Chevrolet Corvette


Debut: 2013
Maker: General Motors
Predecessor: Corvette C6



 Published on 6 Nov 2013 All rights reserved. 


For most of the time during its 60 years history, Chevrolet Corvette was America's sole pure sports car. To this date it is still the only mass production sports car produced by Detroit, one that keeps American fighting with European imports like Porsche, Lotus, Jaguar etc. You can see how important it is in the heart of every American car lover.

Like the rest of the American auto industry, the Vette has undergone a long decline since the 1980s but it is now bouncing back. The outgoing ZR1 was a good sign that there is still life in the Vette if GM commits to it. The new 7th generation Corvette is even more promising. With brand new styling, new engine and new chassis, the C7 is a big departure from the outgoing C6, which was a mild evolution from C5. In terms of styling, it could be even the most radical Corvette since the 1963 C2. No wonder it reuses the legendary nickname "Stingray".


Since the 1984 C4, Corvette has never altered its styling much. Its general profile, its trademark wraparound rear window and quad-round taillights have been serving the car for nearly 30 years. Now all have gone. The C7 has a far more aggressive profile – a more flowing bonnet, muscular front and rear fenders, coke-bottle sides and a high-rising tail topped by a spoiler. A shark wide mouth opens at higher level than before, beneath which is a body-integrated lip spoiler. The nose is so clean and pure as it gets rid of signal lamps and fog lamps, which have been incorporated into the HID and LED headlights. The bonnet has deeper concaves and a more pronounced power dome with louvered ventilation, so it looks more dramatic. The polygonal taillights look more Camaro than Vette, but the centrally-mounted quad-exhaust are definitely spectacular. Sharp crease lines on the fenders and door sills add aggressiveness that missed out in the last 3 generations. Cooling has also taken a more important role. The hot air vents aft of the front wheels are visually enhanced. Louvered intakes are added to the top of rear fenders, drawing cold air to the oil cooler of rear transaxle. The resultant hot air exits from the outlets incorporated with the taillights. All were done with style.

Some may be disappointed that the C7 has lost its trademark feature – the wraparound rear glass screen has been replaced with conventional C-pillars and quarter windows. This also hampers its rearward visibility by a considerable degree. That said, the C7 is still significantly more striking to look than either its predecessors or most of its European counterparts. Most important, it is still unmistakably a Corvette!


The new LT1 small-block V8 keeps a displacement of 6.2 liters as well as outdated pushrod OHV 2-valve construction, but it is actually a clean-sheet design. It features variable cam phasing on its sole camshaft to advance and retard intake and exhaust valves in a continuous manner. Direct injection is another important new feature to save fuel, ditto the introduction of cylinder deactivation technology called Active Fuel Management or AFM, which switches the engine to V4 mode under light load. The LT1 produces a maximum 460 horsepower and 465 pound-foot of torque, compared to 430 hp and 424 lbft of the outgoing LS3. Its maximum rev is 6600 rpm, not bad for a pushrodder. Low to mid-range torque gets a more noticeable increase. From 2000 to 3500 rpm it produces an additional 50 lbft. Meanwhile, EPA-certified fuel economy is improved to 17 mpg city and 29 mpg highway – the latter is the best among performance cars with the north side of 450 hp.

There are two choices of transmission: the manual is a new Tremec 7-speed gearbox (it is the only 7-speed manual in the world beside the ZF unit of Porsche 911). Unusually, it offers rev-matching function like some clever automatic or DCT boxes. It utilizes a sensor near the gear lever to detect the gearchange, and the ECU is clever enough to predict the gearchange so to prepare for rev-matching, then it blips throttle automatically when gearshift is taken place. Rev-matching is available to both upshift and downshift. Another gearbox choice is the existing GM Hydramatic 6-speed automatic.



As before, the gearbox is a transaxle, i.e. it is integrated with the differential and sits at the rear axle. This arrangement enables the Corvette to achieve 50:50 weight distribution front to rear (note: Car and Driver measured an even better 49.4:50.6). The engine and transaxle are connected by a rigid torque tube made of steel. You might remember the last two generations employed aluminum torque tube to save weight. The new Vette has to turn to steel because the AFM's four-cylinder mode generates more vibration which needs a stronger torque tube to contain.

The suspensions continue to be double-wishbones (or "A-arms" in American terms) at all corners. They are again made of cast aluminum, but now the lower control arms are hollow, cutting 4 kg. The rear toe control links have switched from steel to aluminum and cut another 1 kg. In addition to the use of narrower wheels and tires, unsprung weight is considerably reduced. The ZR1's Magnetic Ride Control system, which uses Delphi's magnetorheological dampers to vary stiffness, is available as option. Now it is updated to the 3rd generation like Ferrari California. A dual-coil design improves its reaction response by 40 percent. Braking is provided by Brembo 4-pot brakes. The front and rear disc measure 345 mm and 338 mm on Z51 package. The Z51 package also sports a new active limited slip differential, which uses hydraulic clutches to control the torque split between the rear wheels for better traction and the desired handling characteristic.



The new chassis looks structurally similar to the old one, with a prominent backbone (transmission tunnel) and a pair of side rails connected by some cross members. However, where the old chassis was made of hydroformed steel frames, the new one is constructed from extruded and cast aluminum frames. Some parts, like the front and rear cradles, are made hollow to save further weight. As a result, the chassis is 45 kg lighter than before while its torsional rigidity is up by 57 percent. The steering mounting is also strengthened by 5 times to improve the accuracy of its new, variable-ratio electrical power steering.

As before, the body shell is largely made of SMC (sheet-molded compound) glass-fiber, but the new material has a lower density. The bonnet and targa roof panel are now made of carbon-fiber, whereas the underbody panel is made of carbon-nano composites, i.e. a blend of carbon-fiber and glass-fiber. Overall, the new body work saves 17 kg.

In spite of all these weight saving measures, the C7 actually outweighs C6 by 70 kg, tipping the scale at 1562 kg. Blame must go to the AFM hardware (which adds 18 kg), the steel torque tube (+7 kg) and the much improved interior and standard equipment. It is also slightly larger than the old car, being 60 mm longer and 33 mm wider. Wheelbase has been stretched by 24 mm to 2710 mm, while tracks are 20 mm wider.


As for electronics, the Corvette finally follows the industrial trend to offer a driver switchable control system called DMS (Driver Management Selector). By using the rotary knob located behind the gear lever you can change the driving behaviour among 5 modes - Weather, Eco, Tour, Sport and Track. They alter quite a lot of areas, namely throttle, AFM, automatic transmission, variable exhaust, electronic LSD, power steering, MRC, launch control, traction control and stability control.

Inside, the new Vette again favours a traditional twin-cockpit layout with removable hardtop, but materials are much more expensive, thanks to nicer leather upholstery, real alloy and carbon-fiber trim decors. Its main instrument has 2 half dials sandwiching an 8-inch LCD, which can be reconfigured to display different information, such as trip data, audio and sat nav in Tour / Eco / Weather mode, classic gauges in Sport mode and lap timer + gauges in Track mode. On the center console, there is another 8-inch LCD touch screen for the infotainment system. Color head-up display is another classy option.

On the Road

The biggest rival to Stingray is undoubtedly Porsche Boxster/Cayman. A heavily loaded Stingray costs about the same money as a mid-spec. Boxster S / Cayman S with PDK and PASM adaptive dampers optioned. On paper, the Porsche duo's 3.4-liter flat-six with 315/325 hp is no match with the American car's V8 power, let alone torque. However, many motoring writers would tell you a different story in the real world. Take the exterior for example, while the Stingray is far more head-turning on the street, the large and varying panel gaps on its plastic body reveal a build quality that is several grades below the laser precision of Porsche. The same can be felt when you slam or unlock the doors.



Get on board, you will be happy to see the C7 has put behind the cheap impression of the old car, and it finally gets its bucket seats right (a serious complaint for years), but the new cabin still looks and smells too plasticky, while the switch gears and fit and finish are nowhere as classy as Porsche. The cabin is more cramped due to the low roof and prominent tranmission tunnel. That said, the view over its heavily sculpted bonnet is definitely more spectacular, and it reminds you there sits a legendary small-block V8 up front. It might be already 50 years since the original Sting Ray, but the sense of occasion remains intact.

As before, the big V8 produces tons of torque and an angry, unmistakable soundtrack. It feels more eager than the old V8 at low rpm but it is not as explosive as the last Z06 unit at upper rev. Of course, it lacks the creamy, rev-hungry manner of Porsche. In fact, the power delivery manner of the LT1 is more familiar to loyal Vette owners than its new technlogy would lead us believe. The first set of road tests conducted by American magazines maybe not good indicators to its true performance, because they were done on GM's high-grip proving ground and, from our past experience, can never be repeated in subsequent road tests. That's why I would take Car and Driver's second batch of test data as reference: 0-60 mph in 4 seconds flat and 0-100 mph in just over 9 seconds. It is a little quicker than the Cayman S PDK tested by the same publication, but marginally slower than a 911 Carrera S PDK, Jaguar F-type V8 S and of course the mighty Nissan GT-R – admittedly, all these cars cost a great deal more to purchase thus should not be compared with the Corvette. Among its class rivals, the Corvette is virtually peerless in straight line acceleration. Ditto its estimated top speed of 190 mph.



To our surprise, its braking performance (with the Z51 pack) is just as good as Porsche, no matter measured distance, fade resistance or brake feel. The electrical power steering is superb, being linear, precise and offers good feedback. Less impressive is the 7-speed manual gearbox, whose gearshift is quite obstructive thus requires a deliberate hand.

With a far stiffer chassis, better weight distribution, wider tracks and improved suspensions, the C7 handles and rides a lot better. In fact, it has risen very close to the Porsche level. Its magnetic damping provides a firm yet composed ride. The alloy chassis doesn't shake or rattle like the C6, and the handling is no longer twitchy at the limit. Its Michelin tires provide tremendous grip and progressive breakaway, in addition to the precise functioning of electronic differential, it allows you to put down the power cleanly to the road and drive it very hard through corners. Admittedly, the power delivery isn't as linear as its smaller engine rivals, thus it still takes more learning and discipline to extract its maximum, but its behaviour at the limit is transparent and predictable. It should excel on roads as well as on tracks.

Ultimately, the Stingray still lacks the tactile control, razor-sharp precision and delicate feel of Porsche Boxster/Cayman S. It is also nowhere as nimble as the lightweight Alfa Romeo 4C. This mean it is still not our top choice of the class. However, the gap from class leaders is greatly reduced. Most important, it no longer feels cheap and rough. Now it is finally a desirable yet affordable choice to sports car lovers.
Verdict:
 Published on 11 Mar 2015
All rights reserved. 
Corvette Z06


I don’t quite understand why Chevrolet calls this Z06. Considering its supercharged engine, its weight (almost 200 kg more than the last Z06), its performance level as well as its relatively good road manner, it should have been the logical successor of ZR1. The only reason I could think of is that the ZR1 label could be reserved for another application – have you heard the rumor about a mid-engined super Vette? If true, that must be the most exciting news about American sports car industry. Right now, however, the new Z06 should give us plenty of excitement. Think about 650 horsepower and 650 pound-foot of torque, 0-60 mph sprint in not much over 3 seconds and a top speed of up to 195 mph. That’s the performance level of Porsche 911 Turbo S, yet a fully loaded Z06 costs just over US$100,000 or half the price of Porsche.

Yes, the top Corvette has always been known for superior bang for the buck, but the latest one adds an extra layer of sophistication. Take the new LT4 engine for example, it is a development from the LT1 of standard Corvette. It has modern features that you wouldn't believe, such as direct injection, variable cam phasing (on its sole camshaft) and Active Fuel Management (i.e. cylinder deactivation) thus fuel economy is greatly improved. Then it is enhanced with stronger cylinder heads, titanium intake valves, forged pistons, machined con-rods, stainless steel exhaust headers and dry-sump lubrication. Inside the V-valley is filled with an Eaton R1740 TVS supercharger. Its smaller and shorter rotors pump out 1740 c.c. of air every revolution, smaller than the 2300 c.c. on the late ZR1, but by raising its maximum rev from 15,000 to 20,000 rpm, the amount of airflow is actually the same. Of course, the smaller rotors enable quicker response and waste less energy on friction at light load. The higher, 10.0:1 compression ratio enabled by direct injection also enhances torque output at low revs. The supercharger and its integrated intercooler add just 25 mm height above the engine.

Predictably, the car has a power dome on the bonnet to accommodate the taller engine. It incorporates ventilation lourvers to release hot air from the engine compartment and contribute to downforce. Speaking of aerodynamics, the Z06 looks almost like a race car, especially with the Z07 track package. Its front splitter protrudes aggressively from the air dam and incorporates vertical winglets at either side. This is matched with massive side skirts. Brake cooling ducts are opened on the front mesh grille as well as just before the rear wheels. Larger side vents are opened behind the front wheels. At the back, the track package adds a larger tail spoiler whose center section is see-through (mind you, top speed drops to 186 mph with this package). The aero kits are all made of carbon-fiber.



The mostly glass-fiber body work is supplemented with carbon-fiber bonnet and roof. To accommodate the massive, 285/30ZR19 and 335/25ZR20 Michelin Pilot Super Sport rubbers, the front and rear fenders have been widened by 56 mm and 80 mm respectively. The aluminum chassis of C7 is already very stiff, so modification is limited to a carbon-fiber torque tube. Compared with the old Z06, its rigidity is upped by a massive 60 percent. This provides a solid foundation for the double-wishbone suspensions, which accept sportier calibration than the standard Corvette, of course. The magnetic adaptive dampers of C7 are another significant upgrade in the view of control and ride quality.

The rear-mounted transmission is either the Stingray's 7-speed manual with rev-matching capability or a new GM 8-speed automatic. It might sound odd for such a track-oriented car to opt for a torque-converter auto, but GM claims its upshift under wide open throttle is faster than the PDK box of Porsche 911 Turbo. Moreover, with the help of launch control it can out-accelerate the 7-speed manual from 0-60 mph. The Stingray's optional electronic-controlled LSD is made standard on the Z06 to deal with the extra power and contain oversteer.

Nevertheless, all these sophistications add weight. The Z06 weighs just over 1600 kg, not as much as a Nissan GT-R, but it is 83 kg heavier than the old ZR1. This explains why most American magazines failed to improve on the previous straight line performance figures. Besides, the new car with its downforce-oriented aerodynamics fails to match the old car's 205 mph top speed. No wonder GM refuses to badge it as ZR1.

However, with Z07 package equipped, the new car is unquestionably faster on a race track. This package adds not only downforce but also Brembo carbon-ceramic brakes, 35-percent stiffer suspension and semi-slick Michelin Pilot Sport Cup 2 rubbers. On dry surfaces, it could generate an astonishing 1.2 g of grip! Such an unshakable roadholding is perhaps the most impressive aspect of the Z06.




On the road, the new Z06 is bit unexpected. You might expect the driving experience to be dominated by the supercharged V8. Yes, it is very powerful. It produces mountains of torque as soon as you floor down the gas pedal. Its sonorous soundtrack is quite addictive, too, with no traces of supercharger whine. However, the new engine feels no more special than that of the last ZR1. It is just as good as expected for its kind. If you chase for the last word of excitement, a high-revving V10 or V12 would be a better bet. In contrast, the 7-speed manual is surprisingly refined. Its clutch take-up is smooth and linear considering the amount of torque it has to deal with. Its gearchange is no longer clunky. The rev-matching function speeds up the gearchange and makes it far more engaging. It is so satisfying to use that you can easily forget the performance edge of the alternative 8-speed auto.

Another surprise is the chassis. Apart from strong roadholding, it is quite well balanced, unlike the old ZR1 which had its chassis easily overwhelmed by its tremendous power. Thanks to the improved static balance (now 50:50 instead of 52:48), stiffer chassis and active differential, the new Z06 puts down power more efficiently, contains wheel spin and slide a lot better and steers more accurately. As a result, you can push it much harder in fast bends. For a conventional front-engined rear-drive sports car, its handling is remarkable, if outstanding is reserved for Ferrari F12 or Aston Martin V12 Vantage S. Of course, mid or rear-engine cars like 911s or 458 can always find more traction and sharper steering. The Z06' Cup 2 rear rubbers are massive and super-sticky, but they have less weight to act on and far more torque to deal with. This means, if you are hard on throttle in corner exit, it will still slide more easily than most European rivals. Moreover, once it has exceeded the limit of adhesion, it breaks away more abruptly than those cars. Admittedly, you do need to push really hard to see the tricky side of its handling. On public roads, you will be just shocked by its strong roadholding and the stopping power of its ceramic brakes.

The Corvette’s steering is quite good for an electric-assisted rack, if not ultimately as good as those of Porsche GT3, Aston Martin or Ferrari. You can also criticize its relatively low-rent interior or creaks of its plastic body panels. However, for the price it asks and the performance it delivers, these compromises are understandable. Moreover, this car serves remarkably well as a daily companion, offering good ride quality, all kinds of creature comforts, a removable roof and a big boot. A mid-engined super Corvette will make better use of the tremendous power, but right now, the Z06 is the King of Corvette as well as American sports cars.
Verdict:
 Published on 20 Oct 2016
All rights reserved. 
Corvette Grand Sport


Basically, Grand Sport is the track-oriented version of Corvette. It keeps the standard car’s 460-hp V8, which is a slight disappointment considering what Porsche has done to the engine of GT3 RS. Instead of powertrain, work was concentrated on aero, suspension, brakes and tires. The Corvette line is already served with a large pool of performance options. Grand Sport makes use of them to improve its handling. These include the standard fitment of electronic LSD, magnetic ride adaptive dampers, larger Brembo brakes and a set of wider tires coming from the mighty Z06, i.e. 285/30ZR19 up front and 335/25ZR20 at the rear. These rubbers look oversized for the power they have to handle, but they do enable the car to corner at 1.05g. To accommodate them, the Grand Sport needs the flared wheel arches of Z06, so it looks pretty aggressive.

If you buy a Grand Sport, you would be foolish to forgo the optional Z07 package, as it adds carbon-ceramic brakes and stickier Michelin PS Cup 2 tires (instead of PSS). The powerful brakes shorten stopping distance considerably yet they never fade. However, the shortlived, track-oriented tires have even more influence to performance, because they lift the lateral grip to an eye-popping 1.18g, making the car corner significantly faster, resisting understeer and oversteer as if running on rails. They also improve rear-end traction hence standing-start acceleration slightly. On the downside, like all track tires, they need heat and a dry surface to build up adhesion. On a cold or wet day, the rear tires struggle to put down the power thus you have to turn up the traction management to avoid spin or sideway.

Another must-have option is the stage-2 aero kits, which is the middle choice on Z06. It slows the car’s terminal speed to 175 mph but produces the downforce necessary to keep the car stable in fast corners.

The Grand Sport is not cheap. It starts at $66K, $10K more than a Stingray. With the aforementioned options it is already $77K. When fully optioned it costs nearly as much as a Z06, which offers a lot more power and drama. If you rarely visit tracks, it would be meaningless to buy a Grand Sport, because on public roads you don't have the speed and space to access its deep reserves of grip. Yes, it doesn't sacrifice much in ride or creature comfort, thanks to the magnetic dampers and feature-rich cabin, but it doesn't show any advantages over the standard Corvette either.

As a track-oriented special, it still lacks a couple of things to impress. Firstly, more power and an angrier engine noise could have given it a distinctive character. Secondly, a thorough weight reduction could have made it feel more agile and faster still, not just all about roadholding. As it doesn't have both, it fails to repeat the magic of Porsche 911 GT3 RS. In short, it
needs more Renn and less Grand.
Verdict:
Specifications





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission

Suspension layout
Suspension features
Tires

Kerb weight
Top speed
0-60 mph (sec)

0-100 mph (sec)

Corvette
2013
Front-engined, RWD
Aluminum frames
Glass-fiber, carbon-fiber
4495 / 1877 / 1235 mm
2710 mm
V8, 90-degree
6162 cc
OHV 16 valves, VVT
-
DI, cylinder deactivation
460 hp / 6000 rpm
465 lbft / 4600 rpm
7-speed manual

All double-wishbones
Adaptive damping
F: 245/35ZR19
R: 285/30ZR20
1562 kg
190 mph (est)
4.0* / 4.3**** / 4.4*****

9.2* / 9.5**** / 9.4*****

Corvette Z06
2014
Front-engined, RWD
Aluminum frames
Glass-fiber, carbon-fiber
4495 / 1960 / 1235 mm
2710 mm
V8, 90-degree
6162 cc
OHV 16 valves, VVT
Supercharger
DI, cylinder deactivation
650 hp / 6400 rpm
650 lbft / 3600 rpm
7-speed manual or
8-speed automatic
All double-wishbones
Adaptive damping
F: 285/30ZR19
R: 335/25ZR20
7M: 1602 kg / 8A: 1606 kg
195 mph (186 with aero kits)
7M: 3.3* / 3.3** / 3.3***
8A: 3.0*
7M: 7.5* / 7.4** / 7.6***
8A: 6.8*
Corvette Grand Sport
2016
Front-engined, RWD
Aluminum frames
Glass-fiber, carbon-fiber
4520 / 1965 / 1235 mm
2710 mm
V8, 90-degree
6162 cc
OHV 16 valves, VVT
-
DI, cylinder deactivation
460 hp / 6000 rpm
465 lbft / 4600 rpm
7-speed manual

All double-wishbones
Adaptive damping
F: 285/30ZR19
R: 335/25ZR20
1565 kg
175 mph (est)
3.8* / 3.9** / 3.7***

8.7* / 8.8** / 8.5***





Performance tested by: *C&D, **MT, ***R&T, ****Sport Auto, *****Autocar





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General models


Grand Sport


Z06



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