Braking hard from 142 mph on the front straight at the Pittsburgh International Race Complex, the 2023 Chevy Corvette Z06‘s 8-speed dual-clutch automatic fires through three downshifts, and the new flat-plane-crank 5.5-liter V-8 responds with an exotic sound befitting the C8 Corvette’s exotic mid-engine design.
Whumm, whumm, whumm!!!
Damn. I feel like a C8.R Corvette race driver, which is convenient because longtime Corvette racer Oliver Gavin is leading the way on these hot laps.
The LT6 V-8 barks much louder than in the LT2 6.2-liter V-8 in Stingray Corvettes, revs far higher, and works beautifully in tandem with the dual-clutch automatic transmission. The LT6 makes 670 hp at 8,400 rpm and 460 lb-ft of torque at 6,300 rpm. It’s the first dual-overhead cam engine in a Corvette since the Lotus-designed LT5 V-8 in the 1990 Corvette ZR-1, and it’s the most powerful naturally aspirated V-8 ever unleashed on the market.
The engine and transmission are at their best on this 19-turn, 2.8-mile track, though there’s also something to be said for the simple bark of the V-8 on startup. The LT6 doesn’t make its best torque until about 3,500 rpm, but it’s big enough to provide good torque down low anyway. Given the opportunity to open it up on the track in a way that would earn me a reckless driving citation on the street, I can feel just how freely the LT6 revs to its sweet spot and on to it 8,500-rpm redline (8,600 rpm is the fuel shut-off point, but by the time the transmission completes the shift at 8,500 revs, the engine is already at 8,600 rpm).
I can choose my own shifts via a pair of magnesium (standard) or carbon-fiber (Z07 package) steering wheel paddles, but the transmission does such a great job of holding the revs and shifting quickly that I see no need to do poorly what the transmission does so well. In Track mode, the car juts forward for a beat after gear changes before settling in to make the quick climb to the next gear.
The DOHC LT6 comes from a brand known for pushrod V-8s. The choice to go with a flat-plane crank was all about efficient breathing. The engine, which features dry sump lubrication and a camshaft in each cylinder head, works much like two 4-cylinders joined by one crank, and the flat-plane design allows the pistons to fire back and forth on the opposite banks. That means the intake pulses are spread out uniformly, and that is one reason the engine can rev so efficiently. In fact, Chevy engine Dustin Gardner says the engine can take in so much air it has 10% greater volumetric efficiency, which he describes as effectively giving it a 10% boost or working like a 10% larger engine, i.e. a 6.0-liter V-8.
Despite bigger heads for the DOHC design, the LT6 weighs only about 2 lb more than the LT2 Stingray engine while delivering 175 hp more. It’s also about 31 lb lighter than the supercharged LT4 V-8 in the last Z06, which made 650 hp. Lighter internals, such as titanium rods and a 30% lighter crank, also team with a short 80 mm stroke (vs 92 mm in the LT2) to help it rev quickly.
A pair of 87 mm throttle bodies, one for each cylinder bank, and direct injection keep up with the fuel needs to match the engine’s efficient breathing. To handle all that power, the Tremec 8-speed dual-clutch transmission gets beefier internals.
The physics from the C8 Stingray are still in effect here: With 60% of the weight over the rear axle due to the mid-engine design, the car hooks up very efficiently and rockets forward to the tune of a 2.6-second 0-60 mph time. Extend that to a quarter-mile and the time passes in 10.6 seconds. Despite the car’s extra power, track-focused aerodynamics limit its top speed to just 1 mph faster than the Corvette Stingray at 195 mph, and that falls slightly to 189 mph with the Carbon Fiber Aero package.
Same platform, different tuning
Chevrolet developed the C8 Corvette from the start with the Z06 in mind, so nothing had to be done to the platform to contend with the extra power and the greater dynamic loads it would enable. The suspension geometry also didn’t change, but changes were necessary to the brakes, suspension tuning, steering, and aerodynamics.
Much of it is built around a bigger set of shoes. The Z06 rides on staggered 275/30R20 front and 345/25R21 rear tires, which are 1.0 inch larger in diameter all around, 30 mm wider up front, and 40 mm wider at the rear.
The wider tires required a wider body and the improved performance dictated improved aerodynamics. The fenders bulge out an extra 3.6 inches at the rear and slightly less up front, the nose gets a front splitter, a front fascia opens up to channel more air to more powerful outboard fans and a new center heat exchanger, and the rear fascia is reworked to accommodate a four-pipe center exhaust. Chevy also adds another rear heat exchanger for even more cooling.
The body also changes for aerodynamics. The standard Z06 comes with rear wickers that the customer can install. Without the wickers, which add about 1.5 inches of spoiler height at the rear, the car is neutral in terms of lift and downforce. With the wickers installed, a pair of stall gurneys at the back of the front underwing (just in front of the front tires) balances the car to create 362 lb of downforce at 186 mph. Opt for the Carbon Aero package, and its big rear wing, front dive planes, and underbody strakes give the car 734 lb of downforce at 186 mph. The rear wing is so effective that it has to be screwed into the rear bumper beam.
Underneath, the Z06 sports 30% stiffer spring rates than the Stingray with the Z51 Performance package, and the Z07 package adds 10% more stiffness. The springs are so stiff that Chevy had to add helper springs to keep them seated during extreme rebound situations. The bushings and standard magnetic shocks are also stiffer, but the anti-roll bars are slightly smaller because the springs provide the roll-rate resistance that would normally be handled by the bars. Chevy also dials in less steering boost off-center with the optional carbon-fiber wheels—which save 41 lb of unsprung weight—to give cars so equipped the same steering feel as cars with the standard forged alloy wheels. For best traction and braking, the cars I’m driving on the track also have a track alignment with an extra degree of negative camber all around (-2 degrees instead of -1), and they’re running a performance brake fluid.
At 13 inches wide, the carbon-fiber wheels are the widest yet made for a street car. They’re available with the Z07 package, which also includes stiffer settings for the magnetic dampers, the Pilot Sport Cup 2 R tires, and Brembo carbon-ceramic brakes that measure 15.7 inches up front and 15.4 inches in the rear. The latter are the biggest brakes ever put on a Corvette, and the base brakes are big, too, at 14.6 inches up front and 15.0 inches in the rear. Both use 6-piston front and 4-piston rear calipers.
Track car for the street
Chevrolet says the goal was to make the Z06 a track car for the street, but also keep it approachable for everyday driving. That will be determined by the eyes, ears, and kidneys of the beholder. On the street, the stiff dampers create a busy ride that can pound over sharp bumps and deep potholes. However, the ride isn’t punishing in Comfort mode, and it’s aided by the seating position, which sets the driver between the axles instead of over the rear axle like the C7 Corvette.
The wide tires are also more likely to tramline along freeway seams, though I didn’t feel any of that during my 50-plus-mile street drive mostly on two-lane roads. I did notice, however, that the front-and-center character of the raspy flat-plane crank V-8 challenged the ease of conversation at times. It also emits some mid-range drone that I could see becoming tiresome during a long drive.
Any negatives on the street are more than offset by the Z06’s track prowess. The standard Michelin Pilot Sport 4 S tires provide lots of grip, but the Z06’s available Michelin Pilot Cup 2 Rs increase that to an astounding 1.22 g of lateral grip on a skidpad. During my time on the track, I see lateral grip and braking measurements of 1.25 g on a handy meter in the instrument cluster.
When attacking corners, the car does what I tell it to. It can understeer slightly if I go too hard into a corner, but the strong brakes (either version) let me get the speed under control easily and the car rotates willingly with more weight on the nose. Similarly, the ready power can cause the tail to wag if I get on the throttle before completing a turn. In either case, the car can go into a short slide that, while easy to catch, can become a problem at the crazy speeds the Corvette Z06 can achieve ever so quickly. I recommend owners who track their car to stick with the Sport setting of the Performance Traction Management system as the Track modes shut off stability control. The safety net lets you play, but it can also catch the car when you mess up.
The steering can feel a tad too light in the Comfort drive mode on the street, but it firms up well in Track mode, feels stable, and reacts quickly to my inputs. It’s a blast to charge hard into a corner, hop on the binders, balance the car with a dab of brake or throttle mid-corner, and chase a five-time American Le Mans Series champion to the next corner—all the while with a glorious a flat-plane crank providing the soundtrack. I can think of precious few better ways to spend a day.
The 2023 Chevrolet Corvette Z06 goes on sale soon with a starting price of $106,395 (including destination) for a “base” 1LZ trim in the coupe body style. Go for the power-hardtop convertible and the price jumps to $113,895. The 2LZ versions add more equipment for $9,200, more and the top 3LZ versions run $120,245 for the coupe and $127,245 for the convertible. To get to the ultimate in performance first requires the $10,495 Carbon Aero package and then costs $8,995 for the Z07 package. Tally it all up, and a Z06 can top $146,000, and that’s before any other options.
It may be pricey, but the Corvette Z06 is an exotic sports car that still undercuts Italian, German, and European rivals in price while delivering just as much or more performance. It’s a loud, hard-charging, hard-riding, high-performance sucker punch of a sports car.
Chevrolet paid for airfare, hotel, and glorious track time for Motor Authority to experience one hell of a day at the racetrack to bring you this firsthand report.
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