7 February 2011

Lexus GS450h 2006 car review

Hybrids - 10 years since the Prius first hit the showroom floor; and they still haven't really caught on have they?

Hybrids - 10 years since the Prius first hit the showroom floor; and they still haven't really caught on have they?

It's only been the current escalating fuel prices, not environmental concerns (that have been well known about for years), that have sparked the recent inpouring of queries about hybrid vehicles to the AA Technical Advice helpline.

Truth is, if they didn't save you money, very few kiwis would want one, they're just not that cool...no, in case you're wondering, not even the Honda insight.

Tell you what is cool though; the Lexus GS430. It's as much a luxury sedan as it is a technology showcase, a distinctly different, but equally refined alternative to typical German luxury marques. All with a potent 4.3 litre V8 petrol engine and styling so good you need a bib to look at it. No wonder it was the clear winner in the Luxury category at this year's Automobile Association Motoring Excellence Awards.

What would happen then if you melded the tree-hugging benefits of a hybrid powertrain with the infinitely cool styling, features and more importantly, the power of the GS430? The answer is the GS450h, the world's first hybrid luxury sedan, and in our opinion, it improves greatly on the appeal of the fantastic GS430.

Unlike the GS430, the '450' in the nameplate doesn't refer to the size of the engine. Instead, it's an indication of how powerful the combined energy of the 3.5 litre petrol V6 engine, and the hybrid electric motor arrangement is.

Lexus claim the power output is equivalent to a 4.5 litre V8, but it sips fuel at the rate of a 2.5 litre four, or six cylinder.

At the heart of the GS450's drivetrain is the first Hybrid drive system built for a front-engined, rear drive application. The unit consists of a power splitting device that uses a planetary gear assembly to distribute the engine's energy; allocating a percentage of the 218 kW @ 6400 rpm output to final drive, and some to drive one of the two motor/generators housed in the transmission-sized hybrid unit.

The throttle pedal is merely a request by the driver for power. The splitting device decides how much thrust will be provided by electric motor, and how much from the burning of fossil fuel. This constantly altering ratio removes the need for an engine tachometer, the rev needle instead replaced by a kW gauge that shows power demand relative to throttle input.

Both motor/generator's electrical circuits flow through a Power Control Unit (PCU) that houses an AC-DC voltage inverter, and a (DC) 288v - (DC) 650v converter. The PCU can send electrical current to charge the hybrid's battery pack, or to power the second of the two motor/generators, sending power (via another planetary reduction drive) to the rear wheels.

At the vehicle's launch, Lexus' technical representative spoke at length about exactly how, where and when the engine's energy and electrical current is being distributed throughout the vehicle. As discombobulated looks upon faces of the press conference attendees validated, it's a complex piece of equipment.

For the laymen though, the Lexus incorporates an easy to understand, Prius-style LCD display that shows power flow during the various modes of vehicle operation. After five minutes of driving and observing the screen, it all becomes abundantly clear.

The display doubles as the vehicle's multi-information centre, and occupants can scroll through audio, heater, and fuel consumption data and settings by pressing the touch sensitive screen. It is also gives the driver an extra set of eyes, automatically showing a view behind the car when put in reverse, thanks to a camera in the boot lid.

On the road the drivetrain is magnificent. Die hards will always argue that the visceral roar, and consequent fast-forwarding of surroundings a powerful V8 permits is irreplaceable, and to a degree they're right. But accelerating from 0-100 in under six seconds the GS450h is certainly no slouch and as compensation for the omitted V8 snarl, you'll save $17,000 off the price of a GS430 V8.

In our opinion the GS450h is more proficient handler than its V8 equivalent too, the sports suspension doesn't seem quite as hard over bumps as the 430, and the hybrid feels more balanced. At 1930kg the GS450h is no lightweight, and carries an additional 235kg of mass over the GS430, a side effect of the hefty hybrid drivetrain and battery pack.

Heavier yes, but unlike the slightly nose heavy GS430, with it's V8 lump up front, the GS450h has a more even spread of it's weighty components. The heavy hybrid battery pack sits over the rear axle, compensating for any weight under the bonnet. The result is a more precise and predictable feel when cornering.

There is a notable compromise in luggage capacity between the two however, and the hybrid gives away 130 litres to the V8's 430-litre boot. This could become a vexation come holiday time with the family, but we feel the hybrid's luggage space is still more than adequate for day to day use.

The pros for opting for a Hybrid over a V8 grunt machine seem to far outweigh the cons. Lexus New Zealand feels there still is a market here for the GS 430 among V8 devotees, but we're not so sure.

With the same drool-worthy exterior styling, lavish interior and creature comforts, preferable on-road behaviour, reduced noise levels, more cutting edge technology, vastly greater fuel efficiency and a huge saving over the GS430, we feel the GS450h has what it takes to make an old favourite redundant.

The GS450h comes in one specification and is priced $130,000. Cost options include a sunroof at an additional $3000, and surely a must have is the Mark Levinson premium sound system and DVD changer. It allows you to watch movies on the vehicle's LCD screen and adds $3300; the money you save in fuel can pay for it.

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