BMW has made diesel power more widely available throughout the 3 Series range from this month, supplementing the 320d and 330d E90 sedan models that have been on sale for some time.

This move also results in far-cheaper entry-level pricing for the E92 3 Series Coupe and E93 Convertible, to the tune of about $16,000.

All models fall under the company’s EfficientDynamics mantra to include Brake Energy Regeneration (generating electric power from energy otherwise wasted as lost heat via the brake system), electric power steering and common rail diesel engine technology.

The 320d badge now extends from the $58,300 sedan to the $61,500 E91 Touring (wagon), $67,500 Coupe, $80,400 Coupe, while the $87,250 330d sedan now gains $94,050 Coupe and 107,050 Convertible stablemates.

Like the 1 and 5 Series models, the 3 Series’ 320d is a 1995cc 2.0-litre in-line four-cylinder engine delivering 130kW of power at 4000rpm and 350Nm of torque between 1750 and 3000rpm.

The turbocharger uses variable turbine technology for a fatter torque curve throughout the rev range, BMW says.

Driving the rear wheels solely through a six-speed automatic gearbox dubbed Steptronic, the 320d engine offers a combined average fuel consumption figure of 5.5, 5.6 and 5.8 litres per 100 kilometres in the Coupe, Touring and Convertible respectively.

In the same running order the 0-100km/h sprint-times take 8.0, 8.3 and 8.7 seconds, while carbon dioxide emissions range from 145 to 153 grams per kilometre.

All models include leather upholstery, a Sports multi-function steering wheel, Bluetooth connectivity, automatic climate control air-conditioning, parking radar, alloy wheels and Aux-in audio control the Coupe and Convertible add Xenon high intensity discharge headlights, while the latter goes a step further with heated front seats as standard.

Meanwhile, the new 330d Coupe and 330d Convertible models employ an all-aluminium high-output 2993cc 3.0-litre in-line six-cylinder turbo-diesel that will be familiar to X3 and X5 owners.

Output figures are 180kW at 4000rpm and 520Nm from 1750rom to 3000rpm, for a 0-100km/h time of 6.1 seconds in the 330d Coupe and 6.5 seconds in the 330d Convertible. Fuel consumption comes in at 6.2L/100km (Coupe) and 6.4L/100km (Convertible) while the CO2 ratings are 164 and 170g/km respectively.

The 330d Convertible’s poorer showings are mostly due to the 225kg weight disadvantage against the 330d Coupe.

The $67,500 320d Coupe BMW is attempting to court buyers away from the Audi A5 2.0 TFSI ($79,990, 155kW, 350Nm, 0-100km in 6.5s, 7.4L/100km and 173g/km) and the $97,500 Mercedes-Benz E250 CDI (150kW, 500Nm, 7.2s, 6.3L/100km and 166g/km).

The $57,800 A4 Avant 2.0 TDI (105kW, 320Nm, 9.7s, 6.0L/100km and 159g/km) and $62,805 C220 CDI Estate (125kW, 400Nm, 8.8s, 6.8L/100km and 180g/km) seem more evenly matched to the $61,500 320d Executive Touring than the coupes are to each other, while there are no four-pot diesel ragtop rivals for the $80,400 BMW 320d Convertible unless you include the moribund $80,800 Saab 9-3 1.9TTiD Aero Convertible (132kW, 370Nm, 9.5s, 6.9L/100km and approximately 184g/km).

BMW points to the $91,900 330d Coupe going up against the A5 3.0 TDI (176kW, 500Nm, 6.1s, 6.9L/100km and 182g/km) while the $104,850 330d Convertible takes it up to the $112,500 A5 Cabriolet (176kW, 500Nm, 6.4s, 6.8L/100km and 179g/km).

The first BMW 3 Series diesel sedan to be sold in Australia was the 320d in mid 2006, powered by a variation of the same 115kW/330Nm longitudinally mounted M47 D20 common-rail direct injection turbo-diesel unit found in today’s 320d.

The 3 Series diesel deluge takes the total of sub 6.8L/100km BMWs on sale to 23 models.

It also tops off a busy year for the company in Australia, during which more than 60 per cent of its model range has come under some sort of change.

Australia is also the only place outside of Europe to have the EfficientDynamics philosophy applied to the BMW range, ahead of the North American and Asian markets.