Here’s How Engineers Are Achieving Lightness in the Heavyweight EV Era
As battery packs become the new albatross that performance cars must lug around, engineers are embracing the challenge to slenderize EVs and usher in a new era of performance.
From earliest days, enthusiasts judged the merits of sports cars through a set of near-unbreakable commandments, creating a virtual holy writ of driving: Fiery power, of course, but only in service of a purer virtue: Light weight, and all the blessings that flowed from it in terms of spirit, agility, and sensation.
The days of truly featherweight Lotuses—or even the 2,780-pound, 1993 Mazda RX-7 R1 I recently waved a tearful goodbye to—are mostly gone. But the dawn of electric performance has really upended the old orthodoxy. Some true believers are troubled by the evolution: Electrified models like the Porsche Taycan are lifting horsepower and torque to unimaginable heights, but some plop more than 5,000 pounds on the scales. It’s bulk that might have Colin Chapman spinning in his lightweight casket.
That doesn’t mean automakers are giving up, however, even as battery packs become the new albatross that performance cars must lug around. Designers and engineers at storied brands—Porsche, Ferrari, McLaren, and General Motors—are embracing the challenge to slenderize EVs and usher in a new era of performance that they’ll bring.
Three-Thousand Pounds: A Thing of the Past?
EV performance mavens suggest you can pretty much forget street-going models coming in around 3,000 pounds. (An Ariel Atom-style EV might be an impractical, track-day outlier). Hell, even today’s ICE-powered sports cars can barely manage it: the 911 Turbo S I recently drove weighs more than 3,500 pounds, and that was with a Lightweight Package. A GT3, Porsche’s welterweight star, weighs 3,222 pounds.
For now, PHEVs from price-no-object automakers come closest. These models can make do with smaller batteries and motors to supplement gasoline engines as they wage an epic last stand.
A pair of PHEVs I recently drove on road and tracks in Spain—the bleeding-edge Ferrari 296 GTB and McLaren Artura—went on electrified diets that would impress a gym rat. McLaren engineers managed to entirely offset the Artura’s 287 pounds of hybrid hardware, including a 194-pound battery. That includes a new carbon-fiber monocoque that weighs just 180 pounds. The Artura’s 3,303-pound curb weight is only a skosh more than a conventional 570S that the Artura easily brushes aside. This 205-mph supercar also emits 104 grams of CO2 per kilometer on the WLPT cycle, not far from a European Ford Fiesta’s industry-leading 99 grams from nearly a decade ago.
During the car’s media preview event, I spoke with Darren Goddard, executive director for production development, who said, “Being weight-neutral at the car level is very important to us. We only add electric weight if we can offset it and the driving experience isn’t compromised.” This, by all accounts, is something McLaren certainly pulled off, and for $237,500, you can experience it, too.
At 3,527 pounds, the mind-melting 296 GTB weighs a little more than an F8 Tributo. The extra plug-in pounds are worth it, though: Ferrari’s V6 sports car can beat any production V8 Ferrari around the Fiorano circuit, including the LaFerrari hybrid.
Still, these British and Italian supercars are merely plug-in hybrids. Their scale measurements benefit from a PHEV’s smaller motors and batteries, versus full EVs that must cram weighty cells into every nook and cranny.
Old Dogs Learn New Tricks
Presently, GM finds itself at an interesting crossroads. It currently builds and sells some of the most rewarding-to-drive examples of ICE-powered sedans ever made—the Cadillac Blackwings—but it’s also poised at the edge of its own electric revolution.
At some level, “mass is mass,” said Tim Grewe, GM’s general director of electrification strategy. “You still have to address the elephant in the car, the battery. But you can negate some of that elephant with the fundamental benefits of electric drive.”
For GM designers, engineers and execs who’ve dedicated lives and careers to improving ICE cars, the pivot to EVs is like working a new muscle. Or, rather, growing an entirely new muscle and then learning to work that. Tony Roma, Cadillac chief engineer and father of the Cadillac CT4-V and CT5-V Blackwings, recalls being tapped to engineer models like the Celestiq—the brand’s first electric sedan which is en route for ogling on the Pebble Beach lawn in August.
“I thought, ‘Have you seen my resume?’” Roma said. “I’m a card-carrying member of the small-block team.” Last summer, after a memorable day lapping the Blackwings at Virginia International Raceway, Roma told me this: “It’s going to be a long time before you can do what we did at VIR with a battery-electric vehicle. Gasoline is a fantastic storage device for energy. That’s not a political statement, just physics.”
Still, though, he also knows that gasoline is archaic and on its way out. “The tech is changing so fast that 10 years from now we’ll have a completely different discussion,” he said.
Roma’s estimate might be a tad off, however. Recently, EVs from the Lucid Air to Porsche’s 718 Cayman GT4 ePerformance underlined game-changing potential at the Goodwood Festival of Speed. The wide-body GT4 ePerformance can already match the Monaco lap times of a 992-gen 911 GT3 Cup racer.
Bjorn Foerster, the GT4 ePerformance head of technical development, said the company’s mindset hasn’t wavered: “We need the knowledge of lightness in cars now more than ever. With this laboratory of ePerformance, we have just started to step into our new playground.”
Porsche set targets four years ago, determined to slim the GT4 ePerformance to a reasonable 3,300 pounds, 300 more than a Cayman GT4 Clubsport or 911 GT2 RS Clubsport. The final weight comes in at around 3,500 pounds, and engineers might have saved 160 more with a carbon-fiber structure. But the company was keenly conscious of what customers—even Porsche racing customers—would be willing to pay.
“Nothing is more expensive than lightweight,” said Holger Eckhardt, Porsche customer motorsports spokesman. “We could develop a 3,000-pound Taycan, but you’d have to spend $1 million. This is not the right way; as a manufacturer, we have to find the right compromise.”
With EVs, Porsche’s performance dogs keep learning new tricks. Try this one, Mr. Chapman: Adding AWD actually makes an EV “lighter.”
“Why would you put on another powertrain to make a car lighter?” Foerster asked. “But that was the big learning we had in the beginning of development.”
To be clear, this fuzzy-sounding math only applies to track driving: all brutal swings from 100-percent throttle to 100-percent braking. But through front-loaded braking dynamics, Porsche learned a driven front axle more than doubles the energy captured via regenerative braking. How much energy are we talking? Enough to carry 550 fewer pounds of battery, according to Foerster and Eckhardt. Hence, a “lighter” electric GT4, LeMans racer, you name it, is theoretically possible.
“For each race minute, we will get one kWh back from each axle,” Foerster said.
In a perfect world, that’s 50 kWh of energy captured over a 25-minute battle, nearly matching the entire 60 kWh of usable power in an 80-kWh pack. Add the two numbers, and the GT4 ePerformance has the 110 kWh required to run a Cup race and—if company history is a guide—take the checkered flag.
Electricity Is a Control Freak
Another compromise to EV flab are near-infinite control strategies that ICE cars can’t dream of.
We’re familiar with EVs that can manage only a few launches or laps before computers limit power to spare vulnerable components. The GT4 ePerformance becomes the first electric Porsche that “can switch without compromise between driving time and maximum power,” Foerster said. No component will reach a thermal condition that requires intervention. That allows running a full Cup race at the ideal spot of 603 hp. Or, toggle programming to run at 1,073 hp for roughly 18 minutes. A 402-hp output extends track time to more than 45 minutes. Such strategies can let makers optimize cars for varying racing or street applications.
Interestingly, Foerster said the most-familiar EV handling advantage—a lower center of gravity—doesn’t much apply to sports cars, whose already-low driving position precludes a typical underfloor, skateboard layout. Otherwise, “the car would be four inches higher,” Foerster said drily. (Cayman Crossover, anyone?) Porsche stuffed a Cayman chassis with batteries from the bottom-up, but that still didn’t add up to an 80-kWh pack. Integrating extra cells atop the front axle, where the fuel tank usually goes, did the trick. The Cayman’s current center of gravity at least held steady.
But if center of gravity is a toss-up, performance controls are anything but. Due to their physical natures in magnetism and torque, electric motors are opening new doors of perception and handling. For the first time in its history, Porsche can minutely monitor a driver’s acceleration and control inputs, and adjust handling behavior—from corner entry to exit—in ways that Foerster said makes today’s torque vectoring seem primitive. The GT4 ePerformance has 10 handling settings to take advantage of this newfound sensitivity.
GM’s Grewe concurs. On EVs like the Cadillac Lyriq, GM is already recalculating electric torque every 10 microseconds via the rotors’ magnetic fields that essentially connect directly to wheels via a gear ratio. That’s impossible with an ICE powerplant.
“So even before a tire starts to slip, you read that in-rotor current,” Grewe said. “You have visibility into a whole new control when it comes to the tire circle. There’s so much more information in EV torque that you can correlate to the tire. Between that and regen, it’s what everyone is working on to beat the truly lightweight cars.”
The Battery Mass and Efficiency Puzzle
Regarding batteries, few experts expect near-term chemistry breakthroughs that will dramatically reduce mass. That makes battery and motor efficiency a prime challenge. Still, that isn’t stopping automakers from trying. Lucid is gaining a reputation for the ingenious miniaturization and punch of its motors. GM and other automakers have dramatically boosted the per-pound efficiency of batteries and motors.
“We’re taking the two heaviest parts, the battery and motors, throwing tech at them, to make them as small as we can,” Grewe said.
Grewe acknowledged that some engineers who’ve spent careers obsessing over every gram aren’t thrilled to saddle cars with hundreds of additional kilos. Yet the advantages of electric propulsion keep them on board.
“With all that, they don’t kick us out of the room,” Grewe said. “They see the progress, they’re not always happy with it, and they want us to do more. But I can convince them I can bring force with mass.”
That force is as inexorable as the climate change sweeping the globe. ICE engines turn (at most) 40 percent of burnt-fossil energy into forward motion. Automakers are pushing EVs to above 90 percent efficiency. They can also recapture at least 85 percent of braking energy, “so an EV only has 8 to 10 percent total energy loss,” Grewe said. “That’s a game-changer versus mass.”
One thing seems certain. Traditionalists who insist on increasingly mythical advantages for ICE are tilting at windmills. If mass is mass, then efficiency is efficiency: The amount of electric energy in the Porsche GT4 ePerformance is comparable to nine liters (2.4 gallons) of fuel, according to Porsche’s Foerster and Eckhardt. Already, experts say, the only reason ICE can even compete against EVs is because of the energy density of its dirtier fuel.
“We have an electric race car with a ‘tank’ of nine liters, running a half-hour on track,” Foerster said. “Our regular race car could run for three minutes” before running dry on the same amount of fuel. In other words, efficiency rises by a factor of 10, and consumption drops with it. If a race series limited ICE and electric racers to the same amount of fuel energy, the ICE car would lose every race in the pits.
“The efficiency of an electric drivetrain is already so good that you don’t have to develop anything more,” Foerster said. “If you’re attracted by lap time, you have to go for an electric car. Works drivers don’t care where the punch is coming from; they just want immediate power and adjustable control.”
Such pro drivers do see room for improvement, especially on track. That includes better, more-consistent feel from regenerative brakes. For any driver, subjective sensation versus objective speed has been a worrisome issue. Porsche is determined to deliver EVs that don’t lose the agility and personality that are the brand’s lifeblood. It sees the 918 Spyder hybrid as a benchmark, along with the Taycan: Proof that an electrified car can be worthy of enthusiasts’ love, despite some avoirdupois.
Every engineer and executive I spoke with expressed solidarity—and offered sympathy—to ICE enthusiasts. They’re enthusiasts themselves, their own EV optimism tempered by nostalgia.
“There are a lot of emotions on classic cars that I love,” Foerster said. “We still have to do our homework.”
These brands must all walk a daring tightrope between technology’s past, present, and future. For every enthusiast who buys a ticket to the coming show, let’s hope these EVs are more ballerinas than circus bears.
Lawrence Ulrich is an award-winning auto journalist and former chief auto critic for The New York Times and Detroit Free Press.