There is relatively little in automotive technology that is truly new. In the
late 19th century, as the motor car struggled for credibility, Dr Frederick
Lanchester developed a device called a harmonic balancer – or balancer shaft
– to reduce vibration and allow an engine to run more smoothly.
It was to be something for which many a petrol and diesel engine manufacturer
has long been thankful. But now Subaru has come up with a “world first”
passenger car “boxer” diesel that is inherently well balanced, minimising
the nuisance of secondary harmonic vibration – with no need of clever Dr L’s
long-used device.
Boxer means that its cylinders are horizontally opposed instead of being in
line (or sometimes in a V), which is the norm. Subaru’s petrol engines are
also boxers – as are those that power the Porsche 911 – but, after almost
nine years’ development, Subaru has fitted a diesel boxer to the latest
all-wheel-drive Legacy Sports Tourer and Outback models.
On sale initially (from £19,995) in its Legacy Sports Tourer and Outback
crossover all-wheel-drive estate, the new 2.0litre, four-cylinder boxer
turbo-diesel will eventually be introduced across the Subaru range.
As well as modest levels of vibration, the engine is quiet when warm, revs
smoothly and delivers its turbocharged 148bhp in a delightfully linear flow.
Maximum torque of 350Nm is available from 1,800rpm but there is no sudden
surge of urge as there is with many turbo-diesels; the boxer just serves it
up almost like a normally aspirated petrol engine. It sounds mildly sporty
when driven hard but purrs on the motorway, although there is typical diesel
clatter at tick-over when the engine is cold.
Allied to a five-speed gearbox (it needs six), the boxer gives the Sports
Tourer a 49.6mpg overall figure with CO2 emissions of 151 g/km, top speed of
126mph and 0-60mph in 8.5sec and the Outback 48.7mpg with 153 g/km, 124mph
and 0-60 in 8.8sec.
Dr L may have been impressed by the truly new application of the boxer layout
that has no use for his famous harmonic balancer but, being an inventor,
would doubtless have said: “Yes, but to make it even better, what
about trying . . .”
Hate to be pedantic but I think you are describing a 'flat four' layout here; a boxer engine has two crankshafts and pairs of opposed pistons sharing cylinders. Light aircraft engine manufacturers are starting to make turbo-charged 2-stroke boxer diesel engines, I wonder if we will see these engines in cars?
Ted, Weston-super-mare, UK