Silence. Not something you expect when you’ve just fired-up Porsche Motorsport’s hottest new development prototype. But then there’s never been a Porsche Motorsport product quite like the 718 GT4 ePerformance.
This full-EV machine – which packs a 1073bhp punch and can lap most racetracks faster than a 992 Cup car – is billed as the future of Porsche’s one-make motorsport business. This makes the GT4 ePerformance a Big Deal, both for marking the moment Porsche took another emotive step away from internal combustion, and for the company accepting that its motorsport customers (of which there are thousands) will expect and want to go racing in EV machines .
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Crucially, it’s also a pointer to what we can expect from Porsche’s future EV sports cars, as everything learned in the development of this motorsport test mule will inevitably be fed into future Porsche road car programmes. This makes our test of the ePerformance a tantalising first taste of what Porsche’s core sports car range will offer when fully electrified models eventually come to market.
Porsche had two starting points for this project. The first and most obvious is the 718 Cayman GT4 Cup, which Porsche Motorsport build alongside its 911 Cup, GT3 R and RSR racers. This was then adapted to accept an evolved drove EV powertrain taken from the Mission R concept, which we last year (evo 293).
Porsche also plundered its racing parts bin, fitting the GT4 Cup with 911 RSR suspension, then wrapping it in a bespoke wide-track body made by Porsche Style. With huge wings and an even huger rear diffuser it looks every inch the ruthless race car, though lightning bolt test livery aside it offers almost no clues as to what makes it so special.
So much of Porsche’s recent racing activity has informed the development of this car. From the e-motor technology employed in the 919 Hybrid to the hugely sophisticated control systems that are the real hotbed of innovation in Formula E. Look back further and the 918 Spyder and 911 GT3 R Hybrid (which you’ll recall used a flywheel KERS system) have all played their part. It’s reassuring to learn that when you’re at the vanguard, motorsport remains the ultimate proving ground for fast-tracking ideas and getting things to work.
We’re all having to recalibrate what constitutes impressive power outputs in an EV world, but with well over 1000bhp the ePerformance leaves you in no doubt it’s a major-league machine. With two electric motors – one in the nose, approximately where the petrol tank would have sat in the regular GT4, the other where the GT4’s flat-six would have been – it’s something of a stopgap platform in terms of packaging, but the principle of A robust, serviceable and cost-effective EV racing car is clear to see, with the same gearbox, electric motors and pulse-controlled inverters on the front and rear axles offering smart modularity.
EVs always pay a weight penalty versus ICE, but at 1500kg the 1073bhp, all-wheel drive, widebody ePerformance isn’t excessively heavy, especially if you consider the latest rear-drive, narrow-body 500bhp petrol-engined GT4 RS Clubsport weighs 1330kg . Whichever way you slice it, the ePerformance is a whole new level of Porsche GT car.
It’s an intriguing car to be around. Sitting impassively on axle stands with a fat charging lead connected to its rump, its headlights blink slowly as its battery cells chug greedily away on charged particles. Unlike a petrol-powered car, the ePerformance seems to have a life force even at rest.
Before we’re let loose driving solo we’re treated to a passenger ride alongside Timo Bernhard. As one of Porsche’s main development drivers on the ePerformance program he knows the car better than anyone. Unsurprisingly, he’s in the groove from the moment we leave the pitlane, punching the throttle and leaving my stomach behind in a way only an EV can. The precision and immediacy of his inputs are almost binary, but this belies a degree of finesse and sensitivity that’s making fine adjustments throughout the braking, turn-in and corner-exit phases.
Like Timo we will run in two settings – Drive Mode 3, which is effectively Race mode and yields circa 600bhp, followed by a second run in Drive Mode 9, which equates to Qualifying mode and liberates every last kW the ePerformance has to offer. The former is good for 30 to 40 minutes of racing with no tailing-off of power or performance, while the banzai Quali mode can be sustained for 15 minutes. Again, with no performance drop-off, or ‘thermally induced derating’ to give it the correct EV terminology.
It’s in the heat management of the ePerformance electric motors and battery system that Porsche has made big leaps, thanks to a direct oil-cooling system. This circulates special low-viscosity lubricant through the batteries and the motors via a front-mounted oil cooler to maintain these temperature-critical components at optimum temperature. Because the fluid washes over the full surface area of the battery cells it manages the heat effectively and efficiently.
To allow capacity for regenerative braking to be fed into the battery cells at the first braking zone, the ePerformance starts each session with 85 per cent charge. Porsche says that in the course of a typical race as much as 50 per cent of the total energy used would come from regen, which shows how effective the system is, and how much the batteries have to cope with in terms of rapid charging and discharging .
Talking of rapid charging, the GT4 ePerformance – which employs 900V EV architecture with a charging capacity of 350kW – is charged via a monolithic charging station that Porsche has brought to the test and placed immediately behind the pit garage. It takes the car from 5 to 80 per cent charge in circa 15 minutes. Oh for that kind of turnaround time at your local public charging station.
Driving the ePerformance is an unforgettable experience. One which begins with a pre-flight routine that’s laughably simple and eerily quiet. Once switched on, there are a few clicks and whirrs from within the machine. Then all you need do is put your foot on the brake, select your Drive Mode via a rotary control on the steering wheel, squeeze the throttle and away you go. No fuss, no howling petrol engine or fear of being humiliated by a sharp clutch, just a smooth take-off accompanied by a whirr that’s mostly drowned out by the whine and crude clatter of the differentials and other rotating components.
Floor the throttle and the soundtrack switches in an instant, a piercing shriek of the electric motors building endlessly in pitch and volume as speed builds. There are no gears, so you just point and shoot. That limits your sense of interaction with the machine, but it does allow you to focus all your attention on what’s fast-forwarding through the windscreen.
From the inside it’s a maelstrom of those mechanical components combined with the otherworldly sound of electrical energy being under acceleration and harvested under braking. From the outside it sounds like a cross between a gas turbine and a low-flying jet. A gridful of these will make a hell of a racket.
In Drive Mode 3 the performance is stonking up to 120mph or so, but then you feel the ferocity of the initial acceleration begin to soften a little. In Drive Mode 9 it is on another level, that unmistakable sensation of accelerative freefall feeling pretty much unrelenting. On Valencia’s start-finish straight the difference in V-max is significant, 600bhp taking you to 160mph, while unleashing the full 1073bhp slingshots you to 172mph within the same distance.
That Quali mode speed advantage is mirrored at pretty much every point on the lap, the ePerformance arriving at the braking points some 10-15mph faster. It’s a unique challenge that you simply don’t get with conventional ICE-powered race cars, and something that really focuses your mind when trying to slow the car at the end of the main straight.
Braking has always been the greatest challenge in any hybrid or all-electric high-performance car. In a race car it’s even more critical because braking efforts tend to be 100 per cent, with little or no margin for error. The constantly fluctuating levels of regen and the need to manage this effect can play havoc with pedal feel, which in turn meddles with the consistency you need in order to nail your braking points with absolute confidence. The GT4 ePerformance has pretty much eradicated all of those issues, though it still requires skill to find the limit under braking, but only because you’re adapting your technique to find it.
It’s a challenge with reward. Unlike 99 per cent of contemporary racing cars, rather than hammering the brake pedal as hard as you can, then bleeding off the pressure as you close in on the slowest point of the corner, you need to apply significant measured pressure that rapidly builds towards maximum braking, then keep it there with sensitive modulation of pedal pressure.
If you’re not sensitive enough it’s possible to lock, or at least under-rotate, a lightly loaded inside front wheel without being fully aware of it’s happening. But when you consider you’re operating within a ferociously complex brake-by-wire loop, in which braking effort and regen is being continually monitored, balanced and blended between retardation provided by the conventional discs and pads and the resistance from the e-motors when acting as generators, it’s a wonder they ever do the same thing twice. The fact you can derive enough feel and control to use your skill to make this system work better is incredible.
The enormous effort Porsche has put into understanding and exploiting the unique dynamic opportunities a super-smart all-wheel drive EV drivetrain affords has resulted in the GT4 ePerformance displaying some very neat tricks. These are most noticeable – and most exploitable – as you enter the final phase of braking and just begin to point the car into the apex. In short, once you begin to understand how he wants to be driven, the ePerformance comes alive.
Nail your braking and segue smoothly from middle pedal to initial steering input and you feel the car magically rotate. Not with enough yaw to need rapid correction, but just enough to make you think you do. It’s a wonderful sensation, and a behavior that has clearly been dialed-in to counter the natural balance of the GT4 ePerformance, which tends to push towards understeer if you don’t hold your braking deep enough into the corner to initiate the magical rotation.
This engineered agility serves to take some of the burden away from the front tires, and also tightens your cornering radius, so you can get the car stopped, turned and pointed towards the corner exit without having to lean so hard on the front tires. From here it’s a case of swallowing hard and nailing the throttle, trusting that there’s ample grip and traction to fire you out with minimal drama – aside from the rocket-sled punch, which never feels less than dizzying.
I’ve made no bones about being lukewarm towards EVs. Partly due to the everyday limitations resulting from a woeful charging infrastructure, but largely because they don’t possess the dynamic finesse, warmth of character, depth of engagement and nuanced pleasure that pretty much any half-decent petrol-powered hot hatch, sports car or supercar readily delivers.
The GT4 ePerformance is still a sledgehammer in terms of its heavy-hitting accelerative power, but it also demonstrates an ability to deliver the shades of gray upon which driving experiences that live long in the memory depend. That’s immensely reassuring, as it shows those qualities for which Porsche is rightly renowned are being refined, reinvented and reformatted in ways that will enable EV sports cars to deliver deeper and more meaningful driving experiences that genuinely appeal to people like us.
Porsche 718 GT4 ePerformance specs
|Motors||Two, 800kW total|
|Power||1073bhp in qualifying mode|
This story was first featured in evo issue 299.