Given any real financial freedom, most of us would take a petrol engine over a diesel. Modern turbocharged gasoline engines are better in every conceivable way other than fuel economy and carbon dioxide emissions.
They have oodles of low-down torque that used to be a key turbodiesel USP, as well as being smoother, faster-responding, more flexible, quieter and faster to warm up on an icy winter day. They even have a higher rev ceiling, sound better under load and deliver more driving excitement, more of the time. So why in the name of a tank full of liquidised plankton has Audi decided to switch not just the 2020 S5 to diesel, but the next S6 and S7 as well?
It won’t have escaped your notice that this deeply ironic manoeuvre comes from one of the companies found guilty of manipulating diesel engine emissions as part of the dieselgate scandal; a scandal that permanently changed the automotive landscape and accelerated the development of hybrid and electric cars for Europe and beyond.
I can’t say whether the average car buyer still gives dieselgate a thought when looking at their next new ride, but with Audi itself having acknowledged its wrongs and now working hard on alternatively-fuelled cars even as you read this, it seems a bizarre choice to ‘hobble’ three of its most popular performance saloons/coupes/estates with a dying engine technology. However, it’s not that simple.
Audi hasn’t done this just because it has a surfeit of 3.0-litre TDI diesels lying around (although it probably has). The S models are popular in Europe but they’re not exactly helpful when it comes to lowering Audi’s fleet average emissions; the average CO2 outlay of every car it sells in a defined 12-month period. Like all car makers who sell in Europe, it’s tasked with reaching 95g/km by 2021 at the latest. The 170g/km S5, 214g/km S6 and 225g/km S7, as petrol-burners, are a burden Audi could do without. The S4 will likely join the diesel range soon. Perhaps the next S8, too.
So rather than canning three of its best all-round performance models, the decision has been taken to bump them to the only readily-available solution - diesel power - which will instantly lower all of their CO2 emissions by many tens of grams. We don’t have the final figures for the new cars yet but the difference, with half an eye on the EU’s massive financial penalties for failing to meet the emissions targets, will be huge.
Fortunately there’s a better reason to retain hope for the newly diesel-driven Ss. I can remember the first A5 I ever drove; a high-spec 3.0 TDI that I flung along one of my favourite Lake District test roads. I was staggered at how usable its performance was. That upper middle-management coupe with a slightly lardy body and a heavy engine had no right to cover ground the way it did, wrenching at corner exits and slinging you improbably quickly, via tall, drama-sponge gearing, to the next braking zone. Speaking of which, its stoppers were mighty.
I don’t remember covering that stretch of road any quicker in anything else until I bought a Renault Sport Clio 182. Audi-typical epic levels of grip and a vast well of torque won my respect and admiration. The new S cars will take that to another level with extra tech, better suspension and all the benefits that 10 years of tinkering have brought. The V6 diesels actually sound decent, too, especially with the latest clever solutions.
There’s still a big question mark over whether a diesel S5/S6/S7 can emulate the more entertaining side of the old versions’ games, but there’s another over whether many owners really drive them like that anyway. These aren’t RS models, after all: they’re more like the range-topping A-badged cars but with more poke and trinkets. Perhaps the diesels will actually suit S buyers better… at least until Audi finishes developing something better.