Electric 2025 Porsche 718 to benefit from GT4 ePerformance

Porsche’s EV transition is about to hit a new level of performance – and the new Porsche GT4 ePerformance gives a tantalising taste of what’s to come with future sports cars from the German brand.

In Australia for this month’s Formula 1 Grand Prix, one of two proof-of-concept prototype GT4 ePerformance race cars showcases the next-generation tech of Porsche electric performance, some of which is set to arrive on the all-electric Porsche 718 Boxster and Cayman sports cars (codenamed 983) and soon-to-be-signed-off Mission X hypercar.

The man in charge of the GT4 ePerformance project, Björn Förster, says the technology on the race car gives a glimpse of what to expect in future electric Porsche sports cars.

Key among those is an innovative oil cooling system. Instead of running water or coolant through tubes around the battery pack, the GT4 flows engine oil around the individual cells.

It’s a radical approach aimed at precise temperature control – all in the pursuit of performance.

Förster says oil is not as effective as removing heat as water but that its proximity to the cells – without risk of short-circuiting (whereas water conducts electricity, oil is an insulator) – allows finer control of temperatures, to the point where the 80kWh battery pack is maintained at a constant 45 degrees Celsius.

It’s all about ensuring the GT4 e-Performance can punch out race-winning lap times repeatedly and charge from five to 80 per cent in 15 minutes rather than having to compromise due to excess heat in the electrical systems.

“We solved this problem which is called thermal derating by putting an oil cooling system in this car,” he said. “We’re streaming the cooling liquid directly around the cells. We can get the heat out of the electric motor … and through the inverter and through the gearbox.”

Förster says it’s only a matter of time until such oil-cooled battery systems make it into a Porsche road car – even if that is still years away.

“We will see oil-cooled systems in production cars – I’m not allowed to tell you which ones,” he said, clarifying that it would not be the upcoming 718 (983) or production version of the Mission R, but something further into the future.

“This car [GT4 ePerformance] is about five years ahead of the road car,” he added, referring to the advanced development of the prototype.

The GT4 ePerformance utilises a 900V charging system, something not seen on road-going production cars to date.

The Porsche Taycan and the closely related Audi e-tron GT each uses an 800V charging architecture, as does the upcoming all-electric Porsche Macan. Various EVs from Hyundai, Kia and Genesis also utilise 800V charging.

But 900V is new to the game, something that prompts the question of where such an EV would charge.

It turns out the 800V chargers can already supply 900V. In fact, they can supply up to 920V.

“An 800V charging standard allows them to charge at 920V – this car has 916V,” said Förster, highlighting that Porsche is pushing the limits with the GT4 ePerformance.

He adds that it will “fit beneath the voltage of the charging standard”.

So, why bother with higher-charging voltages?

The amount of power a charger produces is equal to its voltage multiplied the amount of current it supplies.

By increasing the voltage you can either increase the power or reduce the current, the latter crucial to reducing heat during charging.

The GT4 e-Performance also uses an all-wheel drive system, something most race cars don’t bother with due to the added weight of additional drive shafts and differentials.

Expect to see more of it in Porsche sports cars.

That’s because another diff and electric motor is relatively light and brings big benefits elsewhere, specifically with regenerative braking.

When braking hard, the additional weight over the front wheels makes it easier to capture energy on the front axle.

But, obviously, when accelerating it’s beneficial to have more drive directed to the rear.

Förster describes the easy application of AWD as “a completely new playground” for Porsche sports cars – and GT race cars specifically – and one that can benefit not only lap times but also how many laps you can complete between charges.

In explaining that all-wheel drive allows the car to recuperate energy on both axles, Förster says there are huge benefits to energy regeneration, in turn allowing the GT4 ePerformance to complete half an hour at race pace – rather than shorter stints.

The addition of the front motor extends the drive time by about 30 per cent.

“With each minute we are racing we can recuperate up to 1kWh per axle,” he said.

Over a half-hour race that would be up to 60kWh of electricity captured for use within the drive system when accelerating.

Förster also says the company “can play around with the drive balance front or rear”, potentially allowing varying handling dynamics depending on the track or conditions.

It doesn’t quite have the ring of a mid-engined sports car, but future all-electric Porsche sports cars – starting with the 718 Boxster and Cayman – will use a mid-mounted battery system.

It’s all about mimicking the rear-biased weight balance of a 911.

“The perfect Porsche has 58 [per cent of its weight] in the rear,” said Förster, adding that was the target with future EV sports cars.

It means repositioning the batteries from where they are in the GT4 ePerformance prototype, something that comes down to learnings during testing and development.

Whereas the GT4 prototype splits its 80kWh battery across three locations – under the bonnet, in the passenger footwell and in what was the engine compartment – the road versions will place it all in the old engine bay behind the two occupants.

It’s all about allowing for a low cabin and increasing the weight at the rear of the vehicle, something Förster says will improve agility and cornering dynamics.

“It makes the balance way better and also the inertia … the agility will be better.”

The highly-strung, high-revving engine of the 911 GT3 Cup car requires regular maintenance, including an engine recondition after 75 race hours.

The cost is about (gulp…) between 70,000 and 100,000 Euros, or somewhere around $A140,000.
While Förster acknowledges that the battery will likely eventually require a replacement, it should go many years without having to be touched – and the electric motors will also not require servicing.

When they do require a replacement, he suggests 15,000-20,000 Euros should cover it off, making for a far more attractive race car.

“Running costs will be way lower on this car,” he said.

Porsche sells plenty of race cars to private racers as part of its Cup race series around the world.

The plan is for a future production iteration of the GT4 ePerformance to join that program.

The target is to have the EV broadly match the GT3 Cup cars in lap times; the electric version will have way more power, but the additional weight cannibalises some of that advantage and calls for a different driving style.

Still, customer versions of an electric race car are still many years away, likely towards the end of the decade.

The first step is for Porsche to begin selling the next-generation all-electric 718, something expected in 2025.

“To offer a really good price … about 300,000 Euros for a race car we need a proper street car which is already electric … to build an electric race car out of that,” said Förster.

“That’s the main point: we are waiting for to start the development of the next version of this car.”

As with all Porsche new-model releases, expect the volume-selling versions of the 718 to arrive first.

During the car’s lifetime there will be sportier iterations, including track-focused GT models, possibly a GT4.

They’re the ones that will form the basis for the customer version of the GT4 ePerformance.
“GT would be better … it would be the better choice,” he said.

“We will come at the same time [with the race car],” he added, suggesting this would be towards the end of the decade.

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