What car are we describing? It’s a wedge-shaped, two-seat Chevrolet with a rear transaxle, a front-mounted pushrod 6.2-liter V-8 with an Eaton TVS supercharger nestled in its valley, and some carbon-fiber body pieces. It makes more than 600 horsepower, wears shocks filled with magnetorheological fluid, and is offered with carbon-ceramic brakes nearly as large as those fitted to the Bugatti Veyron 16.4.
If you guessed the dearly departed Corvette ZR1, you are correct. If, however, you guessed the 2015 Corvette Z06, you are also correct. If you guessed anything else, you’re reading the wrong magazine. Because of the upcoming Z06’s striking similarities to the ZR1, we’ve taken to thinking of the new car as the “ZR06.”
Yes, the rip-roaring, high-revving, naturally aspirated, 505-hp 7.0-liter LS7 of the previous Z06 is gone (though it lives on in the upcoming Camaro Z/28). That the new Z06 has a blown engine shouldn’t come as a surprise. We noted about a year ago that the standard Corvette Stingray’s instrument panel includes a digital boost-pressure gauge buried in the driver-information menus. Menus it no doubt shares with the new Z06.
If it helps you get over the loss of the nasty-wonderful LS7 engine, know that Chevrolet is trying to deliver as much output with the Z06’s new LT4 V-8 as it did with the old ZR1. In other words, a staggering 638 horsepower. But because the Z06 won’t go on sale until early next year, Chevrolet hasn’t settled on a final figure. The company estimates, no doubt conservatively, that the dry-sump LT4 will put out about 625 horsepower. Corvette engineering Grand Pooh-Bah Tadge Juechter says: “It is our aspiration to get to ZR1 power levels. If we can get there, we certainly will.”
He cautions, however, that because the LT4 will use a smaller supercharger than the LS9 engine in the ZR1 (1.7 liters-per-revolution versus 2.3), running about 9.5 psi of boost, it’ll be a stretch. But do not be surprised if it comes very, very close. Know, too, that the company promises the new engine will make at least 625 pound-feet of torque, or 21 more than the former king-of-the-hill Corvette.
That supercharger is mounted atop an engine that uses the standard Corvette’s aluminum block. To handle the increased power, the LT4 uses forged pistons; strong-er, custom-machined steel connecting rods; and titanium intake valves fitted to cylinder heads that are rotocast of A356T6 aluminum for greater strength and heat resistance. It runs a 10.0:1 compression ratio, relatively high for a supercharged engine, thanks in part to the direct-injection system shared with the Stingray’s V-8. The LT4 also uses the same variable-valve-timing and cylinder-deactivation systems as the Stingray’s LT1.