THERE's no question Falcon's powerful new twin-cam 4.0-litre six is thirstier than before, as you'd expect with a hefty weight increase - in this case the XT weighs a big 144kg over its outgoing equivalent, the Forte.

But there's not much in it: not enough to change the AUIII Falcon's claimed fuel economy figures of 11.5 litres per 100km on the city cycle and 7.6L/100km on the highway, producing an average of 9.55L/100km.

Figures are based on the standard five-speed manual, which has slightly lower overall gearing and so uses a little more fuel on the highway than the optional four-speed semi-auto.

Despite Barra's extra weight, Falcon still produces a better power-to-weight ratio than Commodore and, while its inferior fuel economy can become expensive, on current fuel costs it adds up to less than the difference between the two for an average full comprehensive insurance policy.