Lexus GS450h 2006 review

It chews some grass, then heads for some old machinery at the side of the road, which it leans on to rub its rump.

The luxurious Lexus is more interesting than the wombat gives it credit for.

It is a great technical achievement. The Lexus team has managed to combine a powerful V6 engine and an electric motor for masses of power and to limit fuel consumption.

Whether or not it will revolutionise the automotive landscape, as Lexus claims, is another question.

It's impressive, but also flawed.

The GS450h is tested on a 1870km trip to Sydney, on to the Blue Mountains and back.

I even venture 47km from Lithgow to a bush cabin at the ghost town of Newnes, once an oil shale production site.

After driving the new Lexus, you wonder whether petrol-electric hybrids really are the answer or whether it will it be a forgotten technology in a few years.

It is expensive for Lexus (Toyota) to develop and produce — it certainly isn't making money from hybrids.

At $121,990, the GS450h slips into the Lexus GS range between the $112,300 V6 GS300 Sports Luxury and the $137,200 V8 GS430.

It gets a range of top-shelf gizmos including adaptive headlights, radar cruise control, keyless start, rear parking camera and the latest-generation satellite navigation.

But the big difference is the hybrid drivetrain.

The special GS combines a Toyota-based 3.5-litre V6 with an electric motor, using a battery that is topped-up through friction from the brakes and engine.

At low speeds the GS450h can run purely off the electric motor, which is eerily silent.

When you give it a push, the GS fires up its V6 petrol engine as well.

Sometimes the car runs purely on the petrol engine.

The combination of both powerplants adds up to an impressive 254kW.

There is 275Nm available on demand thanks to the electric motor and a total 368Nm from the V6 at 4800 revs.

The car uses a continuously variable transmission that constantly changes the gear ratio and feels like it has just one gear.

Lexus says all this provides guilt-free performance.

The GS450h is fast. Lexus says it can do 0-100km/h in 5.9 seconds, faster than its V8 big brother.

Lexus also claims it produces combined fuel consumption figures of 7.9 litres/100km — that, and the 0-100km time, seems optimistic.

Highways, where petrol and diesel engines shine, aren't friendly to hybrids.

The test car achieved an average fuel consumption figure of 8.3 litres on the trip — about what you would expect from a regular Ford Falcon or Holden Commodore using petrol combustion engines and regular unleaded (the GS demands premium).

A sporty and refined diesel, such as the one found in the BMW 530d or Peugeot 407 Coupe, should do significantly better.

Other testers have returned figures of eight to nine 9 litres/100km driving the GS in the city, which is good but is not going to save the planet.

One of the biggest problems is the size of the battery, which takes up a huge chunk of the boot, which now has room for only one large suitcase. The overflow has to travel on the back seat — making it close to useless for family travel.

The boot space would be even more cramped if Lexus hadn't replaced the full-size spare wheel with a space saver, which is not good on a long trip in the bush.

The extra hybrid components also add weight — about 250kg, turning it into a 1865kg car.

The extra grunt of the powerplants overcomes this in a straight line, but the extra weight takes its toll when cornering.

The steering in the Lexus has a dead feel and the nanny electronic stability control is overly protective — discouraging sporty handling.

Its CVT gearbox is the same. It feels strange to not have any gear changes and decidedly non-sporty. The "manual" shift mode is even less convincing.

Still, you can't overlook the car's stunning torque.

Plant the right foot while passing a truck and it will storm forwards with the go of a supercharged V8. It's a pity it sounds like an over-muffled V6.

The only other niggle is the suspension tuning, which is harsher than it should be.

This Lexus is at home in stop-start city traffic, where it runs quietly and efficiently in comfort, but is not perfect.

The 450h is an interesting technological showpiece that owners will enjoy showing to their friends, but it certainly doesn't revolutionise the automotive landscape.