M276

The M272 it replaced was a 90° V6, an angle that suits a V8 and forces a six to carry a balance shaft simply to stay smooth. For 2011 Mercedes-Benz went to 60°, which a six balances naturally, and deleted the shaft along with its cost and its friction. Nothing else was carried over. Despite being drawn while Chrysler was still inside the group, it shares nothing with the Pentastar beyond the vee angle. The rest was the BlueDIRECT toolkit launched beside the M278 V8: piezo direct injection firing two or three sprays per intake stroke, multi-spark ignition, fast timing adjustment on all four camshafts, and demand-controlled fuel, oil and water pumps.

Stuttgart claimed up to 24 per cent better fuel consumption than the M272 with more power alongside it, which is why the cars wore BlueEFFICIENCY badges. The 3.5-liter naturally aspirated version came first; from 2013 a smaller 3.0-liter twin-turbo arrived for the W205 C 400, then a lower-boost 3.5 twin-turbo that matched its numbers on less fuel, then harder-boosted versions for AMG’s 43-badged cars. Its ending followed the logic that had created it: once a 48-volt system could take the ancillaries off the front of an engine, the packaging case for a V6 collapsed, and the M256 straight-six took over from 2017.