Audi’s move to turn most of its S cars into diesels seems to have been met with a mix of intrigue and horror. Sure, it’s slightly discomforting to see a car that was once powered by a naturally-aspirated V10 (the S6) propelled instead by a V6 oil-burner, but one step down from the mighty RS models, perhaps a pokey derv motor makes more sense.
In any case, we have been here before, but not with Audi S, but rather Mercedes-AMG. Yep, Affalterbach did once dabble with diesel. Or depending on how you look at it, twice.
Back in the 1980s AMG sexed-up the Spanish-built MB100 van with a body kit and a few other bits, but its first proper, series-production diesel car as an official arm of Mercedes arrived in 2002.
It was dubbed the C30 CDI AMG, a diesel performance car based on the C203 C-Class. For its powerplant, Affalterbach took the C270 CDI’s OM612 inline-five engine - a motor also used for the Sprinter van - and chucked quite a bit of it in the bin before rebuilding it into something much more potent.
Displacement grew from 2.7 to 3.0 litres thanks to an increase in stroke, the turbocharger was swapped for a larger unit, and a more efficient air to water intercooler was fitted. The power jumped from 168 to 228bhp, but the torque gains were even more impressive - while the standard engine made do with 270lb ft, the AMG version had 398lb ft of twist to play with. The overhauled five-pot diesel sent its power rearwards via a conventional five-speed automatic gearbox.
Those figures may not look too hot compared to new 342bhp, 516lb ft V6 TDI, but back then, the CDI AMG’s five-pot had an impressive output for something not fuelled by unleaded. It made for a 0-62mph time of 6.8 seconds which, again, was good going 17 years ago.
The conversion went further than just the engine, too, with the C30 CDI receiving chassis upgrades lifted from the supercharged V6 petrol-powered C32 AMG. It was given a matching visual treatment on the outside too, gaining the same subtle bodykit and 17-inch alloy wheels. Further mirroring its sibling, you could spec the C30 CDI AMG as a saloon, estate or a hatchback ‘Sportcoupe’.
The trouble was the price. Mercedes expected buyers to stump up €49,590 for the car, which was getting on for M3 money at the time. A year after production kicked off, Audi introduced the similarly priced V8 B6 S4, and even Merc’s own C32 was only about €6000 more. Buyers in the UK weren’t even given a chance to decide if the C30 was worth the outlay - it was never built in right-hand drive. It didn’t make it to the US, either.
Inevitably, sales were poor, and while the C32 evolved into the 5.4-litre V8-powered C55 in 2004, the plug was pulled on the C30 CDI AMG the same year, with no replacement offered.
Mercedes-AMG hasn’t built a diesel car since, and although hybrid AMGs are already here and full EVs from Affalterbach will arrive eventually, it’s highly likely the C30 CDI will remain the organisation’s only official derv production effort.