EV-olutionary Process

How Genovation transformed an ordinary C7 into the all-electric GXE hypercar

Photo: EV-olutionary Process 1
December 24, 2020

Stunningly swift. Eerily quiet. And slightly sacrilegious—at least to some Corvette traditionalists. Those attributes and more apply to Genovation’s GXE, an all-electric version of a 2018 C7.

But for automotive Luddites rankled by the mere mention of a battery-powered Corvette, it’s time to face facts: Electric vehicles (EVs) are now firmly embedded in the automotive landscape, with a record number of almost 100 pure-electric EV models (as opposed to gas-electric hybrids) set to debut by the end of 2024. So convention be damned.

Moreover, a properly engineered EV isn’t some sort of glorified golf cart—it can be a hypersonic performance machine. As evidence, consider the impressive speed capabilities of EV dragsters and Formula E racers, along with the spate of electric supercars now on the market.

Note, too, that during the GXE’s development back in 2017, a prototype, C6 Z06–bodied Genovation test car notched a world record of 209 mph on the expansive runway used for landing NASA’s Space Shuttle orbiters.

Photo: EV-olutionary Process 2

Virtually every nook and cranny of the GXE’s body appears to be crammed with batteries, motors, inverters, or cooling equipment. At least charging “fill-ups” can still be accomplished via the factory fuel port.

As if that isn’t proof enough, the C7 version of the GXE broke the track record for street-legal EVs at Thunderhill in Northern California, with pro racer Randy Pobst manning the wheel. His unofficial lap time, as measured by GPS, was 1:21.16. This figure was just a hair behind the top two runners, a Lamborghini Huracan Evo (1:20.00) and McLaren 600LT (1:20.42), but it bettered the track time of a 2020 Stingray (1:22.83).

Given the heady dose of torque delivered by the powertrain, Pobst feels the car is capable of even quicker times, despite weighing some 500 pounds more than a stock C7. Also, Genovation CEO Andrew Saul feels this prototype can be pared down from 4,600 to 4,200 pounds on the production car by using carbon-fiber battery enclosures and brackets instead of aluminum.

We experienced only a tantalizingly brief—and exhilarating—drive in the GXE, but veteran wheelman Pobst speaks with far more authority on the car’s handling and acceleration, having driven dozens of laps over a two-day period. One obvious question, considering the car’s different dynamics and instantaneous torque, is how he had to change his driving technique in the corners.

“I love torque,” Pobst says. “I’ve never driven a car with too much. Since the GXE is heavier than a Corvette, the inputs have to be more gentle. With more weight, you’re dealing with more momentum.”

Photo: EV-olutionary Process 3

Based on his years of competition, with 90-plus wins to his credit, Pobst points out that in a really light car, “You can just throw it around.” In contrast with the heftier GXE, “You have to baby it—treat it kinder, gentler.

“Of course you can slam it down and do a hell of a burnout in First or Second gear,” he says. “So you have to meter out throttle when you first tip in, and watch the power coming off the corners—it’s a beast! It would make a really good hill-climb car.”

Overall, Pobst found the GXE quite easy to drive. “I think it handles better than a regular Corvette…It’s like driving a silent Corvette with a perfect torque curve. It’s not picky about the gear choice.”

The quietness of the driving experience was not a disadvantage, either, since less noise and vibration means fewer distractions and less driver fatigue. And it was easier for Pobst to hear the pit crew in his headset, too.

Photo: EV-olutionary Process 4

Revised DIC displays data from the car’s myriad sensors.

Before going into detail on the GXE’s powertrain setup, we should note that those V-8–centric readers unaccustomed to EVs will likely encounter some unfamiliar terms. EV technology is steeped in an arcane jargon, and one item in particular might need some brief explanation: the inverter. It’s one of the most critical components under the hood of any EV, since this device converts the batteries’ DC power to the AC power of the motor. But Genovation took things a step further than most other EVs.

“What differentiates us is, our software enables us push the motors and inverter harder,” Saul notes. In addition, the GXE uses two motors (supplied by Cascadia, subsidiary of Borg-Warner) operating through a custom coupler hooked up inline to a single drivetrain. This pair of smaller motors makes for easier packaging than a single big one. Interestingly, the factory torque tube is retained for rigidity.

As for the inverter, also called an AC Drive or VFD (Variable Frequency Drive), it is also responsible for controlling speed and torque for electric motors by varying the frequency of the alternating current. Without an inverter, the motor(s) and battery in any electric drivetrain would be completely incompatible.

How much juice are we talking about here? The setup currently makes 800 horsepower and 718 pound-feet of torque at the rear wheels. (Although in First gear, a test on a dyno chassis clocked well over a 1,000 hp, Saul claims.)

Photo: EV-olutionary Process 5

With 718 lb-ft of rear-wheel torque instantly available, the GXE is a burnout machine nonpareil. Quad rear taillamps are reminiscent of Nissan’s GTR, while the aero under-tray evokes the Corvette Racing C7.R.

What makes an EV so different is that all of this power is on tap immediately. The acceleration feels like releasing a taut slingshot, with utterly no hesitation. Gone is the delay in spinning up the revs of a V-8 and stirring gears to find the heart of the power band. The seamless takeoff of this EV is similar to the experience provided by a steam catapult on an aircraft carrier. According to computer calculations, a quarter-mile time of 10 seconds at 130-plus mph is possible, Saul says.

Getting all that juice to ground, however, required a substantial amount of engineering. Saul admits that pairing the electric motors with the C7’s automatic transmission was more of a challenge than it would have been with a manual gearbox, due to the auto’s higher level of sophistication. “It took a lot of work to trick the transmission controller into believing there was still a V-8 engine up front,” he says. He also points out that maintaining optimum battery temperatures is critical for fast charging, performance, and durability. No surprise, then, that three special cooling systems are needed for the battery system, inverters, and motors, the latter using a non-conductive fluid.

For now, the GXE runs off cylindrical 18650-type batteries, similar to those found in Tesla Model S and X electric vehicles. Since the C7 chassis does not have a flat, “floor pack” architecture, the batteries are placed in a variety of locations, wherever they will fit, such as in driveline tunnel, the space normally used for the fuel tank, and in the trunk area. We happened to get a sneak peek under a panel in the rear, where we spotted a mystifying array of wiring and electronics. In addition, there’s a 12-volt battery to run auxiliary systems such as the audio, lights, door locks, and A/C.

To compensate for the extra 500 pounds of the EV system, the suspension no longer has the factory electromagnetic shocks, but rather stiffer, adjustable DSC units tuned in conjunction with the an active rear wing from Aeromotion. The foil was tested in MIT’s wind tunnel, where it reportedly produced the best downforce-to-drag ratio ever recorded. This aspect proved to be a significant aid, since the roughly 45/55 front/rear weight distribution of the GXE is slightly different from that of the nearly 50/50 C7. Pobst actually prefers the rear bias with more weight over the rear wheels. “I want the load on the back,” he says.

Photo: EV-olutionary Process 6

In keeping with its supercar status, the GXE’s cabin is generously appointed with leather and suede.

That’s in part to compensate for the prodigious, hair-trigger torque response of the GXE. In addition, Genovation tweaked the traction-control software so it reportedly responds 100 times faster than stock.

The rolling stock consists of Carbon Revolution carbon wheels, which reduce unsprung weight by 10 pounds each corner. These light-but-strong rims are encased in plump Michelin Sport Cup 2 tires—295/30ZR19 and 345/ZR19 front and rear, respectively, versus the 245/35R19 and 285/30R20 rubber used on the C7 Z51 Performance Package. The brakes are bigger, too—Brembo carbon-ceramic units measuring 15.5 and 15.3 inches. There’s even some regenerative braking on this automatic-transmission version, and Saul says even more is provided on the manual.

Besides all the changes in the powertrain and chassis, the GXE has some additional modifications. The frontal area features some LED “fangs” that echo some elements of earlier Corvettes, while also providing an external battery display (pulsing red indicates a low charge, blue equates to 33 percent, and green means a full charge). Nestled between them is a textured, more porous grille insert for higher airflow. This 3D-printed component was designed by Prefix Corporation, which also provided the carbon-fiber splitter jutting forward from the chin, along with the more-aggressive side mirrors.

The latter alteration prompted a question about the aerodynamics of this particular feature. As we learned from research done for a previous article on the C7’s development, GM engineers went to great lengths using CFD (Computational Flow Dynamics) analysis to ensure the original configuration facilitated airflow to the ducts in the rear quarters, since they are instrumental in cooling the brakes, differential, and transaxle. We asked Erik Stafl of Stafl Systems, LLC—upon whom Genovation relied on for technical assistance in developing the GXE—about this aspect. He assured us that further CFD analysis was done on the new side mirrors, as well as the grille, to make sure the air molecules still followed the correct path.

Photo: EV-olutionary Process 7

A carbon-fiber rear diffuser, also from Prefix, manages the airflow exiting from underneath the rear. Lastly, the taillights were swapped out with some glowing “afterburner” LED units for a more futuristic look.

All told, the imposing persona of the GXE passes what we refer to as the “reunion test” with flying colors. That is, you wouldn’t be chagrined to be seen in this car by your old school chums—something that can’t be said about some of the weird-Harold EV designs we’ve encountered over the years.

Inside the GXE, rather than looking like a mad scientist’s lab experiment with dangling wires and exposed circuit boards, the cockpit is slathered in Alcantara, leather, and soft, nut-brown suede (custom colors are also offered). Hearkening back to the Mercedes 300SL, a bespoke luggage set—in this case made by Lotuff Leather—is also included. And given the vault-like silence of the GXE at speed, audiophiles may have extra appreciation for the acoustics of the custom, 10-speaker Harman/Kardon sound system.

An iPad-sized monitor dominates the center of the console, providing all sorts of electrical data and touchscreen controls for seven different driving modes. Currently the gauge screen forward of the steering wheel is the factory item, but a custom unit is in the works.

Returning to our initial commentary about some possible reluctance to embracing a high-voltage Corvette, V-8 mavens who still chafe at the thought of an electrified Stingray should know that GM already has an E-Ray hybrid in the works as an indirect replacement for the C8 Grand Sport. And for those resourceful enthusiasts who might be inclined to build their own Corvette EVs, GM is already offering an eCrate motor to private customers, along with providing training on installation and service of these systems to dealers and aftermarket companies and shops.

Now for the bottom line. We’ve covered countless customized Corvettes over the years, but the GXE qualifies as

the ultimate upfit, both in performance and style. And the cost reflects that, at $750K a pop. At this price point, and a planned production run of only 75 cars, Genovation is certainly not looking to compete with Tesla or other performance/luxury EVs. But as Pobst observes, “The GXE a pioneering car, a piece of the future. We’re discovering that electricity works really well in high performance, out on the edge.”

No surprise, then, that Genovation plans to offer its well-engineered EV technology to other carmakers. All told, this highly exclusive Corvette offering is an electrifying choice in every sense of the expression.

Also from Issue 143

  • Gus Grissom's ’65 L76
  • Duntov Award-Winning ’54
  • Market Report: C7
  • Early-Production ’84
  • Profile: Tony DeLorenzo
  • ZL1-Powered ’67 Coupe
  • C1-Based Custom Racer
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