The Lexus GS450h is back for a second time to do its own thing in the large luxury car segment.
Despite diesel engine power accounting for at least half of sales of rival cars – the Audi A6, BMW 5-Series and Mercedes-Benz E-Class – the Japanese contender is sticking resolutely with the petrol-electric hybrid route for its efficiency leader.
While this is only the second iteration of the Lexus GS450h, it forms part of the fourth-generation Lexus GS range released earlier this year.

The Lexus GS250 and GS350 also use a V6 petrol engine, but the GS450h again adds an electric motor.

The combination again brings a combined power output of 254kW, though the redesigned V6 adopts direct fuel injection and switches from an ‘Otto cycle’ combustion process to the more economical Atkinson Cycle found in the Prius and Lexus CT200h.

A higher compression ratio – up from 11.8:1 to 13.0:1 – also brings a broader spread of torque through the rev range, says Lexus, though more importantly in the environmental stakes the Lexus GS450h hangs its hat on, fuel efficiency is improved by 20 per cent to 6.3 litres of petrol per 100km while emissions drop to 147 grams of CO2 per kilometre.
That makes the GS450h 35 per cent more fuel efficient that the Lexus GS250 and GS350 models, and Lexus says the figures will propel its GS hybrid into the top 40 of the federal government’s Green Vehicle Guide that rates vehicles for their cleanliness.

There isn’t even a single diesel-powered model in the GVG Top 100, though for buyers with a keener eye on economy compression engine versions of the rival Audi A6, BMW 5-Series and Mercedes-Benz E-Class compare more favourably.

The Audi A6 3.0 TDI has official average fuel consumption of just 5.0L/100km, followed by the BMW 520d and Mercedes-Benz E220 CDI with a shared 5.2L/100km.

All three Germans are up to $20,000 cheaper than the Lexus GS450h, despite the cost of the Japanese dropping from the previous model’s single-trim $126,000 price tag to a three-tier range spread between $99,900 and $121,900.

More comparably priced versions of the German competitors retain an efficiency advantage, such as the $116,500 Audi A6 3.0 TDI (6.0L/100km), $120,900 BMW 535d (5.6L/100km) and $101,005 Mercedes-Benz E250 CDI BlueEfficiency (5.5L/100km).

Those models are also laden with bountiful amounts of smooth, effortless torque, though Lexus argues the GS450h delivers more power per gram of CO2 emitted.

It also contends the performance of the GS450h is so sufficient that it has ditched the V8-powered GS460.

The 0-100km/h test is despatched in a claimed 5.9 seconds and is certainly not shabby – especially for a vehicle that weighs nearly two tonnes despite a 20kg reduction in mass – though that’s no faster than the old GS hybrid.

Starting the Lexus GS450h is the same as all other Toyota Group hybrids. Press the ‘Engine start’ button to kick the hybrid drivetrain into … silence.

The electric handbrake auto releases as soon as you apply some throttle and you’re away. Though not silently for long. Again as with most other Toyota/Lexus hybrid systems, it’s difficult to prevent the petrol engine from engaging unless below 45km/h and just breathing on the throttle pedal.

The transition from electric only to dual power units continues to be impressively seamless, though, and wonderfully harmonious as the GS450h gathers momentum.

Liberal use of the accelerator pedal builds that momentum with a diesel-like surge, and is of the ‘Overtake on demand’ variety.

Throttle response, however, depends on which driving mode out of Eco/Normal/Sport/Sport Plus is selected.

You could also read those modes, for throttle response, as: Doughy/Okay/Better/Very Good.
The petrol-electric combination is creamy smooth in its delivery, though, even if there can be moments of hesitation – even in Sport Plus mode – that prevent the system from being perfect.
There’s a pleasing growl from the V6 under acceleration, and Lexus has done a fine job of dialling down the typical drone associated with the vehicle’s CVT auto to make the aural experience more befitting of a luxury car. This was particularly important considering the low levels of wind and tyre noise.

The hybrid system in the previous Lexus GS450h was the highlight of the vehicle, because otherwise the predecessor was flawed in a number of ways – especially ride quality, driving enjoyment and boot space that was badly hindered by the positioning of the battery pack.

Lexus is currently going through a transitional phase to make its vehicles better dynamically – as part of Toyota boss Akio Toyoda’s plan to make the automotive giant’s models more exciting.
So the new Lexus GS450h sets out to give owners a feeling of satisfaction beyond the smugness of being seen to be green.
There’s a chassis that’s 14 per cent stiffer, and a new suspension front (double A-arm) and rear (multilink).

And while the dimensions of the Lexus GS450h are largely unchanged, a significant stretching of the axles – 40mm wider up front, 50mm wider at the rear – increases the luxury car’s footprint.

The results are a clear success for Lexus’s engineers because the GS450h builds on the improved driving quality already seen from the other GS models to be vastly better to driver than the old model – whether you favour ride comfort or handling poise, and whether you change the driving mode to Sport that slightly stiffens the suspension.

This applies whether you opt for the $99,900 Lexus GS450h Luxury or top-line $121,900 Luxury Sports, though the $111,900 mid-range F Sport brings sharper steering through a variable ratio rack, dampers with a sportier calibration, as well as a rear-wheel-steer system that at higher speeds can follow the direction of the front wheels up to two degrees to aid handling.

The system – similar to the one introduced by BMW on, first, its 7-Series limo followed by the 5-Series – also helps low-speed manoeuvres by counter steering.

The steering is not especially involving and there’s a vague patch around the straight-ahead position, but otherwise Lexus has found a good set-up.

More work is still needed on the regenerative braking system, though, which continues to serve up brake pedal response that is initially grabby and then overly firm and wooden in feel.

There’s plenty of bite from the brakes, though, with the GS450h F Sport gaining larger brakes up front in deference to its more performance-focused approach.

For owners more concerned about their performance on the golf course, there’s good news at the back of the GS450h. Because where you would struggle to fit a driver (the golfing variety, that is) into the old model’s boot, Lexus claims the new GS450h’s boot will take four sets of clubs.

The battery pack is still the cheaper, heavier nickel-metal hydride type rather than the more advanced and more compact lithium-ion arrangement expected for future Lexus and Toyota hybrid systems, but this time it is positioned vertically rather than horizontally behind the rear seats to help create a deeper boot.

With the revised rear suspension and wider rear track also contributing to improved boot width, capacity jumps by 145 litres to 465 litres.

It’s still somewhat of a compromised shape, and still not that deep, and loses 65 litres to the GS250 and GS350.

Lexus has also squeezed out some extra headroom and rear legroom for a cabin that doesn’t otherwise benefit from any major dimension changes for the vehicle.

The GS interior itself is the best from Lexus for one of its passenger cars or SUVs since it first emerged in 1989 as the luxury arm of Toyota.

There’s a much greater perception of quality as a result of far fewer trim elements that look like they’ve been borrowed from the Toyota parts bin – a problem that afflicts models such as the CT200h small car and RX SUV.

And in a segment that loves a boast about features, the Lexus GS450h Luxury Sports certainly has bragging rights with the world’s biggest multimedia screen – at 12.3 inches. It’s optional on the F Sport.

The content on that screen is controlled by Lexus’s second-generation Remote Touch system.

The flat-joystick-style controller (pictured above, to the right of the gear lever) is now even more mouse-like because you click down to confirm an action where before you had to press a button to the side.

It’s a touch too sensitive, however, and the rotary dial approach of the rival Audi MMI, BMW iDrive and Mercedes-Benz Comand systems still seem simpler and more elegant solutions.

As with all Lexus models, the GS450h adopts the packed-to-the-gunwales policy in contrast to the German luxury brands that seem to believe an options list can never be long enough.

You can see a full list of key features for the Lexus GS450h range that goes on sale in June, though it’s worth pointing out the hybrid gains some features over the GS250 and GS350 – including a radar cruise control system that operates at all speeds and can effectively take control of the vehicle in stop-start traffic.

The key technology of the Lexus GS450h remains its hybrid drivetrain, though. And you certainly have to admire the Japanese brand’s persistence with petrol-electric power despite the overwhelming sales evidence pointing to diesel’s vast popularity advantage.

But for buyers looking for the ‘greenest’ vehicle in the large luxury car class (but don’t forget to tick the option box for the steering wheel made from bamboo rather than wood), the Lexus GS450h also offers tremendous refinement, a well executed interior, strong performance, excellent ride comfort and capable handling.