The new 650bhp Chevrolet Corvette Z06 is a classic case of giving the customer what they want.
As well as being the most powerful model in the iconic American sports car's long history, it is also a direct reflection of existing Z06 customers' demands for more variations, according to Corvette chief engineer Tadge Juechter.
In addition to the Z06 hard-top, with its removable roof panel, there is now a convertible version. Both hard-top and soft-top can also be fitted with either a manual an automatic transmission, a first for the Z06.
Save for the pushrods and the dry-sump lubrication, this supercharged 6.2-litre LT4 Chevy small-block is filled with modern technology. It starts in similar form to the standard Stingray LT1 V8, with an aluminium block and cylinder heads, but adds forged connecting rods and pistons, and those pistons are re-engineered for this engine's 10:1 compression ratio.
Direct injection, variable valve timing and cylinder deactivation are part of the package, and the engine's pushrod design allows for the intercooled supercharger to be placed in the valley between the cylinder heads. In all, the supercharger adds just an inch to the engine’s overall height, maintaining the Corvette’s exceptionally low bonnet line.
While the previous-generation Corvette ZR1 was also supercharged, this new Z06's supercharger is entirely new. It spins faster (20,000rpm, compared with 15,000rpm in the ZR1) and has smaller screws and improved airflow management.
At a reasonable 1600kg, the Z06’s acceleration permitted by its 650bhp fully shoves you into your seat with uncompromising force. Starting in first gear, you’re thrust against the seatback and don’t get any relief until the middle of fourth, and by that time you’re doing well over 120mph.
Transmission options are the familiar seven-speed manual, with a Z06-specific lightweight clutch and flywheel assembly, or an all-new eight-speed automatic.
Some may say the only type of automated transmission suited to performance cars is a dual-clutch unit, but Chevrolet has raised the bar for the torque converter transmission. With full-throttle shifts a tick quicker than a Porsche 911's PDK (0.08sec, according to Corvette engineers), the auto is still a smooth-shifting slushbox when you're commuting in traffic.
An auto-equipped Z06 is ultimately quicker around a given circuit, but the manual is decidedly more satisfying to drive. The gates are defined so that on-track misshifts are only for those with the least deft hands, and the heft of the shifter complements the rest of the controls.
One oddity in the manual car is the leftover shift paddles on the steering wheel. Perhaps intended for the automatic car and only retained to reduce tooling costs, their function with the manual is to engage the active rev-matching system, which is meant to save drivers from the footwork required for smooth heel-and-toe downshifts.
An electronically controlled limited-slip differential is standard on the Z06, and its hydraulically adjustable clutch splits power, from full open to fully engaged, in fractions of a second based on an algorithm using a range of inputs from systems throughout the car.
Further, the e-diff is tied into the other systems in the Z06 and varies its action based on the wide range of drive mode permutations. Under braking, for example, the differential is fully open, making the Corvette exceptionally stable while decelerating.
Brakes on the standard Z06 use two-piece rotors on both axles with six-piston front and four-piston aluminum calipers rear, while the optional Z07 package fits a carbon-ceramic system with massive rotors, incidentally shaving 10.4kg in total. Both systems are supplied by Brembo and are remarkably effective at deleting speed, particularly on track and especially on the technical and braking-biased Spring Mountain circuit in Nevada.
Available to the driver is a range of drive modes - perhaps one or two too many for a supercar like this Z06. From the dial on the console, the driver may select settings for Weather, Eco, Tour, Sport and Track and then further drill down into Track mode for a subset of settings from wet to minimal driver assist.
Cosworth supplies Corvette Racing with the team’s data acquisition and telemetry systems and was tapped to develop the Performance Data Recorder for the road car. Beyond the thrill of a video recording of your laps, it also captures a basic set of data channels for off-track analysis.
The chassis is 20 percent more rigid than the previous hard-top version of the Z06 – with the carbonfibre roof panel removed. With the roof panel in place, Chevrolet says the chassis is 60 percent stiffer than the previous model. The aluminium frame is so robust that both the roadgoing Z06 and the C7.R Le Mans racer use the same basic component, which is produced in house in Bowling Green, Kentucky.
Bespoke Michelin Pilot Super Sport runflat tyres were engineered for the Z06, and compared with the Stingray’s, these Michelins run one and a half inches wider at the front and two inches wider at the rear, necessitating new bodywork.
The front wings have been widened by 56mm and the rears by a massive 80mm, giving this Corvette a total width of nearly two metres. The new bodywork enhances the existing Stingray aerodynamics with additional downforce and improved airflow for cooling, braking and the supercharger’s integrated intercooler.
A head-up display is standard equipment on the upper trims and features a useful bar graph tachometer and G-meter when using the Z06’s track mode. The Stingray’s base and optional Competition seats carry over to the Z06, and they’re the best seats fitted to any Corvette.
Comfort and support are quite good for both seats – a radical departure from the sixth generation’s utterly horrible seats - although there is little difference between the two, even under on track g-loads.
The Z07 Performance package includes the aforementioned four-wheel Brembo carbon-ceramic brake package, Michelin Pilot Sport Cup 2 runflat tyres, magnetic adaptive suspension and obvious additional front and rear aero bits, including a clear adjustable rear spoiler. With its height, the view out the rear-view mirror would be compromised if that tall spoiler were opaque, so instead Chevy engineers specified that this one be see-through. Clever.
The cockpit is orientated towards the driver, and the passenger interface to the major systems is entirely a secondary consideration. Materials range from quality leathers to hard, budget plastics that aren’t suited to any car costing over £50,000, let alone £90,000. Even the rear bumper cover flexes and squeaks like a plastic cup. But the equipment list is fairly comprehensive, with keyless entry and start, a 360-degree camera system, cruise control, heated and ventilated seats and dual-zone climate control all fitted as standard. Dominating the dashboard is Chevrolet's 8.0in touchscreen infotainment system complete with sat nav, Bluetooth, smartphone integration, DAB radio, a Bose sound system and GM's Onstar driver assistance and wi-fi package.
As in the Stingray, the steering is electrically assisted, with the best feel and feedback ever found in a Corvette, but it lacks some of the fidelity of a Porsche 911 or an Aston Martin V8 Vantage.
The optional Cup tyres are near race-spec and give the Z06 what is simply an obscene amount of grip: 1.2g, according to our data from the car’s data recorder. Where the Super Sports make this Corvette a willing dance partner and allow you to play with and explore its limits, the Cups feel like an endless wall of grip, but when you exceed the limit, breakaway can be rather abrupt.
The Z06 would be faster over a lap on the Cup tyres, but they make the Z06 the kind of supercar that reserves its greatest rewards for the most courageous and skilled drivers.
Rivals such as Porsche’s 911 Carrera GTS and the Aston V8 Vantage have finely finished interiors and more overall refinement, but the Corvette Z06’s performance numbers exceed those of their maxed-out siblings, the 911 Turbo S and V12 Vantage S.
The Z06 is the kind of bargain that places its legitimate supercar levels of performance above all else, even if it means sacrificing a little fit and finish and some refinement.