Behind the wheel of the most technically advanced Corvette on the market

Behind the wheel of the most technically advanced Corvette on the market

The Corvette has always been a vehicle whose character is defined by the exact specifications of the particular car in question. It has a long history of employing fire-breathing big block V8s or supercharged V8s with track-ready suspension—but some cars have relied on sluggish base engines and slushy automatic transmissions.

The Z06 performance version of the Corvette is the track-ready iteration of the car, but even within “Z06” there is that same spectrum of potential, a microcosm of the Corvette line itself.

So, even discussing the Z06 requires specificity: We track-tested the top-of-the-line 2023 Z06 that was equipped with all the additional optional go-fast (and stop-fast) equipment because it represents the pinnacle of Chevy’s know-how and the most technically advanced Corvette customers can buy.

Here’s what makes it go, and what it’s like to drive. 

Behind the wheel of the most technically advanced Corvette on the market
The Corvette Z06’s engine. GM

The engine is the star of the show

The main ingredient that distinguishes a Z06 from the Stingray that came out in 2020 is the engine. For the uninitiated, Stingray is Chevy’s new name for the base Corvette. The term goes back to the company’s 1960s concept versions of the Corvettes then in development and some of the subsequent “C2” second-generation cars.

More recently, Chevrolet has formalized a hierarchy of other nomenclature dredged from Corvette’s illustrious history, starting with Z06, which was a high-performance option package in 1963, and topped by ZR1, which was a high-performance model that used an advanced Lotus-designed double-overhead cam V8 engine for the C4 fourth-generation model in the 1990s.

In recent years, Chevrolet has followed a cadence of introducing first the base car—in this case the Stingray—followed at some interval by the Z06 and then ZR1 to maintain interest in the vehicle over the model generation’s lifespan. The company is mum about the ZR1, but the rumor mill says it will use a turbocharged version of the Z06’s engine and an electric motor to drive the front axle. Time will tell.

The Stingray employs the latest 6.2-liter iteration of the famous small block Chevy V8 that debuted in the Corvette in 1955. That means that it has two pushrod-actuated valves per cylinder. This engine has been developed to an astonishing degree to produce 490 horsepower (495 hp with the optional high-performance exhaust).

Small block V8s are compact, efficient, have a low center of gravity, and are inexpensive to build compared to other comparably powerful engines. With this engine, the Stingray is thrilling to drive and is accompanied by the familiar American V8 rumble many drivers want from their Corvette.

Forget all of that for the Z06. It uses an advanced 5.5-liter double-overhead cam design (code named LT6) and employs a flat-plane crankshaft like a race car or a Ferrari. This is because the team wanted to top the previous-generation Corvette Z06’s 650-hp supercharged engine with a naturally aspirated powerplant, because of the more engaging driving experience delivered by engines without forced induction. 

Speaking of forced induction, supercharged engines use a belt-driven turbine to pack air into the engine’s intake tract to make more power. They produce a characteristic whine that builds with rpm as the turbines spin correspondingly faster. Meanwhile, turbocharged engines use compressors for the intake charge that are driven by turbines in the exhaust stream, which makes the boost they provide sensitive to engine speed. When there is a delay in delivering boost, this is known as “turbo lag,” making the power delivery potentially challenging for drivers to manage, as it is not linear. Those exhaust impellers impede the flow of sound from the engine, lending turbocharged engines a slightly muted exhaust note. 

In either case, supercharged or turbocharged, the often-overlook intake sound of a naturally aspirated engine is muffled by the forced induction system, which also dilutes some of the experience of operating a car with an exciting engine.

Internal combustion engines are an endangered species, and naturally aspirated internal combustion engines like this one in the Z06 are on the leading edge of that expected extinction, but Corvette executive chief engineer Tadge Juechter says he wanted America’s Sports Car to give combustion power a glorious send-off.

This engine uses a flat-plane crankshaft, which attaches the connecting rods 180 degrees apart in the engine’s rotation. This creates favorable sequencing of intake and exhaust pressure waves for high-rpm breathing, but it also creates significantly more vibration and a higher-pitched shriek than the familiar 90-degree crankshafts that produce the familiar mellow V8 rumble. 

“With natural aspiration, if you want to make power, you’ve got to spin it!” declares chief engineer Josh Holder. And the Z06 sure does spin, with an 8,600-rpm redline. Peak power of 670 hp occurs at 8,400 rpm.

The flat plane crank, which is 33 percent lighter than the small block’s cross-plane crankshaft, unlocks the ability for the engine to spin that fast, but doing some comes at the cost of vibration. “They’re paint shakers,” Holder says. “Anything that couldn’t withstand that vibration was isolated from the engine.”

The engineering team also minimized the vibration at its source, giving the engine a short-stroke design and short, lightweight titanium Pankl connecting rods to minimize the reciprocation. 

The cylinder heads get special treatment so they can whisk the air into the combustion chambers quickly and then expel it efficiently following combustion. Their combustion chambers are machined and then laser-scanned to confirm accuracy. The eight individual intake trumpets are uniquely designed for the specific cylinder they serve and are polished so their downdraft whooshes past the intake valves, directly into the combustion chamber.

That’s great for redline racetrack running, but some turbulence in the incoming air/fuel mixture encourages mixing to create a homogeneous charge in the combustion chamber. Rather than impeding the flow to induce swirl as the air comes in, Chevy engineers borrowed a trick from the company’s IndyCar program and relocated the direct fuel injectors to the edge of the combustion chamber beyond the exhaust valves so that they spray into the chamber from an angle to help stir things up.

Because the pressure waves in the intake and exhaust systems determine the effectiveness of the design, the Z06’s engine has three large butterfly valves in the bulkhead that divides the intake plenum chamber into left and right halves for each bank of the V8. Two of the butterflies are linked and move together, while the third one opens independently. These valves change positions five times during the engine’s pull to redline, ensuring that the torque curve stays steady, with none of the dips that would otherwise occur.

The exhaust system also contains valves that open to let the departing gasses bypass the mufflers for more power. Unlike the previous system, these are not digital, with just open and closed positions. Instead, they can move progressively, letting more or less air flow through as determined by the car’s drive mode and the throttle position.

Having all of this technology to give Z06 drivers the naturally aspirated driving expense serves little purpose if they can’t hear the difference between this engine and one of its turbocharged competitors, so the team designed the fit of the exhaust pipe tips in the bezels passing through the rear bumper fascia to maximum sound reflected back into the cabin in the frequencies that are pleasing to hear.

Despite the heap of new tech on the Z06’s all-new engine, this powerplant weighs only 2 pounds more than the engine in the Stingray (code-named LT2), while producing an additional 175 hp. Compared to the supercharged LT4 engine in the previous-generation Z06, the new engine weighs more than 30 pounds less and it produces 20 more horsepower.

The engine sends power through the same basic paddle-shifted dual-clutch transaxle as the Stingray, but the Z06’s enjoys a stronger 6-plate clutch, enlarged output shafts, reinforced case and bellhousing, and an additional 2 liters of gear oil inside.

Meet the supporting cast

This, however, is just the beginning, as now the Z06 buyer is faced with a menu of options that can unleash the full potential of the drivetrain. The confusingly named “Z07” option package brings larger Brembo carbon ceramic brake rotors and six-piston front/four-piston rear calipers for the ability to run through an entire tank of fuel on the race track without complaint from the brakes.

The Z07 suspension includes springs that are 10 percent stiffer than those on the base car and magnetorheological dampers that are tuned accordingly. This latest generation of those shocks features a greater range of adjustment authority and faster reaction times to make changes, Holder reports.

The base car rolls on Michelin Pilot Sport 4S tires similar to those used on the Stingray. As on that version of the Corvette, these tires are excellent street sports car tires with admirable durability and the ability to adapt to a wide range of driving conditions. They are, however, not track tires. So the Z07 package comes instead with Michelin Pilot Sport Cup 2R tires like the ones that have impressed previously on the Porsche 911 GT3 RS and the Ferrari Pista.

The optional upgrade with the most shocking contribution to the Z06’s track potential is the selection of the Carbon Revolution carbon fiber wheels. They cost either $10,000 for a black paint finish or $12,000 for a clear finish that highlights the wheels’ carbon weave. In either case, these wheels slash 41 pounds of weight compared to the standard aluminum wheels.

This mass comes out of the Z06’s unsprung weight, which means that there is less mass in the suspension for the springs and shocks to control as the car tracks over surface changes. And it comes from the rotational inertia of the driveline, helping the car accelerate more responsively because there’s less mass to spin.

The result is that these wheels alone, with all other factors remaining the same, contribute to 1.5-second faster lap times around a track that takes two minutes to lap. That 1.25 percent improvement probably sounds small to the lay person, but racers and track rats would probably trade nearly anything for that advantage in a race.

The Z07 package also brings aerodynamic upgrades. The base car is designed to produce 362 pounds of downforce at 300 kilometers per hour (186 mph) and the Z07 add-ons double that to 734 pounds. Downforce is critical to traction in high-speed turns and it is also important for stability on straights. So the 2023 C8 Z06’s massive downforce is a comforting feature.

And finally, the performance 

Blasting out the pit lane onto the track at Pittsburgh International Raceway, the Z06 surges forward on a wave of glorious sound from the unmuffled exhaust. No worries, the bad-weather driving mode gives you the ability to hush the LT6’s voice for those early-morning departures.

The steering wheel-mounted shift paddles provide the opportunity to select gears manually, but you will not be able to do a better job timing shifts than the car’s computer. It will even give the Z06’s flat-plane powerplant a stab of throttle on downshifts to let it announce that it is doing important work here, just as you’d do if you had a conventional shifter with a clutch pedal.

The difference is that the computer will grease the dual-clutch transaxle downshifts with smooth perfection every time, so you don’t upset the car’s balance entering a turn with a rough shift, or worse, over-rev the engine by engaging a low gear too soon.

Mid-corner throttle modulation is easily managed, as the Michelins claw for grip to turn the car and begin the acceleration toward corner exit. Previous experience with the Pilot Sport Cup 2Rs has come with ambient temperatures 25 or 30 degrees warmer than the 55 degrees of the Z06 test. 

Maybe this provided an even better chance to evaluate the ease with which the driver and/or the stability control and traction control systems (depending on the driving mode) can manage the Z06’s corner exit. The engine revs incredibly quickly and the lightweight carbon fiber wheels provide the least possible intrusion on that as the Z06 squirms toward the approaching straightaway, carving an arc to the track’s edge on the way out of the turn.

Down the straight, the Z06 is in its element because this is where the engine is able to pull to redline with wide-open throttle, providing the aural accompaniment that led Chevy to specify a naturally aspirated engine for the Z06 instead of one with forced induction.

And some very good news is that, upon reaching the end of the straight, with the ‘Vette carrying eye-opening speed, the impressive Brembo carbon ceramic brakes deliver flawless deceleration through the brake zone into the turn and they repeat that performance identically lap after lap, without degradation due to heat build up.

Lamborghinis tend to have spongy, confidence-sapping brake pedals in this situation. Ferrari’s brakes are usually better on the track, but are grabby in casual street driving. The Corvette’s provide massively powerful consistent stops on the track and draw no notice to themselves in everyday street driving.

On the topic of street driving, the Z06 is as docile and user-friendly as you could hope despite springs that are 35 percent stiffer than those in the Stingray. The difference is not obvious, probably because the magnetically adjustable shock absorbers can still soften as needed for street driving.

One frequent destination for driving the Z06 will be the gas station. The car carries a $3,000 gas guzzler tax for its thirst, which the EPA rates at 12 mpg in city driving and 19 mpg on the highway, with a predicted daily average of 14 mpg.

That $3,000 in tax is a rounding error for a car in this price range, however. The bottom line on our fully loaded test car is $167,205, which includes all the optional goodies. While this is a gigantic number, it is about half the price tag of various Italian exotics that it can beat on the track and match at the valet line. America’s sports car no longer needs an asterisk or apologies. This is as good as super sports cars get.

Take a look at what it’s like to drive it, below.

YouTube video

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