JAGUAR says it expects a 30 per cent leap in sales of its entry-level XF sedan with the arrival in Australia of a more affordable 2.0-litre four-cylinder variant that fills a big gap in its armoury against its mainly European opposition.

The $68,900 (plus on-road costs) XF 2.0 Luxury is more than $20,000 cheaper than the previous most affordable petrol Jaguar – the $89,400 V6 Luxury that it supersedes.

At the same time, the four-cylinder Big Cat also undercuts comparable rivals such as the BMW 520i, Audi A6 2.0 TFSI and Mercedes-Benz E200 by about $9000-$11,000.

The 177kW engine is the same turbocharged direct-injected unit employed in Ford Australia’s EcoBoost Falcon, and is also used in various states of tune in the Ford Mondeo, Range Rover Evoque and some Volvo models.

This acclaimed engine was developed when all these brands were part of the same happy Blue Oval family, before Ford decided to divest itself of its premium brands.

Like the near-identical EcoBoost variant in the Falcon, the first petrol four-cylinder engine in Jaguar’s XF puts the power to the tarmac via the rear wheels, but uses a more advanced eight-speed ZF automatic transmission instead of the six-speeder in the home-grown Ford.

This eight-speed box has now been applied across the XF range as part of a 2013 model update that also includes a new 250kW/450Nm 3.0-litre supercharged V6 variant.

The normally aspirated V6 and V8 petrol engines have been deleted, but the two turbo-diesel models – in 2.2-litre four-cylinder and 3.0-litre V6 guises – have been retained, along with the celebrated supercharged 5.0-litre V8 of the XF range flagship (for now), the XFR.

At this week’s 2013 XF launch in Sydney, the focus was on the 2.0-litre i4 petrol engine that will be offered in two XF specifications – $68,900 2.0 Luxury and $75,500 2.0 Premium Luxury.

Jaguar Australia, which introduced the XF in 2008 and gave it a facelift in 2011, says the 2.0-litre petrol engine effectively replaces the 3.0-litre normally aspirated V6, while the supercharged V6 replaces the naturally aspirated V8.

Despite its diminutive dimensions, the four-cylinder engine develops 2kW more power than the outgoing V6 (177kW at 5500rpm versus 175kW at 6800rpm), as well as more torque (340Nm versus 293Nm), helping to slice the 0-100km/h acceleration time from 8.3 to 7.9 seconds.

As well, the smaller engine uses less fuel, down from the V6’s 10.5 litres per 100km to 8.9L/100km – an improvement helped by the eight-speed transmission and lighter mass of the smaller aluminium-block engine.

Jaguar Australia brand manager Mark Eedle said the advent of the new i4 petrol entry models opened a door to a larger potential market for Jaguar and the XF.

He said about 29 per cent of luxury car sales in the XF’s class were powered by four-cylinder petrol engines.

Mr Eedle said that, with the 2.2-litre diesel model already making up about 28 per cent of XF sales, Jaguar expected four-cylinder variants to comprise more than half of all XF sales from now on.

So far this year, Jaguar has sold 557 XFs – up 26.3 per cent – making it the British marque’s biggest seller by far in this market and placing it mid-field in the large luxury car segment, which is running at about the same pace as 2011.

By comparison, Jaguar Australia has sold just 54 of its more expensive XJs and 63 XKs this year.

The company expects to land about 30 to 40 2.0-litre XFs in Australia before the end of the year, along with a shipment of new supercharged V6 models that it intends to publicise in the New Year.

The blown V6 – which is also available in the bigger XJ sedan flagship – pumps out 250kW at 6500rpm and 450Nm between 3550 and 5000rpm, driving the XF from standstill to 100km/h in 5.9 seconds – 0.2 seconds slower than the V8 it replaces.

However, the V6 pays dividends at the fuel pump, returning 9.4L/100km compared with a thirsty 11.1L/100km for the V8.

The supercharged V6 comes in one Luxury specification at $95,650.

Apart from the arrival of the new petrol i4 and supercharged V6, engine changes include tweaks to the 2.2-litre i4 diesel, delivering a power gain of 7kW to 147kW, while fuel consumption has been trimmed to 5.1L/100km and emissions to 135 grams of CO2 per kilometre courtesy of idle-stop, which has been added to all diesel and V6 and V8 petrol engines

The XF range gets some interior tweaks such as new infotainment features, including a 30gb hard drive, a more capable sat-nav system that zooms in when the car approaches an intersection, and a browsing function for iPod tunes. New high-end Meridian sound systems are also available.

Jaguar says suspension tweaks deliver a better ride without upsetting handling.

Standard features on the 2.0 Luxury include Alcantara seats with four-way front-seat electric adjustment, keyless entry and start, automatic transmission with sports shift and steering wheel paddles, leather-bound steering wheel and 18-inch wheels.

The Premium Luxury version adds items such as six-way electric-adjustable seats cloaked in full leather.

While the new sedans are arriving showrooms this month, the new XF Sportbrake wagon model is only available on special order.

Jaguar also confirmed it will take the blistering 404kW, 300km/h supercharged 5.0-litre V8 XFR-R that was unveiled at last week’s Los Angeles motor show, making it the new XF range-topper from mid-2013.

Like the Sportbrake and XKR-S sports flagship, the XFR-S will only be available on pre-order.

Pricing is yet to be announced, but expect a sticker “north of $200,000”.