Audi Australia opts against 255kW/700Nm S5 TDI pair
BY JUSTIN HILLIARD | 24th Apr 2019
DIESEL may be on the nose in passenger cars but that has not stopped Audi from rolling out two more oil-burning performance models in the form of the S5 TDI coupe and Sportback sedan, although neither are heading to Australia.
Speaking to GoAuto, Audi Australia corporate communications manager Shaun Cleary said the S5 TDI pair is not in the company’s plans “at this stage”.
Instead, it will continue to offer the S5 TFSI in coupe, Cabriolet and Sportback body styles, all of which are motivated by a 3.0-litre turbo-petrol V6 engine that produces 260kW of power from 5400 to 6400rpm and 500Nm of torque from 1370 to 4500rpm.
Conversely, the S5 TDI that is headed to Europe later this year uses a similarly sized unit, albeit with different fuel. It develops 255kW and a massive 700Nm from 2500 to 3100rpm.
This turbo-diesel engine debuted in the reborn SQ5 TDI mid-size SUV that was revealed in February and could be back in Australian showrooms next year. Earlier this month, it was added to the S6 TDI and S7 TDI Sporback large sedans, but neither will be sold Down Under.
Unlike the S5 TFSI, the S5 TDI features mild hybridisation with an electric-powered compressor (EPC) acting as a second, electric turbocharger.
It accelerates the compressor wheel to 65,000rpm in about 300 milliseconds and routinely provides up to 7kW of boost at low engine speeds, helping to eliminate lag from the exhaust turbocharger.
As a result, the S5 TDI coupe sprints from standstill to 100km/h in 4.8 seconds, while its Sportback sibling is just 0.1s slower. Top speed for either variant is electronically limited to 250km/h. For reference, the S5 TFSI coupe and Sportback both manage 4.7s.
The S5 TDI’s 48V electrical system combines a belt alternator starter (BAS) connected to the crankshaft with a 0.5kWh lithium-ion battery located underneath the boot floor.
Thanks to regenerative braking, up to 8kW and 60Nm can be recovered during acceleration to charge the battery, which is responsible for the vehicle’s ancillaries that are still run by a traditional 12V electrical system.
This also improves the idle-stop system, with the engine switching off from speeds as low as 22km/h, while coasting functionality is available between 55km/h and 160km/h for up to 40 seconds.
While Audi has not released its claims for fuel consumption and carbon dioxide emissions on Europe’s recently introduced WLTP combined cycle test, the brand claims the S5 TDI’s mild hybridisation reduces the former by 0.4 litres per 100 kilometres.
Audi’s rear-biased but variable quattro all-wheel-drive system is standard in S5 TDI alongside an eight-speed torque-convertor automatic transmission, while a rear sports differential is optional.
