled by the available, GM-developed Hydra-Matic 8L90 eight-speed automatic is due primarily to its 7.0 overall gear ratio spread, which enhances off-the-line performance with a more aggressive first gear ratio – 4.60 vs. 4.03 on the six-speed – helping achieve the quicker 0-60 time. It also delivers world-class shift times that rival the best dual-clutch design.

Combined with a new, numerically lower 2.41 rear axle ratio vs. the 2.56 gear used with previous six-speed automatic models, engine rpm is reduced by 8 percent (123 rpm) on the highway at 70 mph. The lower engine speed reduces fuel consumption. Z51-equipped models retain a 2.73 rear axle ratio.

The new paddle-shift eight-speed automatic complements the performance generated by the Corvette Stingray's LT1 engine – rated at 455 horsepower or 460 horses with the available performance exhaust system – which uses advanced technologies including direct injection, variable valve timing and Active Fuel Management (cylinder deactivation) to make more power with less fuel.

Advanced composite materials in the body structure and a lightweight aluminum frame, as well as aluminum and magnesium suspension components, support the Corvette's efficiency with a low curb weight of only 3,298 pounds /1,499 kg (Stingray coupe). They also enhance performance by giving the Stingray an excellent power-to-weight ratio of 7.25 – or one horsepower for every 7.25 pounds of mass. That's better than Porsche 911 Carrera's 8.7 ratio and Audi R8 V-8's 8.3 ratio.

For those who prefer a traditional manual-shifting driving experience, the 2015 Corvette Stingray is available with a seven-speed manual that delivers 0-60 times of 3.8 seconds and EPA-estimated 29 mpg on the highway.

Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 140 countries and selling more than 4.9 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature spirited performance, expressive design, and high quality. More information on Chevrolet models can be found at www.chevrolet.com.

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  • 19 Comments
      thequebecerinfrance
      • 9 Months Ago
      Purists will have a fit about having an automatic transmission in a sport car. I, for one, am tired of manual transmissions after 25 years of using them daily. A good, quick, smooth transmission with paddles can be a joy to drive, especially the new ones.
      Hazdaz
      • 9 Months Ago
      I still would pick a MT.
      Sergey R
      • 9 Months Ago

      I like this new Vette! Looks like Ferrari. I see lots of these new Stingrays here in Miami. Need to add that exhaust sound is good too.

      Jason
      • 9 Months Ago

      Actually somewhat surprising and disappointing with regards to the fuel economy improvement vs the 6-speed. (I'm sure adding fuel to the fire for critics of the increased number of speeds). But more important will be the performance reviews of the transmission vs the 6-speed, and further against benchmarks like the Nissan and Porsche DCT. I suspect the new 8-speed will offer quick enough and direct-feeling shifts to make it an appropriate choice even for performance-minded customers, where the 6AT did not.

        mitytitywhitey
        • 9 Months Ago
        @Jason

        I've often wondered why 'overdrives' were never spaced far from the non-overdrive gear set.   

        It's not like 6th gear can't be modified to be as far from 5th on a 6-speed as it is on an 7-speed. 

        You might have to rev 5th more to get into a really tall 6th as opposed to going 5-6-7-8, but didnt GM create 'skip shift' for just that purpose?  It's not like GM LS drivers haven't been forced to make big jumps in gearing before in order to 'save gas. '   

        It was never a big deal to 'skip shift' an LS, I found,  because torque.  

          Jason
          • 9 Months Ago
          @mitytitywhitey

          For an MT... you're right. But for a 6-speed, 7-, or 8-speed planetary AT, you can't just adjust one ratio without affecting the rest of the gear ratios. One of the key enablers in the trend to 7, 8, 9, and 10-speed AT is actually nothing more than effective computer calculations to derive useful combinations of the ratios, using practical and feasible gearsets. This seems easier than it sounds, much like how just three standard 2x4 Lego blocks can be configured in 1560 different combinations. This is something a lot of people don't realize, and part of the reason people jump to the conclusion that an 8-speed is inherently more complicated than a 6-speed (it may not be).

          Applying these useful ratio steps to a wider total range or ratio spread is in fact how some of the fuel economy gains can be realized. As some have probably been right to point out, the gain in spread compared to 6-speeds (for these 8-speeds) is not that much, compared to the jump from 4 to 6-speeds, so perhaps I should not have been as surprised at the MPG results. But I was hoping for more internal efficiencies as well.

      carguy1701
      • 9 Months Ago

      I wouldn't expect the Z51 ratings to be much different from the standard car.

      amge5.5
      • 9 Months Ago

      The numbers are not all that great for a light 2 seater, they are good but I was expecting them to do a little better than 1mpg gain on highway with the new C7.  

      lrx301
      • 9 Months Ago

      GM number is always fishy. Also, the Corvettes I met on road were always slow moving with old men behind wheels.

        cfphelps
        • 9 Months Ago
        @lrx301

        Corvette's have always been able to hit and exceed their MPG numbers.

      Emilio
      • 9 Months Ago

      29mpg huh??? Haha!!! What, going 40mph??? 

      Mbukukanyau
      • 9 Months Ago

      The most amazing feature of this box is It   delivers world-class shift times that rival the best dual-clutch design.

      AcidTonic
      • 9 Months Ago

      Such high gearing...... does it still take over 10 seconds to go from 60mph to 70mph in top gear like the last review mentioned?

        carguy1701
        • 9 Months Ago *Edited*
        @AcidTonic

        And what retard is going to attempt that?  Seriously, that's why kickdowns exist.

      Tiberius1701
      • 9 Months Ago

      What is it with GM and having to plaster the latest advancement (power brakes, 4 wheel disc, anti-lock brakes, eight-speed) on pedals, door handles dash placques and now shift knobs??? This has gone on for decades!!


       

        Jason
        • 9 Months Ago
        @Tiberius1701

        I understand your point and yeah, I agree they do it as poorly as anyone. At one point I recall they has a kind of cool infinity type "8" trademark out there for these transmissions but the clunky "8-Speed" on the shifter will just look dated and passé in 20 years. You're right on.

      SothyF
      • 9 Months Ago

      No paddle shifters?  I mean vettes going Euro-style might as well add that in.

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