“We broke a lot of dynamometers testing this engine,” explained Jordan Lee, Chevrolet’s chief engineer for small-block engines, before handlers strapped us into the passenger seat of a 2019 Chevrolet Corvette ZR1 for a few laps of Willow Springs International Raceway. It’s understandable, because the engine to which Lee referred is the ultra-Vette’s supercharged LT5 V-8; its 755 horsepower cracked exhaust piping with its heat and decimated flex plates at General Motors’ engine-testing facility. It’s a common problem among blown V-8s making this much power, it seems—Dodge faced similar challenges developing the 840-hp supercharged Hemi V-8 for its Challenger Demon.
GM eventually added water cooling to the dynos’ exhaust ducting and beefed up the hardware to handle the LT5’s might consistently. After the engine punted us around Willow Springs’ Big Willow, we wished our own bodies could be so upgraded. This fast, undulating circuit is the perfect playground for highlighting the LT5 and the ZR1’s available aerodynamic enhancements, the key upgrades over the 650-hp Corvette Z06 that take it to new performance heights.
The two ZR1 development coupes that Chevrolet had on hand (the convertible version bowed at the Los Angeles auto show earlier in the week) each wore mismatched camouflage and unpainted panels but, critically, were nearly final production spec and equipped with the eight-speed automatic transmission and the ZTK Performance package. This kit adds a towering, adjustable carbon-fiber rear wing and extra vertical fins at each end of the front splitter. It’s no poseur piece: the rear wing’s mounts stab through the Corvette’s bodywork and bolt directly to the frame. ZR1s wear their own bodywork forward of the A-pillar with additional openings to feed the four additional radiators relative to the Z06, as well as half-inch-wider front wheels.
Naturally, the LT5 steals the show. An evolution of the LT4 that powers the Z06, the LT5 has a strengthened crankshaft and wears a larger-displacement Eaton supercharger that juts 2.9 inches higher than the LT4’s flat-topped, low-profile unit. It’s literally too tall for the ZR1’s hood, which is why that panel features a hole in the middle that the LT5 sticks out of. Chevrolet dresses the supercharger in a pretty carbon-fiber cover for added effect. The supercharger pulley is larger than the LT4’s and thus spins the blower at a lower speed, although Corvette chief engineer Tadge Juechter reminded us that fitting a smaller pulley and upping the blower’s speeds “will invalidate the warranty.” The LT5 makes 755 horsepower and 715 lb-ft of torque, gains of 105 horsepower and 65 lb-ft above the Z06’s LT4. Do you really need more?
Leaving the pits for our trio of ride-along laps, Chevy development engineer Alex MacDonald offered a demonstration of the LT5’s power by matting the throttle. Or he just wanted to take a rip. Either way, the ZR1 shoots out of the hole with ferocity, particularly for a car lacking all-wheel-drive traction. Chevrolet says this Vette should reach 60 mph in less than three seconds and lay down sub-11.0-second quarter-mile times. We’d say that sounds entirely plausible. With MacDonald standing on it and guiding the ZR1 onto Willow’s straightaway, our stomach dynos—mercifully not broken by the LT5—perform a gut flip that will be familiar to those who have experienced launching the high-po Tesla Model S variants in Ludicrous mode. The numbers to go with that sensation will come out when we’re able to test the production car ourselves.
Seconds after his launch, MacDonald stands on the brakes to set up for Turn 1, and we ragdoll against the seatbelt. Braking isn’t an area in which the Z06 needs improvement, particularly when it’s equipped with the carbon-ceramic rotors that come standard on the ZR1, and the only difference between the ZR1’s brakes and the Z06’s is a special pad compound. Chevrolet described the difference between them and the Z06’s as similar to that between a stock pad and an aftermarket track-specific item.
Willow’s steep uphill Turns 3 and 4 are more or less flattened by the LT5’s power, and the ZR1 drifts slightly exiting 4 and heading for Turn 5. Turns 6 and 7 are gentler esses that MacDonald essentially straightlines, accelerating to about 140 mph before dabbing the brakes and sailing around the long, sweeping Turn 8 at nearly 130 mph without stepping completely off the throttle. This corner best shows off the ZR1’s advantage over the Z06: downforce. Thanks to the ZTK kit’s giant rear wing, the ZR1 simply squats on its rear tires and feels dead stable in high-speed bends. Diving under 100 mph for Turn 9, we’re kissing 150 mph by the end of the straightaway after crossing Willow’s start/finish line, as you can see in the clip of our hot lap embedded below (shot using a combination of the ZR1’s standard Performance Data Recorder plus a GoPro).
Having not been behind the wheel ourselves, we can’t speak to the ZR1’s chassis balance or turn-in relative to the Z06’s. We can say the car feels more “more” than a Z06 and absolutely violent on track, its braking, grip, and acceleration capable of rearranging your organs like God Himself playing Operation within your torso. At no time, however, did the ZR1 feel snappy or twitchy, even in slower corners where the rear wing isn’t producing anywhere near the 950 pounds of downforce it generates at the ZR1’s top speed.
As if most sane people wouldn’t, MacDonald suggests keeping the Corvette’s multi-setting Performance Traction Management (PTM) system on, reiterating what Chevrolet engineers have told us since the seventh-generation Corvette made its debut in 2014: The car is faster on track with PTM active. For our lap, the car was in PTM’s fairly permissive level four, which meant we experienced the occasional graceful and controlled drift.
So what’s next? Us driving the ZR1, of course, where we can glean more about how the production version behaves in the real world and, eventually, on a racetrack in our annual Lightning Lap track test. Based on this limited experience, the ZR1 is without question the front-engined Corvette’s performance zenith, a fitting hurrah before the mid-engined C8 generation arrives next year. That a few dynos needed to bite the dust for it to happen seems like a fair trade. In fact, we hear that GM ponied up big bucks for even more heat-resistant dyno exhaust plumbing made from Inconel. We take that to mean more power may be on the horizon for future versions of America’s sports car.
VEHICLE TYPE: front-engine, rear-wheel-drive, 2-passenger, 2-door targa or convertible
BASE PRICES: Targa, $119,995;
ENGINE TYPE: supercharged and intercooled pushrod 16-valve V-8, aluminum block and heads, port and direct fuel injection
Displacement: 376 cu in, 6162 cc
Power: 755 hp @ 6400 rpm
Torque: 715 lb-ft @ 3600 rpm
TRANSMISSIONS: 7-speed manual, 8-speed automatic with manual shifting mode
Wheelbase: 106.7 in
Length: 179.8 in
Width: 77.4 in Height: 48.5–48.7 in
Passenger volume: 52 cu ft
Cargo volume: 10–15 cu ft
Curb weight (C/D est): 3600–3750 lb
PERFORMANCE (C/D EST):
Zero to 60 mph: 2.9–3.3 sec
Zero to 100 mph: 6.6–7.4 sec
Standing ¼-mile: 10.9–11.4 sec
Top speed: 211 mph
EPA FUEL ECONOMY (C/D EST):
combined/city/highway: 15–17/12–14/21–22 mpg