Though the Volkswagen Group's two-litre turbo is the leading exemplar, the four-cylinder engine is, at this very moment, coming into vogue.
Four-cyclinders deserve a little more respect
They say the first sign of insanity is repeating the same process over and over again and expecting a different response. Just as ominously, repeating oneself ad nausea is the very first sign of that scariest of afflictions, Alzheimer's. Repetion, therefore, is not something to be repeated.
Nonetheless, I am going to reiterate, for what is surely the umpteenth time, that the turbocharged little 2.0T four cylinder is the best engine that Audi, and indeed the entire Volkswagen Group, makes. Mated to a new eight-speed automatic transmission, as it is in the new Q5 luxury crossover-cum-SUV, it is the very epitome of efficiency; it averages but 9.3L/100km, yet is incredibly sprightly (that would be its 350Nm of torque talking), wonderfully smooth and, with much thanks to that aforementioned eight-speed trannie, a model of vibrationless civility.
But, I come not to praise the Q5 (or even Audi, for that matter) but to bury the V8.
Long regarded - and with much justification - as the poor man's choice to the V6 or even a V8, the four-cylinder has traditionally toiled in the humble recesses of Ford Fiesta and Hyundai Pony engine bays, their buzzy and lethargic performance seemingly deliberately injected to admonish those less, er, fortunate to get off their sorry behinds and get a job that might afford them a "real" car.
No more. Though the Volkswagen Group's two-litre turbo is the leading exemplar, the four-cylinder engine is, at this very moment, coming into vogue. Perhaps the first sign of this ascendance of sensibility was the fourth-generation Camry, of which its 2.2L inline four was the engine of choice in then still unburstable Toyotas, at least if you wanted the most robust, reliable powertrain available. Since then, virtually all family saloons have placed more emphasis on their four-banger powertrains to the detriment of their V6s, with the Camry, Nissan Altima and Honda Accord all boosting the displacement, performance and economy of their inline fours with comparatively modest development to their six-cylinder technology.
But recently came news that the once proletarian four has indeed reached the courts of kings; Mercedes-Benz, at the Paris Auto Show, announced that no less that its range-topping - and segment-leading - S-Class would be powered by a diminutive 2.2L four. Oh sure, it's a diesel that should pump out outsized levels of low-end torque. But, it nonetheless sports but four pistons, a number that would have been heretical had it been announced just 10 years ago.
Mercedes says the little four's 500Nm of torque is the result of dual-stage turbocharing and equal to many current six-cylinder diesels. More importantly, Mercedes says the two-ton S250 CDI averages 5.7L/100km and emits but 149g of CO2 per kilometres driven. This makes the puny-powered S-Class the first car in the ultra-luxury segment to average less than 6L/100 km as well as the only one to attain CO2 emissions below 150g/km, the latter significant since many European countries tax vehicles based on emissions levels and the former of consequence because of stringent US fuel-economy standards due in 2016 and 2025. Nor does the big Merc suffer much in the driving enjoyment department, the big saloon enjoying a 240kph top speed and more-than-adequate eight-second zero-to-100kph acceleration.
Audi, meanwhile, is likely to offer a hybrid version of its A8 colossus powered by - you guessed it - the 2.0T mated to an electric motor. Combined, the two can transmit as much as 241hp and 485Nm of torque though the aforementioned smooth-shifting eight-speed transmission. Audi claims a similar eight-second zero-to-100kph acceleration time and preliminary figures set the fuel economy at 6.2L/100 km.
Even if that doesn't quite match the 5.8L/100 km that the same car powered by Audi's 3.0L V6 TDI boasts (the 2.0T, methinks, is probably sweeter however), it does point to a growing trend for greater deployment of four-cylinder engines. With their comportment ever more pleasurable and the pressures for the greening of the automobile increasing, we should be embracing this downsizing rather than treating the four-pistoned engine like the lowly stable boy come to visit.