What's all this about?
Audi seems to be slowly turning all of its S-models to diesel. Recent announcements from Ingolstadt have confirmed that both the S6 and S7 will be powered by a 347hp/700Nm 3.0-litre V6 TDI unit, which is also going to appear in the SQ5 performance SUV, where it will most likely replace the underwhelming TFSI that was the original motor for the second-gen SQ5. Well, now the S5 has run aground on the same diesel rocks - returning to the Audi UK showrooms from May after a brief, WLTP-enforced hiatus, the S5 will now be powered by a TDI engine. This is confirmed for the Coupe and Sportback models, with the Cabriolet as yet unspecified.
So it's a straight swap, is it? TDI for TFSI?
Yes, like an early, pre-halftime substitution in a football match for a player who doesn't appear to be injured, you can't help but feel that Audi has done this not just for emissions reasons, but also because the S5 never lit anyone's fire (although we actually preferred the S5 TFSI to the RS 5 flagship). If you're going to have a fast, assured but slightly uninvolving mid-spec performance coupe, why not save a bit of fuel while you go about your business?
Can you give me the specs, then?
Yup. Like all of Audi's latest diesels, the S5 TDI twins are powered by a 48-volt mild hybrid electrical system, which serves an 'EPC' in the powertrain to prevent turbo-lag. As with the SQ5, S6 and S7, the TDI in question delivers 347hp and 700Nm - respectively, 7hp down and a whopping 200Nm up on the old TFSI S5. This means that the TDI versions are almost as fast: the S5 Coupe diesel does 0-62mph in 4.8 seconds while the Sportback takes another tenth to get to the benchmark, which puts both cars 0.1 and 0.2 seconds down (respectively) on their petrol-powered predecessors. The top speed of the S5 TDIs remains artificially pegged at 155mph, but fuel economy is up to 45.6mpg with CO2 emissions as low as 161g/km. That, reckons Audi, means the TDI versions are 19 per cent more efficient than the cars they replace.
And everything else is the same?
So far as we can tell. There are some minor gewgaws, in terms of tickled bumpers and LED lights and optional Sport quattro diffs and so on, but in essence it's the same eight-speed Tiptronic automatic gearbox and quattro all-wheel-drive system as used before.
Matt Robinson - 17 Apr 2019
