Overall rating: 4.5/5
With 180hp and 270Nm the engine we tested was at the upper echelons of what can be achieved with the new three-cylinder unit (BMW reckon 200hp is the peak in standard form with the i8 using a modified version to achieve 220hp). Even still, power aside, the powerplant proved itself to be as smooth as a BMW buyer would expect while offering the responses and sportiness not normally associated with three-cylinder engines. Not quite a full five-star score though as this engine signifies BMW's move towards front-wheel drive, but more importantly it will be two years at least before we get to drive it in the wild.
In the metal 3/5
To look at, the prototype cars that lined up outside the hangar at BMW's recently opened Driving Academy in Maisach are exactly the same as the 1 Series that we currently have in Ireland. That is somewhat the point though as the reason we were invited to the facility was to test the engine rather than the car; the 1 Series is just a convenient platform.
The new three-cylinder unit will find its way into the 1 Series first, to act as the entry-level into the BMW family and while the BMW personnel were 'not allowed' to say if it will feature in the 3 Series line-up too, you can be sure that, if the Bavarians convince customers the concept works, the 3 Series will be offered with the new unit in time.
Driving it 5/5
On paper, a three-cylinder engine in a BMW may not sound all that good an idea. While many car makers, including Volkswagen and latterly Ford have begun to turn to three-pots due to their cost and efficiency benefits it seems somewhat at odds for a premium manufacturer, and specifically BMW - a brand synonymous with dynamics and driver appeal - to even consider one.
That feeling disappears the moment you prod the starter button and the engine barks into life. To compensate for the lower frequencies of the characteristic three-cylinder thrum the exhaust note has been tuned to effectively drown it out with the result being a sporty, purposeful growl. Prod the accelerator and the car takes off with the kind of verve you would not normally associate with a three-cylinder unit - this is more like a TwinPower four-pot than an economical three.
Unlike some three-cylinder engines, which start life as a four-cylinder, the BMW unit shares its genes with the Bavarian's traditional six-cylinder unit. BMW describe it as a six-cylinder chopped in half and while it is a rather simplistic description it does somewhat work. To maintain the smoothness normally associated with BMW engines a balance shaft is used.
This means the new engine is as smooth and responsive as you would expect a BMW's to be. The first few corners of our two-lap test drive were taken tentatively to acclimatise to the track, but once opened up the three-cylinder began to show its true talents. It craves revs, with speed and exhaust noise rising the closer you get to the 6,500rpm redline. At that point the engine note seems more flat-four than three-pot, and as an 'entry level' unit it is thoroughly addictive. Grab the left steering wheel mounted paddle to drop gears in preparation for the rapidly approaching chicane and the exhaust begins to pop and crackle as the engine management unit automatically blips the throttle. Once clear of the chicane the revs again rise to a crescendo before being dulled by the oncoming slalom that the car tackles with abandon. The mounting of the engine (far back in the engine bay), and the resultant weight distribution, allows you to attack each cone with confidence.
What you get for your money 4/5
The three-cylinder family is at least two years away from production with the BMW i8 hybrid supercar being the first recipient. With that in mind BMW does not yet know how much cars equipped with the new engine are likely to cost, but they will be positioned as the entry-level models so should be cheaper than existing four-cylinder counterparts.
Whatever the cost turn out to be, for your money you get an engine that is between seven and eight centimetres shorter and ten kilograms lighter than a comparably powered four-pot making for obvious dynamic advantages. While still in development, BMW engineers are aiming for between a five and fifteen per cent improvement in fuel economy and efficiency over four-cylinder units depending on the power output. A sub-99g/km petrol model could also be on the cards if BMW can get the tuning right.
Worth Noting
The three-cylinder unit tested is the starting point for a family of engines that will, in time, replace BMW's latest offerings. From the outset the engine has been designed with modularity in mind meaning it will spawn four- and six-cylinder versions in both petrol and diesel. This will be achieved through commonality across the family with up to sixty per cent of the three-cylinder engine being comparable to the other members of the family. This allows for a streamlined manufacturing process with one production line able to churn out a six-cylinder diesel immediately after a three-cylinder petrol.
The engines have also been designed to be mounted either longitudinal (BMW's standard fitment) or transverse allowing for both rear- and front-wheel drive configurations, paving the way for BMW's first front-wheel drive car - as previewed by the Concept Active Tourer at the Paris Motor Show.
Summary
Purists will undoubtedly be up in arms at the prospects of a front-wheel drive BMW, but as the premium market shifts it is inevitable. BMW simply needs to cut costs to maintain its position at the head of the pack. While we cannot yet comment on the front-wheel drive cars we can confirm that fans of BMW have nothing to fear from the new three-cylinder engines. Through clever engineering BMW has managed to make a small, economical engine that is as smooth, responsive and sporty sounding as its six-cylinder offerings.