Is 2012 The Year Of The Performance Diesel?

The fast diesel car is something of a faux pas. It's a playground dare - every manufacturer secretly fancies seeing how one would be received, but doesn't want to risk making the leap of faith themselves, in case they get sent to see the headmaster. Or their shareholders. The attempts we've seen up until now have extended to been the utterly crackers, disgusting and fantastical Audi Q7 V12 TDi (the world's first production V12 diesel road car) to the other end of several scales (price, size, taste) with the thoroughly sensible Skoda Fabia vRS. You could add the BMW 535d to that list as well, but that was merely the top branch of the Five diesel tree, rather than a dedicated go-fast model.

Since Audi began dominating Le Mans with oil-burning prototype racecars, (a variation of which ended up in the nose of the bonkers aforementioned Q7) diesels are more credible, even acceptable, as hot rods, but after Audi baulked its R8 V12 TDi concept, it's mainly been its Bavarian counterpart making headlines for fast, frugal motors. It's BMW that's now pushing the issue, and really pouring petrol (?) on the diesel quick car flames, teasing a sea change in M car engines. Forget turbocharging the M5, this is much more radical.

The main rumour doing the rounds currently is that BMW has put its M Division stamp of approval on a twin or even triple-turbo straight six diesel, and plans to slot the resulting monster into its bigger M cars, like the F10 M5 and X5/6 M. Horsepower estimates have varied wildly between 400-500bhp, but the torque figure, the headline act of diesel motoring, could be over 650 lb/ft, a full 150 lb/ft over the meaty V8 twin turbo petrol M5. That should equal monster mass-moving and overtaking ability in the hefty models, while simultaneously bettering their twenty-something mpg results. It's quite a recipe, and given how the motoring press has warmed to forced induction M cars like the 1M and M5 since their controversial unveiling, blown diesel M cars aren't too far a stretch of the imagination.

The more intriguing prospect though, isn't how fast BMW can make the socially acceptable diesel motor, but where the fast diesel goes from here. If diesel can properly conquer the SUV and supersaloon niches, then can it spread further, and would we want it to?

The only hot diesel hatch currently doing the rounds is the VW Golf GTD, a GTi lookalike with 168 bhp/258lb/ft. With a glut of hot hatchbacks hitting showrooms in the new year, it'll be interesting to see if anyone else follows suit. Call it devil's advocate if you must, but I wonder if a 180bhp-ish, (with a good slug of torque) TDI lump in an new Astra VXR or Focus ST bodyshell might be just the job for our wallet-conscious times. There'd still be the surge and urge for B road blasts and motorway overtakes, plus an easy 600 miles out of a tank. The current VW Polo GTI is hardly a common sight - would they sell more if there was a tuned up 1.6 diesel motor plumbed in, using bits available in the VW group parts bin? Sure, diesel engines make for more nose heavy handling, but slight sacrifice of ultimate dynamic prowess in return for 50mpg hot hatchbacks might be a trail worth exploring while this pesky recession lingers on.

Supercars will never go diesel, I'm willing to bet - they sell in such minute numbers to discerning customers, for whom the novelty of an oil-burner would not last sufficiently. However, in a wider motoring world obsessed with economy, the manner in which a torque-rich turbodiesel can pull strongly through a seven or eight-speed gearbox is not to be sniffed at, in any size car. Mainstream audiences attitudes can be changed - the Mk1 Fabia vRS is now something of a cult oddity, and quite cool because of it. Lest we forget it was born in 2003, before the current Czech reinvention really got into its stride. A desirable diesel Skoda? Wonders shall never cease.

Sacrilege perhaps, but there will be diesel M-branded cars soon, and if successful, this may be an internal combustion watershed. The only problem I can see apart from fanboy backlash is American emission legislation, which hates upon the diesel engine in urban areas for its higher outputs of particulates and nitrous oxide, which doesn't fly in the fashionable parts of California. Commit a smoky start-up there, and you'll be hearing from someone's attorney. As a result, the hybrid petrol car rules in Eco-merica, and similar rules are set to jump across The Pond soon, which could kill the parsimonious diesel stone dead with high tariffs on its emissions. That'll explain why brands are already moving to ultra-downsized petrol mills like Fiat's TwinAir powerplant, to avoid the gathering legal storm.

Will anyone dare invest in the diesel, and give it a moment in the glamorous echelons of the performance car, before it heads back to agriculture and haulage? 2012 is the year of reckoning. The next halo company cars really might be coming to the black pump near you, for a short time only.