2027 Audi RS5 first drive: A performance PHEV with split personalities - Ars Technica
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SAALFELDEN, Austria—Audi may have built a reputation for technology over the years, either pioneering or early-adopting things like all-wheel drive, direct-injection engines, and so on. But it’s also true that along the way it has earned a bit of a reputation for cars that look good inside and out but maybe aren’t the most exciting things on four wheels. Not so for the models reworked by Audi Sport, the company’s motorsports division, which now also spends its time building the company’s new Formula 1 power units. And like those latest F1 cars, its newest RS5 road car also marries together a turbocharged V6 and an electric motor. How convenient. The underlying chassis of the new RS5 is shared with the A5 that we first drove last summer, but the only common body panels between the lesser A5 and this car is the hood; everything else is RS5-specific. Aggressive wheel arch blisters add more than 3.5 inches (90 mm) of width compared to the A5, and massive air intakes dominate the front fascia. At the rear, a pair of large oval exhaust pipes are set into a diffuser. Oh, and you don’t get those kinds of carbon-fiber accents on a regular A5. Perhaps my favorite styling detail? The rear OLED tail lights have a checkered flag pattern (as do the daylight running lights up front).
Wider and lower than the A5 it’s derived from, the RS5 is a true all-weather five-seat performance car. Tobias Sagmeister/Audi
Wider and lower than the A5 it’s derived from, the RS5 is a true all-weather five-seat performance car. Tobias Sagmeister/Audi I did wonder if the oval exhausts had been borrowed from Bentley. Tobias Sagmeister/Audi
I did wonder if the oval exhausts had been borrowed from Bentley. Tobias Sagmeister/Audi
Wider and lower than the A5 it’s derived from, the RS5 is a true all-weather five-seat performance car. Tobias Sagmeister/Audi
I did wonder if the oval exhausts had been borrowed from Bentley. Tobias Sagmeister/Audi
The car looks good—although not as good as the RS5 Avant station wagon that we aren’t getting—but it’s what’s under the aluminum and carbon-fiber bodywork that’s more interesting. Audi’s lineup has been pretty sparse when it comes to plug-in hybrids, but Audi Sport decided that there were some tantalizing possibilities to unlock were it to leverage a high-voltage electrical system alongside a powerful internal combustion engine.
RS PHEV That internal combustion engine shares the same 2.9 L capacity as the previous RS5 but is all-new. It uses a pair of variable geometry turbochargers in a hot-vee configuration (meaning the turbines are on top of the engine between the cylinder banks), with air-to-water intercoolers and air intakes as short as the Audi Sport engineers could make them. Even though it operates under a modified Miller cycle for better efficiency under partial loads, the new engine still manages to generate 502 hp (375 kW) and 442 lb (600 Nm). For the record, that’s 60 hp (45 kW) more than the old V6 while using about 20 percent less fuel. Of course, if you’re worried about fuel consumption, make sure to plug the RS5 in regularly. There’s a usefully sized 22 kWh (net, 25.9 kWh gross) lithium-ion traction battery under the cargo floor that powers (among other things) the 174 hp (130 kW), 639 lb-ft (470 Nm) electric motor that also sends torque to the wheels via the car’s eight-speed ZF automatic transmission. That’s sufficient for about 50 miles (80 km) of emission-free motoring between charges, more than enough for most people’s daily driving needs. Since it’s a PHEV there’s obviously no DC charging ability, but it accepts AC power at up to 11 kW and takes 2.5 hours to recharge the battery.
If you turn down the RS5’s electronic safety net it becomes a completely different car. Credit: Tobias Sagmeister/Audi If you turn down the RS5’s electronic safety net it becomes a completely different car.
Credit:
Tobias Sagmeister/Audi
It’s when both the V6 and electric motor are working together that you get all of the RS5’s performance—630 hp (470 kW) and 609 lb-ft (825 Nm)—making it more powerful but ever so slightly less torquey than the RS6 Avant that stole my heart a few weeks ago. You’ll want to select one of the RS drive modes to access that full performance; as we’ll see later, this car’s character is very electronic mode-dependent. Interestingly, you hear the hybrid system alongside the V6, with hums and whines from the electronics and electric motor that complement the usual induction, exhaust, and mechanical noises.
What’s the diff?
An actuator, overdrive gears, and a differential combine to intelligently transfer torque between the rear wheels. They do so almost fully variably depending on the driving situation and ensure Agility and Stability. Audi
An actuator, overdrive gears, and a differential combine to intelligently transfer torque between the rear wheels. They do so almost fully variably depending on the driving situation and ensure Agility and Stability. Audi
A look at the assembled differential. Audi
A look at the assembled differential. Audi An illustration showing how torque is controlled across the rear axle. Audi
An illustration showing how torque is controlled across the rear axle. Audi
A look at the assembled differential. Audi
An illustration showing how torque is controlled across the rear axle. Audi
Like all performance Audis, the RS5 uses Quattro all-wheel drive, here with a limited-slip center differential that splits power between 70/30 and 15/85 front to rear. We have enjoyed torque-vectoring rear differentials on previous Audi RS models—the ability to send more power to individual rear wheels as necessary has played a big part in why people like cars like the RS3, TT-RS, R8, and so on. In those cars, the rear differential uses a clutch for each wheel to achieve that, but for the new RS5, Audi Sport decided to develop something new, internally. It’s calling the new setup Dynamic Torque Control, and it does away with hydraulic clutches in favor of an 8 kW, 40 Nm electric motor (also powered by the 400 V traction battery) and some planetary gears. The electric motor lives on one side of the axle and applies torque to a powered sun gear at the other side. This sun gear acts on planetary gears, then a fixed sun gear connected to an open differential. It can add or subtract torque from the ring gear to the half shaft for an up to 1,475 lb-ft (2,000 Nm) split across the axle, or send it back to the open differential for a straight 50:50 split. Because it’s controlled by the electric motor, the diff will react in just 15 milliseconds, making the car