Big and bold do battle at Bathurst 12-Hour

Bathurst lap times for the GT3 cars are more than 3secs per lap quicker than a V8 Supercar.

Kiwi drivers will be after glory in the 12 hour race, writes Colin Smith

Once around the clock and perhaps as many as 300 times over the mountain - the Liqui-Moly Bathurst 12-Hour takes place tomorrow with an international driver line-up that began practising at Mount Panorama yesterday.

Five years ago the "round-the-clock" Bathurst enduro was a mainly domestic production car contest fought out by Mitsubishi Lancer Evos, Subaru WRXs and BMW 335is.

In 2011 the race was opened to FIA GT3 cars and that move has provided the momentum for the 12-Hour to join the ranks of the world's top endurance races.

It's a multi-class, 50-plus grid with most of the field of 28 cars in a GT3 battle boasting Audi, AMG Mercedes-Benz, Porsche, Ferrari, McLaren, Lamborghini, Bentley, Aston Martin and Nissan contenders.

FIA GT3 is a global formula based on balance-of-performance principles rather than rigid technical regulations.

Such rules allow a 4-litre rear-engine Porsche 911 GT3R to be performance balanced with big displacement front-engine Mercedes-Benz SLS AMG and Aston Martin Vantage V12 racers and the mid-engine McLaren and Ferrari.

Bentley is chasing Bathurst success with three of the Continental GT3 racers contesting the Bathurst 12-Hour.

GT3 rules even have enough scope for Bentley to carve almost a tonne of luxury out of the Continental GT and create a GT3 weapon.

It's the Bentley that is likely to attract the most attention.

Three are entered - two from the British-based M-Sport squad with a driver squad including former Le Mans 24 Hours winner Guy Smith and GT exponents Steven Kane and Maximillian Buhk.

And Australia's Flying B Motorsport - basically last year's race-winning team with a Ferrari 458 Italia - now field a Bentley to be piloted by former F1 driver and Le Mans 24 Hours winner David Brabham with veteran John Bowe and team owner Peter Edwards.

A notable change to the 2105 race rules restricts teams to three drivers (squads of four were permitted last year).

Lap times for the GT3 cars are more than 3s per lap quicker than a V8 Supercar.

It's a Pro-Am contest with each car including at least one amateur or ungraded driver - in many cases the team owner.

Other expected front runners are the Phoenix Racing squad with its pair of Audi R8 LMS Ultra racers, AF Corse Ferrari, Craft Bamboo Racing with two Aston Martin Vantage V12s and the Nismo squad which returns with a single Nissan GT-R GT3.

The sole Kiwi team in GT3 is Trass Family Motorsport campaigning a new Ferrari 458 Italia for Jono Lester, John McIntyre and Graeme Smyth.

Also in the GT3 line-up are Kiwis Craig Baird (Lamborghini), Matt Halliday (Audi) and Chris Pither (Porsche).

Full-time V8 Supercar drivers are missing this year because of a clash with the official pre-season test for the V8s at Eastern Creek with mandatory attendance for full-season drivers.

That has denied Craig Lowndes - who drove the winning Ferrari last year - and Shane van Gisbergen and Rick Kelly a chance to compete against the internationals.

But there's plenty of V8 Supercar talent chasing GT success, including Steven Richards, Dean Canto, Luke Youlden, David Russell, Steve Owen and Tony D'Alberto.

The 2014 12-Hour saw five cars finish on the lead lap - completing 296 laps - and the margin of victory between the Ferrari of Peter Edwards, Craig Lowndes, John Bowe and Mika Salo and the Audi R8 of Harald Primat, Tomas Jaegar and Maximillian Buhk was 0.41s.

During the race Kiwi ace Shane Van Gisbergen, driving Tony Quinn's McLaren 12C, set a lap record of 2m 03.85s - 3.5s quicker than the V8 Supercar record set by Chaz Mostert during the 2014 Bathurst 1000.

The race starts at 5.50am (local time) and runs till 5.50pm.

Free video streaming, audio and live timing is available at bathurst12hour.com.au