August 2018 Issue #20 August 2018 Issue #20 | Page 30

CAR
2019 CORVETTE ZR1
This is it. The zenith. The top dog. The 755-horsepower ne plus ultra Chevrolet Corvette C7.
The most powerful and likely the last variant of the front-engine Corvette.
While waiting for the arrival of the mid-engine C8 somewhere in the not-distant future, for the
2019 model year, there are now 28 iterations of the seventh-generation Corvette (C7), including
coupe/convertible versions of Stingray, Grand Sport, Z06, and now the ZR1. Is this as good as it
gets? Is the ZR1 the greatest Corvette ever?
LT5 > LT4
Let’s start with what makes the ZR1 the ZR1, namely its mighty LT5 motor. If you like compar-
isons, this C7 ZR1’s supercharged V-8 makes more than double the horsepower of the V-8 in
the 1990 C3 ZR1 and 117 more horsepower than the C6 ZR1. Based on the venerable LT4
found in the Corvette Z06, Camaro ZL1, and Cadillac CTS-V, the 6.2-liter LT5 features a new
95mm throttle body, both port- and direct-injection fuel delivery, an upgraded crankshaft, a new
oiling system, and a new Eaton supercharger. At 2.6 liters, the supercharger is 52 percent larg-
er than the LT4’s, yet cruising at 80 mph, it draws only 1 horsepower while providing virtually
no boost. On the other hand, it needs 110 horsepower to spin its roots-type helix rotors up to
15,860 rpm to make peak boost pressure of 13.96 psi near redline. The LT5’s intercooler has
roughly double the heat exchange capacity of the LT4’s, and there are four new heat exchang-
ers (13 “radiators” in total) tucked hither and thither. Combining all of this with the new “halo”
hood, the ZR1 boasts 41 percent more air flow than the Z06, which is notoriously prone to pow-
er-sapping engine-protection mode due to excess heat. Rest assured, Corvette “Jake” fans, the
two ZR1s we had showed no problems with heat during our instrumented testing (eight consec-
utive quarter-mile passes followed by a dozen laps of our figure-eight course). Nor did either
lose power with hot laps (two sets of three each) at Willow Springs Raceway, where we’ve pre-
viously documented issues.
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