A favorite of the vehicles I drove last year, the Chevy Corvette Stingray is easily one of the best performance bargains on the market. And I’m not alone in thinking so.
Engine: 6.2-liter V8 with 460 HP and 460 lb-ft of torque.
Transmission: Eight-speed automatic.
Fuel economy: 16 MPG City, 29 MPG Highway.
Price: Starts at $54,995 after destination charges.
Even after winning the 2014 North American Car of the Year, the folks at Chevrolet weren’t about to pat themselves on the back and spend a few years resting on their laurels. No, for 2015, significant improvements are being made to the Stingray in only its second year on the market. New are enhancements to the rev matching precision of the seven-speed manual transmission, the addition of an optional performance data recorder and an all-new eight-speed automatic.
Dubbed the Hydra-Matic 8L90, the eight-speed is an in-house GM design that replaces the old six-speed in the Stingray and will even find its way into the upcoming Corvette Z06, which means the 8L90 needs to be able to handle upwards of 650 lb-ft of torque. More than that, the new eight-speed also needs to be flexible enough for use in pick-up trucks and SUVs as well as sports cars and must be able to fit into the same physical space as the old six-gear transmission.
More Gears, Lighter Weight
By using clever packaging, Chevrolet claims to have succeeded with all these demands. Add in abundant use of aluminum and magnesium and the new eight-speed transmission actually weighs in at eight pounds less than the outgoing six. Equipped with four gearsets and five clutches, the overall ratio for the new-eight speed automatic expands to 7.0, featuring a shorter first gear (for better acceleration) and taller final gear (for improved fuel economy).
This adds up to a 0 to 60 MPH time of 3.7 seconds according to Chevrolet which is 0.1 seconds faster than the old six-speed automatic and the current seven-speed manual. Quarter-mile times have also been shaved by 0.1 seconds, now listed at 11.9 seconds. Furthermore, wide-open throttle upshifts are said to be executed up to 0.08 seconds quicker than those done by the dual-clutch transmission in the Porsche 911.
All of these facts and figures are impressive, but how does the new eight-speed automatic perform in the real world? To find out, Chevrolet brought us to the company’s proving grounds in Milford, MI to test the 2015 Stingray on the track and the street.
Real World Testing
With the threat of a Michigan monsoon looming overhead, we rushed out to the Milford Road Course (MRC) to put the 2015 Chevrolet Corvette through its paces. For those unfamiliar, the MRC is 2.9-mile racetrack built inside a 2.0-mile oval. Designed to mimic many of the best aspects of tracks around the world, MRC features hills, dips, chicanes, blind corners and even a near vertical “toilet bowl” 180-degree corner.
To begin my first lap, I did what any red-blooded car lover would do when given the keys to a brand new Corvette; I mashed the accelerator pedal. Instantly the car leapt forward in a V8 snarling furry. There is no hesitation or torque converter delay with the new eight-speed automatic – just instant response. As I accelerated toward the first corner at well over 100 MPH, upshifts were firing off lightning quick, just as advertised.
As I approached the first corner, standing on the brakes, the engine begins to do near redline, rev-matching downshifts. True I’m running in “Track” mode, but there is no other input from me. The car just acts like it’s supposed to on a track, firing through the gears as needed. I run another five shaky laps trying to figure out the undulating, challenging course. During this time I’m anything but smooth, but the transmission is only caught out in the wrong gear twice and both times for less than a second.
Let the Transmission Handle the Shifting
Needless to say the new eight-speed automatic works at the track, but this should come with a caveat – don’t touch the paddles. The software engineering has been so well sorted out that the computer is calling for gears in advance to the driver actually needing them, so when the change occurs it’s at the exact right moment. Since this is a “regular” automatic, using the paddle shifters to “manually” select a gear is followed by a lengthy delay.
It’s the one thing a conventional automatic cannot match compared to a dual clutch transmission (DCT), the response time from a driver’s input to the physical gear change. Sure the new eight-speed can change gears lightning quick, but a DCT has already pre-loaded the next gear and can react to a new input much faster. I will say that response time does feel quicker from the Corvette’s eight-speed automatic than the eight-speed autos I’ve recently sampled, including in the Jaguar F-Type.
Efficient on the Street
Almost as if Chevrolet had paid off Mother Nature, the rain held off until the exact moment we finished our track drive. With a very wet street drive looming ahead of me, I decide it’s time to see just how efficient the 3,298 lbs. Corvette can be if driven softly during a mix of country back-roads and the freeway. After a short 19 mile drive, the Corvette reports an observed fuel economy average of 28.6 MPG. That is nearly as high as the 2015 Corvette automatics official highway rating of 29 MPG (the city rating is much lower at 16 MPG).
The reason behind this is two parts. First, the Corvette defaults into “Touring” mode upon start-up and all official fuel economy testing has been done in this setting. During my drive, the Corvette remained in the more efficient Eco mode the whole time, padding my numbers slightly. As well, Chevrolet engineers feel with a bit more tuning, the Corvette Stingray eight-speed could easily achieve 30+ MPG highway during testing. I’d expect to see the official ratings to increase in the next year or two.
Chevrolet has not reinvented the automatic transmission, but what the company has done is taken a great car with a good transmission and made it better. With more performance and better real world fuel economy, there isn’t much to complain about with the new Hydra-Matic 8L90 automatic. If it were my money though, I’d still equip my 2015 Stingray with the more engaging seven-speed manual. But if an automatic is a must, thankfully the Corvette now has a really good one.